At this point, the article analyzes the effect of losing speed in the series of repetitions within strength training.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

SUMMARY

• The loss of speed in the series can serve as a predictor of the degree of metabolic stress caused by training, and therefore it is a good indicator to estimate fatigue.
• Doing half or less of the repetitions achievable in the series produces notable improvements in muscular strength and sports performance.
• People who train for improved health should not do even half of the possible repetitions in the series.
• Most experienced athletes with medium-high strength needs will probably be able to perform at most half or 1-2 repetitions more than half of the possible ones.
• A subject should not lose more than 20-35% (depending on each exercise) of the speed of the first repetition in the series.

This is the second question related to the definition of the stress character (CE) as a solution to the problems raised by RM and XRM. Speed ​​control not only makes it possible to know very precisely the true effort that a given load (mass) represents when doing the first repetition of a series, but also allows complete knowledge of the degree of effort made by knowing in what proportion or percentage speed is lost as repetitions are made within the series.

And this is important because the loss of speed is a highly valid indicator to estimate fatigue (Edman, 1992; Allen, Lamb, 8 Westerblad, 2008). This validity is based on the high relationship that exists between the loss of speed in the series and the loss of speed at a certain absolute load measured before and immediately after making the effort.

speed loss is a highly valid indicator to estimate fatigue

In turn, the loss of speed in the series can serve as a predictor of the degree of metabolic stress caused by training. Indeed, Sánchez-Medina and Gonzalez-Badillo (2011) carried out a study with 15 types of effort in the bench press and squat, with loads that could be done between 12 and 4 repetitions per series. These intensities correspond to mean relative intensities between 70 and 90% of the RM, although each subject did not really make the effort exactly with said intensities, but with the absolute loads with which they could do the marked repetitions.

The absolute loads used were those with which 12, 10, 8, 6 and 4 maximum repetitions could be done, which, on average, corresponds to relative intensities of 70, 75, 80, 85 and 90% of the RM. , respectively. The greatest effort with each load consisted of doing three series with the maximum number of repetitions possible (or one less than possible in the first series) and the least effort in doing three series with half the possible repetitions.

In addition, one or two more efforts were made with an intermediate number of repetitions. For example, with the load that 12 repetitions could be done, four efforts were made, performing three series of 12, 10, 8 and 6 repetitions in the series, which were represented as follows: 3×12(12), 3×10(12) , 3×8(12) and 3×6(12).

In total, 15 efforts were made with each of the exercises: bench press and squat. The valuation of The degree of fatigue generated with each effort was determined through the loss of speed with the load that could be moved at 1 m*s-1 before making the effort., as well as the loss of jump (really loss of execution speed) pre-post effort when the squat exercise was performed.

Before starting the squat training, the vertical jump test (CMJ) was performed after a specific warm-up. In both exercises, the warm-up began with progressive loads and when passing through the load that could be moved at approximately 1m*s-1, three repetitions were performed with it and the value of the load and the concrete average speed of the three repetitions were noted immediately after making the effort, the measurement was made again. jump (after the squat) and the load of 1 m*s-1 in both exercises.

Since the minimum load with which the efforts were made was approximately 70% of the RM, an approximate load of 60% was always used in the squat during the warm-up (load that moves approximately 1 m*s-1). and 45% in bench press (load that moves approximately 1 m*s-1).

In addition, after each effort, lactate and ammonium levels were measured. In figure 1 you can see the scheme of the execution of the efforts and the initial and final tests, in this case in the bench press exercise and with the load that could be done 12 repetitions: 3 series of 12 repetitions being able to make 12: 3×12(12).

In this case, the average speed before the effort with the load of 1 m*s-1 was 1.03 m*s-1. The subject continues his warm-up until he reaches the load with which he has to carry out the effort of the day: 3×12(12) and performs the 3 series at the maximum possible speed, with 5 minutes of recovery between series.

The speed with each repetition in the three series is represented by the three groups of central bars with a tendency to decrease. Immediately after (10-15 s) the last repetition of the last series, the load with which the speed of 1 m*s-1 was initially reached was measured again. In this case, the final average speed of the three repetitions was 0.71 m*s-1. The loss of speed, in this case 31.1%, reflects the quantification of fatigue.

The loss of speed, in this case 31.1%, reflects the quantification of fatigue.

Figure 1. Outline of the protocol followed in an effort of 12 repetitions, being able to do 12: 3×12(12), in the bench press exercise. Red bars, speed with the load of 1 m*s-1 before and after making the effort. Rest of the bars: speed with each repetition in the three series performed with the expected load (Sánchez-Medina and González-Badillo. Med. Sci. Sports 2011)

As a result of this study, high relationships were found between the loss of speed in the series and the loss of speed with the load that moved 1 m*s-1 before the effort, both in the bench press (r = 0, 97) as in the squat (r = 0.91), and with the loss of height (loss of speed) in the jump after the squat (r = 0.92). These results confirm that the greater the speed loss in the series, the greater the fatigue.

Later on, it will be analyzed more precisely how the degree of fatigue (loss of speed with the load of 1 m*s-1 and loss of jump) is dependent on the speed of the first repetition (real percentage of the RM) and of the series loss. Likewise, high curvilinear relationships were found between the speed loss in the series, the jump loss and ammonium [R2 = 0.89 in the bench press; R2 = 0.85 in the squat and R2 = 0.86 in the CMJ (figure 2).

Figure 2. Relationship between velocity loss and ammonium concentration with bench press (top figure) and squat (middle figure) exercises, and relationship between vertical jump losses after squat exercise and ammonium concentration (bottom figure). ). Note that from an approximate loss of speed in the series of 40% in the bench press, 30% in the squat, and 12% in the vertical jump, the ammonium concentration shoots up. (Sánchez-Media y González-Badillo, 2011)

An important and unique observation to date is that for an increase in ammonia to occur it was necessary to perform 1-2 repetitions more than half the number possible at any load and in both exercises. This can be seen in figure 3. The horizontal dotted line represents the baseline ammonium value. Only when more than half of the possible repetitions in the set are performed does the ammonium spike with an exponential trend.

For an increase in ammonium to occur, it was necessary to perform 1-2 repetitions, more than half of those possible, at any load.

This occurs in both the bench press and the squat, with very similar behaviors. Figure 2 also shows this trend.

Figure 3. Evolution of ammonium concentration in relation to the number of repetitions performed in the series with the bench press (left) and right full squat exercises. It is observed that for the ammonium to exceed the resting values, marked by the dotted line, it is necessary to do 1-2 repetitions, more than half of those possible in the series (Sánchez Medina and González Badillo, 2011). Figure taken from Sánchez-Medina’s Doctoral Thesis.

This behavior of ammonium could be at the base of the explanation of the proposals or hypotheses (based on experience and systematic observation, not on experimental data, when speaking of training to failure).) made in the 80s, with studies of the effect of non-maximal volumes (65 and 85% of the maximum achievable), or of training with half or less of the possible repetitions in the series of the National Field Hockey team of the 90s, or the first experimental studies that were designed in which one group did half the repetitions possible in the series and the other all the possible ones.

the appearance of ammonium above the basal values when lifting weights may mean that the effort is at the limit that should be reached.

And this is so because the appearance of ammonium above the basal values when lifting weights (in other types of exercises it may be different, and it certainly is) may mean that the effort is at the limit that should be reached.

The measurement of the loss of speed in each repetition and the degree of fatigue generated -measured through the loss of speed with the load of 1 m*s-1 and loss of jump- allow us to add much more precise information about this behavior. of ammonium than the simple count of the repetitions performed.

These speed losses in the series from which the ammonium is fired correspond to certain speed losses with the 1 m*s-1 load and height loss in the jump. The data with the following:

• With a loss of 40% speed in the bench press, ammonium is triggered (figure 2) and would correspond to a loss of speed of 17% with a load of 1 m*s-1.
• With a 30% loss of speed in the squat, ammonium is triggered and would correspond to a loss of speed of 12.5% with the load of 1 m*s-1.

With a 12% loss in jump height, ammonium shoots up and would correspond to a loss of speed in the series of 32% (Sánchez-Medina and González-Badillo, 2011).

It can be observed how the same fatigue generated when performing the squat, with 30 and 32% loss of speed in the series, is estimated in an equivalent way by the loss of speed with the load of 1 m*s-1 (12.5 %) and height in the jump (12%), respectively. This indicates that the loss of speed is an accurate indicator of fatigue, since its quantification before the same effort (loss of 30-32% of speed in the squat) can be done at different speeds, giving practically identical results.

In this case, the initial speed of 1 m*s-1 in the squat and the speed of the vertical saint have been used, which, on average, is performed at a clearly higher average speed, which could be approximately more than 1.5 m-s. * on average, which would be equivalent to a little more than 45 cm of initial jump.

If now the two variables used are analyzed: the loss of speed in the series and the number of repetitions performed, it can be confirmed that in the bench press exercise the loss of speed when half of the possible repetitions has been done is between 25 and 30% (González-Badillo et al., 2017) of the speed of the first repetition, that is, slightly below the loss caused by the ammonium shot, and that in the complete squat the loss of speed when doing half of the possible repetitions it would be approximately 15-20% (Rodríguez-Rosell et al., 2019), that is, also below the loss of speed caused by the increase in ammonia.

Therefore, if it is known what degree of effort (degree of fatigue) means each percentage of speed loss in the series, the application of speed as a training control method is very useful, it is probably the best procedure to estimate with high precision and immediately the training load.

ammonium concentration above quiescent values can be controlled by the loss of speed in the series

This load would be determined by the degree of fatigue caused by the joint effect of the volume and intensity used in training. Therefore, the ammonium concentration above the resting values can be controlled by the loss of speed in the series, since there is a close relationship between the loss of speed in the series and the percentage of repetitions performed (González-Badilo et al, 2017; Rodriguez-Rosell et al., 2019).

If, furthermore, it is known, through extensive practical experience, that doing half or less of the repetitions achievable in the series produces notable improvements in muscular strength and sports performance, it would not be very advisable to frequently exceed (in some cases it would never be necessary) half of the repetitions that can be done in a series. This practical experience has been reinforced by experimental studies in which it has been proven that losing 10-20% of the speed in the series, which is equivalent to performing half or less of the possible repetitions in the series, in the exercise of squat offers better results than losing 30-40%, which leads to a situation at the limit of ammonium increase (30% loss) or very close to muscle failure (40%) (Pareja-Blanco et al., 2017 ; Rodríguez-Rosell, Doctoral Thesis).

In addition to the relationship with ammonium, velocity loss also showed high positive linear correlations with lactate concentration: [r = 0.95 in the bench press, r = 0.97 in the squat, and r = 0.97 in the the jump (figure 4)].

Figure 4. Relationship between velocity loss and lactate concentration with bench press (upper figure) and squat (middle figure) exercises, and relationship between vertical jump losses after squat exercise and lactate concentration (lower figure). ). (Sánchez-Medina and González-Badillo, 2011).

Doing half or less of the repetitions achievable in the series produces notable improvements in muscular strength and sports performance.

If the regression equations corresponding to each of the relationships of the three exercises with lactate are applied, it is verified that before a 40% loss of speed in the bench press series, which is when ammonium is triggered, the lactate would be 5.3 mmol/L, in the squat, when ammonium increases, when losing 30% of the speed, lactate would be 7.2 mmol/L, and in the jump, when 12% is lost jump and the ammonium increase begins, the lactate would be 7.7 mmol/L.

As can be seen, the height loss in the vertical jump (12% jump loss and 32% speed loss in the squat) when ammonium is fired it corresponds to practically the same concentration of lactate than when ammonium is triggered by the loss of speed in the series in the squat exercise (30%).

Which corresponds to the behavior observed when analyzing ammonium. Therefore, ammonium begins to rise when lactate is 5.3 mmol/L in the bench press and 7.2 mmol/L in the squat (figure 15.14). From this relationship it can be deduced that, although it is not the most practical and viable option, if one wanted to analyze the possible behavior of ammonium without measuring it, given its greater difficulty and price, one could measure lactate to predict at what moment the lactate begins to be triggered. ammonium.

Although, naturally, the most precise, economical, easy-to-perform procedure and with immediate information is the control of speed loss in the series.

Figure 5. Relationship between lactate values and ammonium firing in bench press and squat exercises (Sánchez-Medina and González-Badillo, 2011)

There were also high relationships between stalling and testosterone (r=0.83), growth hormone (r= 0.82), and insulin (r= 0.88). These relationships increased for ammonium (p = 0.94-96) and lactate (p = 0.98) when Spearman’s rank correlation coefficient was used (data from the same unpublished study). All these relationships indicate that the higher the speed in the series, the greater the mechanical, metabolic and hormonal stress tends to be, the greater the degree of effort generated.

the greater the speed loss in the series, the greater the mechanical, metabolic and hormonal stress tends to be, the greater the degree of effort generated.

The question that should be asked as a result of this knowledge is what should be the optimal loss of speed in each case. This question, of course, does not have an easy answer, but being able to ask it, and having the appropriate mechanical and physiological data available to try to find an answer, is already a great advance.

In the next articles, useful studies for the practice of training and that provide answers to many of these questions will be reviewed.

Conclusions

From the above it can be deduced that the knowledge of the relationship between the loss of velocity in the serle and the loss of velocity with the load of 1 m*s-1 and the height of the CMJ, as well as the metabolic stress allows us to conclude the following:

• The fatigue caused by a training session of three sets with loads that allow you to do between 12 and 4 repetitions per set depends on the percentage of speed lost in the set.
• The training load can be quantified by the loss of jumping capacity and the loss of speed before a determined load (mass) in each session.
• The relationship between the loss of jump and the loss of speed could be verified before a determined load per session and the effect of the training.
• The loss of velocity in the series with the load of 1 m*s-1 and in the CMJ are accurate estimators of the metabolic stress caused by the training session.
• Depending on the metabolic stress generated, a subject should not lose more than 20-35% (depending on exercises) of the speed of the first repetition in the series:
  • Performance is probably not better if you lose a higher percentage of speed. In the squat exercise, an average loss of speed in the set of 10-20% offered better results than a loss of 30-40%.
  • In the bench press exercise, a mean loss of 27.7% outperformed losing 53.3% (unpublished laboratory data).

a subject should not lose more than 20-35% (depending on exercises) of the speed of the first repetition in the series

• If you do a training session of three sets with any load between those with which you can perform between 12 and 4 repetitions per set, performing a range of repetitions between half and the maximum of the possible repetitions in the series, ammonium increases exponentially from a loss of speed of 40% in the bench press and 30% in the squat. In the case of the vertical jump, the increase in ammonia occurs when a pre-post effort jump loss of 12% is reached.
• As a practical application of synthesis, it is suggested:
  • People who train for improved health should not do even half of the possible repetitions in the series.
  • Most experienced athletes with medium-high strength needs will probably be able to perform at most half or 1-2 repetitions more than half of the possible ones. Although we also estimate that athletes with lower strength needs probably, even if they are very experienced, do not need to perform even half of the possible repetitions in the series at any time.

In previous articles it has been seen that there are a series of determining factors of the force that a muscle or group of muscles can generate. Afterwards, the influence of muscle activation as the cause of a series of effects that translates into certain structural and neural transformations has also been analyzed, which give rise to the fact that this muscle activation constitutes what is understood as training.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

Well, whatever the way in which muscle activation is carried out, whether it is correctly or not, training depends on a series of factors, whether or not the training programmer is aware of them, or Whether you take them into account or not, they are the determinants of the effect produced by the training.

These factors of sports training are three.

1/3 Factors of sports training: the speed of the first repetition.

First indicator of the character of the effort (CE) and the effort index (IE). Determinant of relative training intensity

Justification.

• Because it determines the percentage of the current RM with which the subject trains: real effort that represents the first repetition
• Because given the same speed, this percentage is practically the same for all people
• Because it starts from the assumption that even if the RM value changes, the speed with each percentage is very stable. Which is sufficiently proven.

That is, even if a training programmer does not know or does not want to know that when he performs the first repetition of a set, the speed at which he executes it determines what relative intensity he is training, that speed will determine the effect of the training, because it represents a highly relevant variable of training and its effect.

If the programmer ignores this reality and programs a percentage based on a 1RM value obtained at some point, it is already known that there is a high probability that the athlete or trained person is not training with the intensity (percentage in this case) that the programmer thinks.

But without a doubt, even in this case, what will determine the effect of the training will continue to be the speed at which the load has been moved in the first repetition, which, in this case, would represent a percentage unknown to the programmer (cases are discarded). in which the programmers indicate that the loads do not move at the maximum possible speed).

The same situation would occur if the programmer proposes that you train with a load with which you can do a certain maximum number of repetitions in the series (XRM or nRM).

Everything said in the previous paragraph is valid, but with the added peculiarity that in this case the subjects, with a high probability, would train with different relative intensities. In this case, the speed control would “come to the rescue” and could determine with what actual relative intensity they trained, even though the programmer thinks it was the same for everyone.

2/3 Factors of sports training: The loss of speed in the series with respect to the first repetition

Second indicator of the character of the effort (CE) and the effort index (IE).

Justification: Because it indicates the degree of fatigue for the same speed of the first repetition and equalizes the effort for all trained subjects. That is, because although the number of repetitions performed in the series is individual (and different) for each speed of the first repetition of a series, the percentage of repetitions performed before the same loss of speed in the series is approximately the same, and for this reason, as has been verified, there will be a very similar degree of fatigue.

With the two sports training factors described, the effort made by the subject has been defined, since its product gives rise to the IE. Index that presents a high validity as an indicator of the fatigue generated by the training.

Unfortunately, if the programmer does not know the importance of the loss of speed in the series, the effect of the training will be produced with different efforts for each subject, unknown to the programmer. If the maximum number of repetitions in the series is programmed for all the subjects, the subjects will train with different intensities in most cases, but the influence of the loss of speed in the series will be present as a “factor” of the training effect. and it will be responsible, to a large extent, together with the speed of the first repetition, of the training effect.

Naturally, the programmer will not have information about what load could have produced the effects of his training, but whatever they are and whatever the reference for programming the repetitions in the series, the effect will depend on the loss of speed in the series, and , more properly, of IE.

3/3 Sports training factors: Exercise in question.

Justification:

Each exercise has a different speed for each percentage loss of speed in the series (González-Badillo, 2000). This is because the speed with each percentage depends on the speed with which the RM is reached, which is different for each exercise (González-Badillo, 2000).

This own speed determines the characteristics of the exercise in relation to the loads and frequencies that can be used. It is reasonable to think that doing a full squat exercise does not produce the same degree of fatigue as an arm push exercise. In addition, the speed of the RM means that some exercises can be trained with higher relative intensities than others.

A clear example is the comparison of the squat and the power clean. Certain athletes would not need, and should not, do a full squat with loads greater than 80% of the RM even at the end of their sporting life, even with extensive experience in strength training.

However, these same athletes can train with intensities of 75-80% of the RM in a clean force almost from the first day of training, once they have learned a fairly acceptable technique, and later they could reach intensities of 85 and even 90% of the RM in the exercise, if the technique was good.

Also, a clean workout can be done any time close to competition, and is highly unlikely to interfere with specific performance: it could be done up to a few minutes before some competitions.

These different possibilities of the exercises are related to the speed of the respective RM. A high speed of the RM acts as a “safety” of positive effect with minimal interference with any specific exercise.

In this case, the problem would come from not knowing that the speed of the RM is determinant of the characteristics of the exercises. This lack of knowledge can lead to the training being programmed with the same intensities, and even with the same repetitions per series, with exercises with very different speeds typical of RM, which can lead to proposing excessive intensities in some exercises or useless intensities. in others.

This article reviews the differentiation between central and peripheral fatigue. For a long time, fatigue has been mainly related to factors dependent on what “happened” in the muscle, without taking much into account the previous mechanisms.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

SUMMARY

• Central fatigue appears both in short, high-intensity efforts (strength exercises) and in prolonged efforts of clearly lower absolute intensity (resistance).
• The feeling of fatigue is greater with prolonged efforts and appears first in the Central Nervous System.
• Peripheral fatigue appears when the force decreases when an electrical stimulation is applied to an exercised muscle.

The little importance attributed to the central factors could have been due to the simplification of applying to the conscious human subject the results on force limitation obtained in isolated muscular preparations and, generally, deprived of their innervation, and to the methods to measure the amount of the central influence on the muscles, which have not been technically rigorous and, therefore, the results are easily criticized and not considered

When it has been possible to measure changes in the central nervous system (CNS) during exercise, these have been mainly oriented towards the demonstration that they can cause a strength deficit (Gandevia, 2001). Central fatigue is manifested by a progressive loss of voluntary activation or a decrease in the neural stimulation necessary for the execution of an exercise, which translates into a decrease in the maximum force applied.

Central fatigue appears both in short, high-intensity efforts (called strength exercises) as in prolonged effort of clearly lower absolute intensity (called resistance exercises) but the feeling of fatigue is greater in prolonged efforts, and the mechanisms responsible for both types of fatigue are different. Fatigue manifests itself first in the CNS and it itself tries to compensate for it with increased arousal and the activation of a greater number of motor neurons, involved in the control of muscle activation, although there is a degree of fatigue from of which the CNS reduces activation to prevent impaired homeostasis and muscle damage.

Fatigue has a significant core component.

Fatigue has a significant central component. If, in a situation of fatigue, a stimulus that does not depend on the CNS is applied and a recovery of strength occurs, the central component is evident. In the first studies, the central effect was verified by the fact of recovering the force when opening the eyes when a situation of almost total fatigue had been reached (MOsSO, 1904). Subsequently, the verification that fatigue has a central component is carried out through the interpolation of electrical stimuli during voluntary contractions.

If, when force production decreases during a maximal voluntary contraction, direct electrical stimulation is applied to the muscle fibers and force increases again, this is evidence that fatigue had a central component. If in the same situation the force does not increase, the fatigue is central and peripheral.

If muscle activation is measured through an electromyogram (EMG) and the frequency of action potentials and force decrease, fatigue has an important central component, and if the frequency of action potentials does not decrease and the force does, fatigue is mainly peripheral in origin.

The central type effect is also manifested by the specificity of fatigue. In the figure below it can be seen that the effect of training on fatigue manifests itself in a specific way depending on the type of training performed. When training with one leg, the positive effect on fatigue occurs only when the effect is measured with one leg, not with both. The opposite occurs when training with both legs.

Specificity of the effect of training on fatigue (Rube and Secher, 1990; in Moka, 2002).

Fatigue in different types of efforts can be characterized and measured in different ways depending on the duration and intensity of the efforts. In this entry we analyze the various factors that cause fatigue according to the duration of the effort.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

SUMMARY

• In short efforts the performance is highly dependent on the oxygen consumption capacity of the subject (VO 2max)
• In efforts of up to 30 minutes, the lactate threshold point (anaerobic) is decisive.
• In efforts that last more than an hour, fatigue is highly associated with the depletion of muscle glycogen stores.
• A good metabolic indicator of stress caused by exertion is the blood lactate concentration.
• The loss of execution speed is a faithful reflection of the fatigue state of the subject.

short duration efforts

From efforts as short as 100 meters of sprint (10-12 s) there are already losses of speed (decrease in performance) involuntarily, which is an indicator that during the test there is a phase in which it manifests itself. fatigue as a loss of capacity to produce force in the unit of time.

The causes of fatigue in this type of effort are multiple, but of all of them the decrease in availability is probably the most important. Considerable increases in the plasmatic concentration of hypoxanthine, ammonia and uric acid have been observed in this type of effort. These results indicate that there have been difficulties in synthesizing ATP via ADP + CP and that energy production has been resorted to through the ADP + ADP = ATP + AMP reaction. This indicates that you there has been significant metabolic stress in the muscle cell, which can be associated with injury to said cell, and the loss of purines that can negatively influence the phosphagen reserves of the muscle, which has repercussions in the reduction of the muscle’s capacity to produce energy quickly in the following days.

Metabolic stress on the muscle cell influences the muscle’s ability to produce energy on successive days.

It does not appear that acidosis is a determining factor in these cases. In addition to what has been indicated, this fatigue is associated with a decrease in the activation of motor units in the excitation-activation process and an increase in Pi and ADP. In other short efforts such as throws, jumps, Olympic lifts and the like, fatigue is related to the same mechanisms, but with less influence from metabolic factors. If the efforts are somewhat longer (15-40 s), the participation of the phosphagen pathway to provide energy is coupled in a very important and decisive way with the ability to rapidly provide energy through the anaerobic glycolytic pathway. For this reason, in this type of effort, all the factors responsible for fatigue in the previous type of effort are present and increased, plus those derived from a drop in pH.

Therefore, it is likely that the concentration of metabolites, the alteration of calcium transport (excessive accumulation of myoplasmic calcium), the accumulation of Pi and the excess of extracellular potassium are also present as responsible for fatigue in this type of effort. The same causes of fatigue occur in efforts that last about a minute, but the fundamental difference is in a greater influence of the pH reduction, which practically reaches its maximum in efforts of this duration. High acidity, in addition to the previously described effects on the cross-bridge cycle, acts on cionide channels (which mainly govern membrane excitability), depolarizing the membrane and leading to the inactivation of sodium channels, essential for the generation of action potentials, at the end of the effort.

In this situation, the hydrogen ions themselves act by priming the working speed of the mitochondria, shifting the burden of maintaining the energy supply to the mitochondrial aerobic pathway. Given the low rate of ATP generation from the mitochondria compared to the anaerobic glycolytic pathway, the rate is clearly reduced at the end of the effort. These same causes could be applied to efforts that last up to three minutes, with a greater dependence on the ability to provide energy aerobically.

long-lasting efforts

When the efforts last between 5 and 10 minutes, performance is highly dependent on the subject’s oxygen consumption capacity (VO 2max), but there is also significant phosphagen depletion and high acidity. Therefore, in this type of effort, fatigue may depend in part on the processes related to phosphagen depletion, and to a large extent on the ability to produce energy aerobically (power and maximum aerobic capacity), but also on the power and anaerobic capacity and problems related to the reduction of pH.

In efforts of up to 30 minutes, the lactate threshold point (anaerobic) is decisive.

In efforts that last up to approximately 30 minutes, the aerobic power of the subject is still very important, but the speed at the lactate threshold point (called anaerobic) seems to be more decisive. Therefore, fatigue may be closely related to the ability to capture, transport, and use oxygen for the oxidation of glucose by the aerobic route, but especially to speed or power in conditions of suprathreshold lactatemia. In the final sprint of some tests, the depletion of muscle CP reserves or excessive muscle acidity may influence. Another factor that may be related to fatigue is high body temperature, although this would be more relevant after one hour of effort.

In efforts that last more than an hour, fatigue is highly associated with the depletion of muscle glycogen stores., and, therefore, although all the factors indicated for the previous efforts are present to some extent, the availability of glycogen stores could be a factor causing the fatigue of this exercise. In addition, glycogen depletion is associated with fatigue as it may cause decreased calcium release from the sarcoplasmic reticulum and consequent effect on muscle activation, although the link to low glycogen is uncertain. with failure of calcium release (Allen et al., 2008).

In efforts that last more than an hour, fatigue is related to the depletion of glycogen stores.

Other factors such as an excess of ammonium, an increase in muscle Mg concentration, an excessive increase in body temperature or an insufficient capacity to use lipids to produce energy could also be the cause of fatigue in this type of effort.

Efforts to overcome external loads

As we have indicated when discussing the concept of fatigue, in addition to a decrease in force production, another aspect of muscle performance such as speed of shortening is also an indicator of fatigue (Allen et al., 2008; Edman, 1992). If we take into account that the loss of speed before the same load is a direct consequence of the reduction of the force applied to said load, we must admit that the loss of speed is a faithful reflection of the state of fatigue of the subject.

It is evident that when a subject is visually perceived to be “tired” (fatigued), we detect it by the loss of execution speed, whatever the activity the subject performs: displacing an external load or displacing his own body. Speed ​​also has an advantage over force as an indicator and quantifier of fatigue, and that is that it can be measured more easily and accurately than force, and also in competition and training gestures or actions.

The loss of speed in efforts to overcome external loads is a faithful reflection of the state of fatigue.

Therefore, when a gesture has to be performed at the maximum speed possible, knowledge of the loss of speed may be the best procedure to determine the degree of fatigue in which the subject is found during and after the effort. These reasonings lead us to propose that when training is carried out through the displacement of external loads, the loss of speed in the series is an accurate indicator of the fatigue (and the load) that carrying out the exercise supposes for the subject.

Given this premise, the validation of the loss of speed in the series as an indicator of fatigue is achieved if there is a high relationship between this loss of speed during and at the end of the effort, and the reduction in contractile capacity, which could be quantified. also through the loss of speed with respect to the speed reached when displacing the same load prior to the fatiguing effort. Specifically, as mechanical indicators we can use two exercises:

1) the loss of speed before the same load, which in our case is the maximum load that can be moved approximately 1 m*s-1, and

2) the loss of jump height (which is really also a loss of speed) after the effort.

To this main validation, the relationship with indicators of the degree of stress caused by the effort could be added, which could contribute to a better knowledge of the type of effort made and the possibility of replacing the measure of certain metabolites by the loss of speed (concurrent validity ). As metabolic indicators we consider the changes in the concentration of lactate and ammonium. Indeed, a good metabolic indicator of stress caused by exertion is the concentration of lactate in the blood.

Lactate production is related to the difference between the motor command of the central nervous system and the actual mechanical execution of the muscle. The greater the difference between what is commanded by the central nervous system and what is executed by the muscle, the greater the lactate production will be. In addition, lactate production, far from being detrimental to the functioning of muscle fibers, is actually an essential component to improve muscle fiber excitability by blocking chloride channels (Ribas, 2010; González-Badillo and Ribas, 2002). As shown later, the relationship between the lactate concentration and the loss of speed of movements executed at maximum speed is excellent, such that the greater the loss of speed, the greater the production of lactate by the muscle fibers (Sánchez -Medina and González-Badillo, 2011; Rodríguez-Rosell et al., 2018).

In this article, the importance of the execution speed of the first repetition for the dosage, control and evaluation of strength training is exposed in an orderly manner in order to give the opportunity to become aware of the repercussion of the appropriate application of this variable in the development of everything related to strength training.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

SUMMARY

• Speed ​​control comes to overcome the series of inconveniences presented by the use of RM and XRM or nRM in the dosage of training and in the evaluation of its effect.
• It has been confirmed that each percentage of 1RM has its own speed for each exercise. This speed is very stable for the same person when their performance changes, and very similar between people, even when the level of performance between people is very different.
• If the average or average maximum propulsive velocity with which a mass displaces can be measured, by applying these equations we can obtain the percentage of the RM that said mass represents.
• The speed of the first repetition of the series serves to determine with what relative load the subject is training, as well as to determine what has been, and continues to be, the effect of training each day, what has been the evolution of the maximum intensity used every day, and what has been the pre-post training effect…
• The speed with each percentage is very similar between people with a very different level of performance.

Indeed, faced with all these inconveniences, it is necessary to find an appropriate solution. If the training schedule is nothing more than the expression of a series or ordered succession of efforts that are dependent on each other, and the effort is the actual degree of demand in relation to the current possibilities of the subject, which represents the nature of the effort, the appropriate solution will be to be able to measure with high precision the character of the effort. This is achieved if it is known:

• The Degree of Effort that represents the first repetition of a series.
• The Degree of Effort that represents the loss of speed within the series.

This article will deal with these two factors as key elements of the quantification, dosage, control and evaluation of the training load and its effects.

The speed with each percentage of the RM and its stability. Degree of Effort that represents the first repetition of a series

A few years ago Professor González-Badillo wrote: “if we could measure the maximum speed of movements every day and with immediate information, this would possibly be the best point of reference to know if the weight is adequate or not”… ” You could also record the maximum speed reached by each lifter with each percentage, and based on this, assess the effort” (González Badillo, 1991, p. 172). Currently, it can be affirmed that these hypotheses-proposals have been confirmed.

In the year 2000 these authors presented the first data in relation to speed with each percentage (González-Badillo, 2000). Subsequently it has been confirmed that each percentage of 1RM has its own speed. This speed is very stable for the same person when their performance changes, and very similar between people, even when the level of performance between people is very different (González-Badillo & Sánchez-Medina, 2010).

Therefore, throughout the approach to the application that has the knowledge of the speed of the first repetition under an absolute load, it is assumed that, although the value of 1RM can change between different days, the speed at which that each percentage of the MRI is performed is very stable.

For example, in the bench press exercise, whenever a well-executed progressive test is carried out until reaching RM and we verify the relationship between the percentages represented by the different displaced masses and the speeds at which they have been displaced, we found a very high fit to a second degree polynomial trend curve.

This kind of high fit has occurred in all the well-performed tests that have been carried out by the authors in the last 25 years. It must be taken into account that the concentric phase in the bench press test must be performed after a brief pause (1-1.5 s) after the eccentric phase, with the support of the bar on the chest or on a support .

The concentric phase must be performed without countermovement and the speed of execution must be the maximum possible before each mass. One should start from low relative intensities, equivalent to 15-20% of the RM. A high value of the R2 allows estimating (applying the corresponding regression equations) the speed with any percentage of the RM with a very small error.

The relationship between the different percentages and their corresponding mean propulsive velocities in the bench press exercise is expressed in Figure 1. The series of points that resemble a line—that appear at 100% MR height, rounded by a red circle, are the MR velocity values ​​for each of the subjects. Naturally, there are subjects whose average MR speed is above average and others below average. it is not possible for all subjects to perform their one-repetition maximum at the same speed.

Figure 1. Relationship between the RM percentages and their corresponding mean propulsive velocities. The 1596 data from 176 subjects are practically within the De 95% interval, with an R2 of 0.98 and an estimation error of 0.06 (González-Badillo and Sánchez-Medina)

These differences in the speed of the RMs are responsible for the points going slightly above the mean line or below. That is, the speed of each percentage tends to depend on the speed with which the RM was reached. If with the data of figure 1 the average propulsive velocity (VMP) is considered as an independent variable, we obtain an R2= 0.981; an estimation error of 3.56% and the following regression equation %1RM = 8.4326 * VMP2 – 73.501 * VMP + 112.33, where VMP is the mean propulsive velocity.

If we took the VM speed as a reference, not the VMP, the data would be the following: R2 = 0.979; an estimation error of 3.77% and the equation: %1RM = 7.5786 VM2— 75.885 VM + 113.02, where VM is the average speed of the entire route.

These equations make it possible to estimate with considerable precision the percentage represented by any absolute load once the VMP or MV at which it has moved is known, provided that the speed of movement has been the maximum possible for the subject.

It is preferable to take the average propulsive speed as a reference, since it better represents the true performance of each subject, by eliminating from the measurement the braking phase that occurs when the loads are medium or light. But if the speed meter used does not register this speed value, the average speed can be used, but taking into account that the speeds with each percentage will be slightly lower under light and medium loads if MV is measured than if MP is measured.

If the average or average maximum propulsive velocity with which a mass displaces can be measured, by applying these equations we can obtain the percentage of the RM that said mass represents.

Once you know the percentage that a given mass represents, you can estimate the RM at any time without the need to measure it, although knowledge of the RM is not necessary to dose the training or to assess its effect. Unfortunately, there are many “studies” that have been devoted to estimating the RM in some exercises, when really the value of the RM, when talking about the training load, practically and totally loses its “bad” application if we handle it properly the information that the knowledge of the speed of execution offers us.

According to the regression equation shown in figure 1, the average propulsive velocity that would correspond to each percentage of the RM is presented in figure 2.

Figure 2. Mean propulsive velocity corresponding to each percentage of the RM in the bench press exercise (González-Badillo & Sánchez-Medina, 2010)

It is very important to verify that the relationship between speed and load is stable, that is, if these values ​​remain very similar when the subjects change their performance, since this is the basis for applying the speed of the first repetition of the exercise. series for reference.

The speed of the first repetition of the series is used to determine with what relative load the subject is training., as well as to determine what has been, and continues to be, the effect of training each day, what has been the evolution of the maximum intensity used each day, and what has been the pre-post training effect…

The training effect is assessed by speed changes at the same absolute loads at any time, which can be before and after a training period or in each of the training sessions. All this constitutes part of the maximum and best information that a coach can have to know what he is doing and improve his training methodology.

The speed of the first repetition of the series is used to determine with what relative load the subject is training.

In this sense, a series of data are provided that serve as a reference to confirm that, indeed, the speed values ​​with each percentage are very stable, even if the performance of the subjects changes and even if the subjects are of a very different level of performance. . A first example of this stability is presented in figure 3, in which the results of two measurements of the speeds are compared with each percentage of the RM in the bench press exercise.

first study: analysis of velocity in the bench press exercise

The values ​​for the year 2010 are the same as those in Figure 2. These values, which were recorded in the years 2006-2007, were obtained with subjects other than the participants in the 2014 study, whose data were recorded in 2013-14, 6-7 years apart. It can be seen that the speed values ​​with each percentage are practically the same. These data help to confirm that the speed with each percentage remains stable, even though the data is obtained with completely different samples.

Figure 3. Velocity with each percentage of the RM in the bench press exercise in two different groups of subjects and several years apart in the recording of the data. It can be seen that the differences (upper part of the figure) in the speeds do not exceed 0.02 m-s-1. (Figure by Sánchez-Medina).

Continuing with the examples, in the study by González-Badillo and Sánchez-Medina (2010), carried out with the bench press, it was verified that after a training period of an average of six weeks, 56 subjects, who improved as averaged 9.3% of their RM on the bench press, they kept pretty much the same velocity with each percentage. These data allow us to confirm that not only each percentage of the RM has its own speed, but that this speed is very stable when the performance is modified.

Not only does each percentage of the RM have its own speed, but this speed is very stable when changing performance.

Table 1 shows the average speed values ​​with each percentage before and after the training of the 56 subjects. The maximum difference is 0.01 m*s-1. It should be noted that these subjects trained according to their criteria, without any instruction, which means that the training sessions must have had very different characteristics.

Tabla 1. Mean propulsive velocity and standard deviation with each percentage of the RM in the bench press in 56 subjects before (T1) and after (T2) a training period of 9 weeks on average (González-Badillo & Sánchez-Medina, 2010).

From the individual data of these 56 subjects we can extract additional information that allows us to continue reinforcing the stability of the percentage-speed of execution relationship. Several representative cases are discussed below.

Figure 4 shows the data of one of the subjects, who was very expert in training the bench press exercise, and who clearly improved his 1RM: 14.8%. If we look at the figure of test 2, T2 (red line), apparently, the speeds with each percentage are lower than those of test 1, T1 (blue line). This would go against the hypothesis that holds, but these data are not comparable, so they really do not go against the hypothesis.

The explanation is in the speed with which each RM has been achieved. In T1 the velocity was 0.17 m*s-1, while in T2 it was 0.06 m*s-1 (both values ​​in the red circles at the bottom of the figure). These two RMs cannot be compared, because they have been achieved at clearly different speeds, and, therefore, their speeds with each percentage cannot be compared either: the lower the speed with which the RM is achieved, the lower the speed with each percentage.

If the difference between the speeds of the RMs is equal to 0.03 m*s-1, we can already begin to observe a tendency to be lower than the speeds corresponding to the RM reached at a lower speed, and if the differences are greater than 0.03 m*s-1, the two RMs should no longer be compared.

Figure 4. Evolution of speed with each percentage in a subject who exceeds his result by 14.8% but performs his RMs at very different speeds (see text for further explanation).

It must be taken into account that the fact that the two RMs should not be compared is not due to the fact that one of them is considered a “true” RM and the other is not, since both are within the velocities of the RM of this exercise, whose average value may be around 0.17-0.18 m*s-1 (González-Badillo, 2000; González-Badillo and Sánchez-Mediná 2010), but to the fact that there is a high difference between them .

However, despite the fact that in T1 the speed of T2 almost triples, the differences in speeds with each percentage do not exceed, in the worst case (low percentages), 5% of the RM since the difference in speed each 5% is 0.08-0.09 m*s-1, a difference that is not exceeded in any of the percentages calculated, from 30 (0.09 m*s-1 difference) up to 95%.

Conclusions of the first study

As a result of the analysis of this case, at least the following practical applications can be deduced:

1) MRIs whose measurement speeds are greater than 0.03 m*s-1 cannot be compared, although in extreme cases such as the one we are presenting, in which the speed of the MRI is tripled, the effects do not go beyond one difference of 5% of the MR for the same speed of the same subject,

RMs whose measurement speeds are greater than 0.03 m*s-1 cannot be compared,

2) given the high probability that two RM are measured at different speeds, it is not advisable to ever measure the RM (it can be estimated, if necessary for something, as we will see in another section) and

3) only by measuring the speed with which the MR is reached, it is possible to have the necessary information to avoid the errors made with high frequency when measuring this variable.

Here we have to remember that the true RM will never be known, but some RMs can be considered as “true” or representative of the true RM when measured at velocities of their corresponding RM values. The more the measured speed (always higher speeds) deviates from the MR values ​​of an exercise, the more “false” is the RM measurement. This, once again, can only be known if the speed with which the exercise is performed is measured.

The errors to which we refer in the practical application 3) refer to the fact that most of the changes, such as the improvement or worsening of the results observed when measuring 1RM, are false, because if a subject, for example (it is a case real), lifts 82 kg in T1 and 92 kg in T2, it can be concluded after doing the calculations, that the subject has improved his mark by 12%.

But if one takes into account that this subject did the MRI of T1 at 0.33 m*s-1 (real data) and that of T2 at 0.2 m*s-1, the conclusion is false, because if the subject could have done the MRI at T2 at 0.2 m*s-1, it could also have been done at a very similar speed (0.2 + 0.02 m*s-1) at T1.

This would mean that he could have lifted a weight greater than 82 kg, then the improvement has not been, by any means, 12%. As an example, and making a few small calculations, if we suppose that the T1 would have done it at the same speed as the T2, at 0.2 m*s-1, and taking into account that every 5% the speed change is 0.08 m*s-1, the subject in T1 would have lifted approximately 88 kg, 8% more, given that the difference between T1 and T2 is 0.13 m*s-1.

Therefore, the improvement would have been approximately 4-5%, far from the apparent 12%. This example shows one more of the important applications that measure the speed of my execution has, although this application is better not to use it, because the RM should never be measured.

second study

A new example is shown in Figure 5. This subject improved his result by 11.8% and the velocities with the MRI presented a small difference of 0.02 m*s-1. As can be seen, the velocities with each percentage remained practically stable, with a maximum difference of 0.02 m*s-1, that is, the equivalent of a maximum difference of 1.25% of the RM with respect to T1.

Also, in this case, the speed in all percentages tended to increase slightly, so it could be said that the subject slightly improved (because the change can only be very small) his strength deficit. This slight improvement in speed can be explained because the subject, after his experience in doing the tests, decided to train by performing each repetition at the maximum speed possible, when previously he did it slowly voluntarily.

Therefore, it is confirmed that despite a considerable improvement of almost 12% (in this case we can say that it is real), the speeds with each percentage remain stable.

Figure 5. Evolution of speed with each percentage in a subject who exceeds his result by 11.8% and performs his RMs at very similar speeds

Figure 6. Evolution of speed with each percentage in a subject who does not exceed his result and performs his RMs at very similar speeds

Figure 6 shows an example of a subject who did not improve his result and that the speeds with each percentage were practically the same in both tests, although T2 was performed at a speed of 0.03 m*s-1 higher than the from T1.

But, precisely, this small speed difference could explain, on the one hand, why the speeds in T2 are minimally higher (0.01-0.2 m*s-1), and on the other, that it really cannot be said that the subject It did not improve its performance at all, since it improved speed by 0.03 m*s-1 with the same load (110 kg). This assessment can only be done if the speed of execution is measured

Figure 7 shows the case of a subject who improved his RM by 7.9%, who performed his two RMs at the same speed, but the speed with each percentage up to 75% of the RM tended to decrease. This was the only case, out of 56, that departed from what we have been maintaining. But when consulting the subject about his way of training, he stated that he trained slowly voluntarily.

Training slowly voluntarily may tend to proportionally decrease performance with loads moving at high speed and thus increase the strength deficit under these loads.

This way of training may tend to proportionally decrease performance with loads that are moved at high speed and thus increase the strength deficit in the face of these loads. Despite this circumstance, it can be observed that the decrease in speed with light loads did not exceed 0.06 m*s-1, which means that, in the worst case, the maximum difference in speed with each percentage in T2 with respect to T1 it was equivalent to 3.7% of the OR.

Figure 7, Evolution of speed with each percentage in a subject who exceeds his result by 7.9% and performs his RMs at the same speed.

In Table 2, made up of two groups of data, with a total of 20 subjects (the first 20, by random order, in the list of 56 subjects who repeated the tests) we can see the speed at which they reached their RMs. in tests 1 and 2, the average speed of the percentages from 40 to 90% of the RM, the maximum and the minimum difference obtained in the set of these percentages and the change in performance.

It is observed that the average speed from 40 to 90% follows the same trend as the difference between the speeds of the RMs. Only in the cases of JG and PC subjects, the maximum difference in some percentage is equivalent to a 5% difference with respect to the RM.

It can be seen that there are 12 cases of improvements ranging from 8.3 to 21.23% with an average of 13.9%, in which the maximum difference in speed with the percentages from 40 to 90% is 0.05 m*s-1 in the two subjects mentioned above (JG and PC), one case with 0.04 m*s-1 (V) and the rest with 0.03 m*s-1 or less. This data set again reinforces the stability of the speed of each percentage, even if there are important changes in the performance of the RM.

Table 2 Velocity values ​​with the RM (vel_RM), average velocity of the velocities with the percentages between 40 and 90%, maximum (max_diff), and minimum (min_diff) velocity difference with each percentage between tests 1 and 2 and change in performance (Change_RM) of the first 20 subjects in the list of 56 who repeated the tests.

Table 3 shows the speeds with the RMs, mean speeds from 40 to 90% of the RMs, differences in the speed with the RM and the differences between the mean speeds with the set of percentages in two tests for the same subjects included in Table 2. Taking the set of data included in the yellow columns, it is possible to calculate the relationship between the differences in the speed of the MRI and the differences in the average speed of

Tabla 3. Speeds with the RMs (Ve_1RM), mean speeds of the percentages from 40 to 90% of the RMs (Vel_mean_%), differences in speed with the RM (Dif_V_1RM) and the differences between the mean speeds with the set of percentages in the two tests (Dif_V_mean) of the same subjects included in Table 2.

Figure 8 shows the relationship between the differences in the speed with which the RMs were achieved (axis X) and the differences in the mean speed in the percentages of the RM from 40 to 90% (axis Y).

It can be seen that 12 of the 20 cases are found in the positive quadrants of the coordinate axes, which are the ones that correspond to the trend that indicates that the speed of the MRI determines the speed with each percentage, that is, the higher is the speed of the RM the greater the speed tends to be with each percentage.

There are three cases in which the velocities with the MRI were the same (points that coincide with the Y axis) and the velocities with the percentages changed minimally, between 0.03 and 0.02 m*s-1.

A case in which, having produced a decrease in the speed of the MRI in T2 by about 0.07 m*s-1, the average speed of the percentages was identical (point located on the X axis). This case can be considered as an example of a subject improving his strength deficit: although a lower MR speed should correspond to a slightly lower speed with each percentage, the subject maintained a speed.

There are two cases in the lower negative quadrant in which, having slightly increased the speed with the MR around 0.02 m*s-1, the speed with the percentages decreased by 0.02 m*s-1, which suggests that it was produced a minimal increase in strength deficit.

Finally, there is a case in the upper negative quadrant in which a subject who performed his MRI speed at a slower speed (0.02 m*s-1) at T2 slightly increased speed with percentages (0, 01 m*s-1).

As can be deduced, the stability of the speed with each percentage is ratified. The changes are minimal and the trend between the speed with the RM and the speed with each percentage is fulfilled in a remarkable way.

Figure 8. Relationship between the differences in the speed with which the RMs were achieved (axis X) and the differences in the mean speed in the percentages of the RM from 40 to 90% (axis Y).

It must be taken into account that the subjects cannot behave like perfect “machines”, but that they respond in a way that is not exactly the same before a series of progressive loads when trying to perform a 1RM test. This means that under absolute load the performance is not exactly the same as under the immediately higher absolute load.

That is to say, if a subject achieves a certain speed at an absolute load, not always at the load immediately above, which will represent a certain percentage increase, he will respond by reaching exactly the speed that would correspond to that percentage increase in load. This can cause the subject’s force or load-velocity curve to adjust more or less to his true performance capacity, giving rise to small deviations from the model that represents the population to which the subject belongs.

Does performance level affect speed?

To continue adding elements to confirm the stability of the speed with each percentage, it could be assessed whether the speed with each percentage is similar or not between people with different levels of performance.

From the results of the study it can be deduced that, indeed, the speed with each percentage is very similar between people with a very different level of performance. By dividing the group of 176 cases into four groups based on their relative MR (RM * body weight-1), the mean speeds from 30 to 95% of the RM were 0.76, 0.77, 0.77 and 0.73 m*s- 1 (table 4), in this order, from the group with the lowest performance to the most expert group, respectively.

Therefore, the average speed is almost the same despite the performance increase considerably. Consider that the subjects with the lowest performance did not get to lift a weight equivalent to their own body weight in the bench press, while some of the most expert subjects came to lift twice their body weight or approached this mark.

Less performing subjects failed to bench press their own body weight, while some of the most experienced subjects lifted twice their body weight

Only the highly expert group, the one with the highest performance, experienced a minimal statistically significant average reduction in speed with each percentage compared to the others. However, a tendency to decrease speed is not even observed as performance increases, since the second group with the lowest average speed is that of the less expert subjects (0.76 m*s-1).

In addition, the statistical differences in this case are not relevant in practice, since the absolute difference between the most expert group and the least experienced group is not even 0.03 m*s-1 (specifically, 0.027 m*s- 1), which would be equivalent to a -1.69% difference in the RM percentages between the two for the same speed.

Tabla 4. Relative strength (relative strength), mean speed with percentages from 30 to 95% of the RM (mean test velocity) and speed with the RM (V1RM) of four groups of cases (subgroup) formed according to their performance.

However, if these results are analyzed in greater depth, it is concluded that these differences are not real. Responding to the question formulated in the lower part of Table 4, the apparent lower speed with each percentage of the most expert group is due to the fact that the average speed with which the components of this group reach their RM is slightly less than that of the others (0.045 m*s-1 with respect to the group with the lowest performance, and 0.019 and 0.014 m*s-1 for the other two groups).

This fact causes that, necessarily, the speed with each percentage tends to be lower, which comes to ratify, once again, what has already been revealed previously. Thus, the slight decrease in speed with each percentage of the top performing group in the bench press exercise is due to the tendency to decrease speed with RM in extremely expert subjects.

It is reasonable to accept that these subjects are able to make the most of their own strength potential, because they have more confidence in their possibilities and better technique when executing the exercise. It should be noted that, given the characteristics of the subjects in this study, the generalization of these data leads us to be able to apply them to the entire population, since in the group there are subjects who lift from less than 90% of their body weight up to subjects lifting twice their body weight.

This means that any young person practicing any sport or simply using strength training can be included here. Therefore, this is one of the few exercises that would really allow us to assess our strength-speed “profile”.

If we execute the exercise well, we will be able to know to what extent our performance in this exercise is in the average of the population in terms of speed with each percentage, if it is slightly above or if it is slightly below, or even if it is below. above or below in some areas and not in others of the force-velocity curve or not.

However, to make these assessments, one must also take into account the speed at which MR is reached. But the stability in the relationship between the percentages of the RM and their corresponding speeds also occurs in any exercise in which the measurements have been made well.

Table 5 shows the data corresponding to the complete squat exercise. The group consisted of 80 subjects. The differences in performance are important, from 93 to 126 kg on average, with coefficients of variation from 12 to 18%, and some subjects lifting more than twice their body weight (1.57 to 2.17 range in the highest performing group).

Therefore, we can admit that it is a sample that includes a range of performance in which a wide population of athletes can be found.

the average speed of all the percentages is practically the same

However, the mean speed of the set of percentages (mean test velocity) is practically the same (0.873, 0.867 and 0.865 m*s-1) The speeds with the percentage examples included in the table are practically the same in the three groups , existing between 0.01 and 0.02 m*s-1 as a maximum difference. The MRI speed of each group is practically the same as that of the others, and the same as that indicated in the year 2000 (González-Badillo, 2000). No significant difference is observed in any of these speed values.

Tabla 5. Comparison of the mean speeds of the tests with percentages from 30 to 95% of RM (mean test velocity), mean propulsive velocity with different percentages (MPV), mean propulsive velocity with RM (MPV with 1RM) in three groups formed based on their vative performance with respect to body weight (RSR) in the full squat test. The effect size is represented by the “eta” statistic (effect size n2) (Sánchez-Medina et al., 2017).

Therefore, In an exercise as different from the bench press as the squat, the stability of the speed is confirmed with each percentage, although the performance of the subjects is very different. It has been indicated that the speed with each percentage is dependent on the speed with which RM is reached. This tendency has been verified when analyzing the different examples of performance with the bench press exercise.

Although this tendency not only occurs in the same exercise when the speed of the RM changes due to its faulty measurement, but naturally also occurs between the different exercises, because each exercise has its own speed, and different from that of the others. , from his RM (González-Badillo, 2000).

In this article, published with data recorded in the 1990s, it was already commented that the speed with 40% of the RM of the bench press was 1.15 m*s-1, which differs in only two hundredths of a m*s-1 of the current data (1.13 m*s-1), and the squat had a speed of 0.93 m*s-1′ with 64.3% of the RM, practically the same speed that is currently proposed (0.92 m*s-1 with 95%. see table 6).

each exercise has its own speed, and different from the others

Likewise, it was confirmed that the speed with each percentage depended on the speed of the RM, because the snatch, with an average RM speed of 1.04, the speed of 1.15 m*s-1 was obtained with 91% of the RM, while, as we have indicated, this same speed of 1.15 m*s-1 with the bench press belonged to 40% of the RM, with a speed of his RM of 0.2 m* s-1. The same was the case with the power clean: 1.09 m*s-1 for 87% of the RM and a velocity of his RM of 0.9 m*s-1.

The fact that the speed with each percentage depends on the speed of the RM is so evident that we can say that it is “truth”, although this does not prevent someone from occasionally questioning it.

It is evident that if the speed of the RM of an exercise is, for example, 0.2 m*s-1, the speed of 95% of the RM of that exercise should be approximately 0.26-0.28 m *s-1, and 90% should be 0.32-0.34 m*s-1 and so on, but if the RM speed of the exercise is 1 m*s-1, 95% of the MRI will have to be a few hundredths of a meter per second faster, for example, 1.08-09 m*s-1, more or less, but always very far from 0.26-0.28 m*s- 1 of the exercise whose MRI velocity was 0.2 m*s-1.

Naturally, this is confirmed when the speeds of different well-measured exercises are compared with different speeds of their own RMs.

Table 6 shows the speed data with each percentage corresponding to four very common exercises in strength training (bench press: González-Badillo and Sánchez-Medina, 2010; pull-ups: Sánchez-Moreno et al., 2017; squat : Sánchez-Medina et al., 2017; rowing table: Sánchez-Medina et al., 2014).

Tabla 15.6. Speed ​​with each percentage in the bench press, pull-ups, squats and plank rows.

Table 6 shows that the speed values ​​of each percentage increase as the speeds of the RMs increase. The relationship between the speeds of the RMs and the average speed of all the percentages from 65% to 100% is almost perfect (r= 0.97; p < 0.05).

It is very relevant that with only 4 pairs of data the correlation is statistically significant. Therefore, it is confirmed that, indeed, the speed with each percentage is dependent on the speed of the RM of the exercise, as well as the differences in the speed of measurement of the RM when it is measured more than once within each exercise. .

As a synthesis of all the above, it is confirmed that training can be controlled through the speed of the first repetition in the series, provided that it is done at the maximum speed possible, and this is based on the fact that we can start from the assumption that if Although the value of 1RM can change between different days, the speed at which each percentage of the RM is performed is very stable.

It is confirmed that the training can be controlled through the speed of the first repetition in the series as long as it is done at the maximum possible speed.

Therefore, speed control can inform us with high precision about what real percentage or what effort is being made at each moment. Therefore the own speed of each percentage of 1RM determines the real effort. This means that the speed of the first repetition of a set determines the degree of effort that the load represents.

Thus, the training load (mass) can be determined by the speed of the first repetition. If this is so, what should be programmed is not the percentage of 1RM or an XRM, but the speed of execution of the first repetition of the series. Note: for convenience or to be more intuitive, it could be programmed by means of the RM percentages, but the absolute loads (masses) that correspond to those of the percentages would always be determined through the speed of the first repetition of the RM. series, not by the result of the arithmetic calculation of the percentage.

conclusions

From all of the above, it can be deduced that using the speed of execution as a reference to dose and control the training far exceeds what the percentage of 1Rm and XRM contributes. Therefore, the existence of a high stable relationship between speed and the different percentages of 1RM allows a series of applications such as those indicated below.

All the data that have been provided have been obtained and are applicable to men. For women, the corresponding speed values ​​have not yet been published, but laboratory data, in the publication phase, indicate that the speeds with each percentage are practically the same with women from a relative intensity of 45-50%, reducing approximately at 0.03, 0.04 and 0.06 m*s-1 with the intensities of 40, 35 and 30% of the MR, respectively.

the speeds with each percentage are practically the same with women

Knowing the speed of the first repetition (speed with each percentage) allows:

• Evaluate the strength of a subject without the need to perform a 1RM test or an XRM or nRM test at any time.
• Determine with high precision what real percentage the subject is using as soon as he performs, at the maximum speed possible, the first repetition with a determined absolute load.
• Estimate / measure the improvement or not in performance EVERY DAY without the need to perform any test, simply by measuring the speed with which an absolute load moves. If, for example, the difference in speed between 70 and 75% of the RM of a specific exercise is 0.08 m*s-1, when the subject increases the speed by 0.08m*s-1, with the same load absolute, there is a very high probability, almost 100% that the load with which you train represents 5% less intensity. Naturally, if what is produced is a loss of speed before the same absolute load (kg), we can be quite sure that the subject is below his previous performance, and in a proportion proportional to the loss of speed before the same load. absolute load.
• The measurement of the speed of the first repetition on a daily basis, just week before and after the training allows:
  • Know the degree and time of adaptation individually.
  • Discover the degree of disparity of the adaptive responses.
  • Check the effect of improving strength on other types of performance trained or not.

Regarding the speed of the MRI, it can be concluded that:

• The only way to be able to consider an MR as “true” or false is to measure the speed with which it is achieved.
• Two MR values ​​of the same subject cannot be compared if the values ​​of the speeds with which they have been measured are not the same or very similar.
• If the speeds at which the pre-post training RMs have been measured are different, with differences greater than or equal to 0.03 m*s-1, these RMs are not equivalent, so comparing the values ​​of the RMs (weights raised) pre-post training would lead to erroneous decisions, considering that there have been some changes in strength (in the MRI) that are not real.
• In addition, the speeds with each percentage would appear to be different, without meaning that they really are.

Regarding the assessment of the effect of training, it is concluded that:

• MRI is not necessary and should never be measured.
• The best procedure for assessing the training effect is to re-measure the speed reached at the same absolute loads that were measured in the initial test.
• This procedure is the most coherent and precise, since the effect of strength training is measured by the change in speed at the same absolute load or, as already indicated, the assessment of the training effect through changes in MR. , even in the not very probable assumption that the speeds with which the RMs are measured are the same or very similar, it would only inform us about the effect of the training before the maximum load (RM), but not before other lower loads

Other apps:

• Use strength training with all subjects, from children to the most advanced athletes or adults and older people who want to improve their health, without the need to do maximum effort tests (1RM, or XRM, for example) in any case.

The authors’ proposal, therefore, is that the mean propulsive velocity of the first repetition should always be used to program, dose and evaluate the training load and the performance of the subject.

The density is expressed by the relationship between the total work or the number of repetitions performed and the time spent on it. In this sense, it is identified with a way of expressing the overall mechanical power of a training unit. Density is primarily determined by the recovery time between reps and sets, although it also extends to recovery between sessions and between full training cycles.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

Summary

• Training density is the relationship between the volume of training and the time spent doing it.
• A higher density tends to produce greater metabolic stress and greater fatigue.
• High intensities and densities of training, which are probably only necessary —if they are at all— for advanced athletes, have a limit from which their use can be negative.

The recovery time comes to complete the characteristics of the intensity of the training. Thus, given the same intensity and volume, the greater the density of the training carried out, the greater the overall mechanical power and, therefore, the greater the overall intensity of the training. The effects and importance of recovery go beyond the training session to influence the entire cycle, the relationship between cycles within a season and even between seasons.

The density is expressed by the relationship between the total work or the number of repetitions performed and the time spent on it.

On many occasions, the best solution to achieve a clear improvement in performance, whether there has been a phase of overtraining (stagnation or setback in results) or not, is a long recovery period without training, rest (González- Badillo, 1991, p.100).

The higher or lower density within an exercise or session can influence the training effect, since a lower recovery between series, that is, a higher density, tends to produce greater metabolic stress and greater fatigue., which must be taken into account as a determining factor of the overall load used and the effect expected from the training. Therefore, the training density can be considered as a complement to the other intensity criteria, but, although it is generally subordinated to the objectives defined by the other criteria, it must be taken into account as a possible determining element of the load magnitude. .

As occurs with the training volume as a component of the load, studies have also been carried out on intensity aimed at determining the degree of intensity or load and physical and sports performance. Making a synthesis of a good part of them, we highlight some data below.

The problem of optimal load and stimulus effectiveness within the training process is not satisfactorily resolved (Pampus et al., 1990). The importance of the optimal training load is justified by the small differences in performance between winners and losers in a competition (Kuipers, 1998), although there is very little scientific data on optimal training to reach maximum performance (Kuipers, 1998). , nineteen ninety six).

The importance of the optimal training load is justified by the small differences in performance between winners and losers in a competition.

While the rapid or immediate improvement in performance may be directly related to intensity, the final level of performance is inversely related to training intensity (Edington and Edgerton, 1976; in Stone et al. 1991). In this sense, it has been verified that if an athlete tends to perform the greatest possible number of repetitions with intensities greater than 90% of his RM, he does not achieve the best results (González-Badillo et al. 2006), as well as that the number of repetitions with intensities greater than 90% of the RM does not have a positive linear relationship with the results (González-Badillo et al. 2006).

The explanation for this lack of linearity when maximum achievable values ​​of maximum intensities are reached could lie in the lack of positive response of the organism to an excess of stimulation and a high training density. This has been concluded in some studies.

For example, it is stated that the coincidence of very high values ​​of volume at the moment in which a high intensity is also performed is very likely to lead to overtraining (Kraemer et al. 1995), or that using 70 repetitions per week with intensities 100% of 1RM led to overtraining (decreased squat result), while performing 40 repetitions per week with intensities close to maximum (95%) produced improvements in 1RM (Fry et al, 1994).

It has been proven that if an athlete tends to perform as many repetitions as possible with intensities greater than 90% of his RM, he does not achieve the best results.

From the study by Medvedev and Dvorkin (1987) it can be deduced that the optimum percentage of 1RM for strength improvement is not the same for all ages and performance levels. Indeed, in this study it was observed that the youngest subjects, 13-14 years old and 15-16 years old, improved more with mean percentages of 70 and 80%, respectively, with those who did 3-4 repetitions per series, which using 90% percentages with 1-2 repetitions per set.

It therefore seems reasonable that we should get the most out of each range of percentages before using the highest percentages. Even in the older group of athletes (17-20 years) in this same study, 80% produced in the long run (at the end of the 6 and 8 months that the study lasted) better effects than 90%.

These results seem to justify Edington and Edgerton’s (1976; in Stone et al. 1991) suggestion noted above that while rapid/immediate performance improvement may be directly related to intensity, the final level of performance is inversely related to training intensity (and in turn the training density), and also with the conclusions of Fry (1998), which indicates that the use of maximum intensities (1RM) can be satisfactory in a short space of time, but the continued use of these training units will frequently be negative to continue improving, y Fry et al. (2000), when they conclude that even in the event that the continued use of this work system does not produce a decrease in the result in the trained exercise (squat), it can be counterproductive in other performances such as speed (Fry et al. ., 2000).

the use of maximum intensities (1RM) can be satisfactory in a short space of time, but the continued use of these training units will frequently be negative to continue improving

Therefore, if a high intensity is maintained for a long time (90% for 6-8 months, in the study by Medvedev and Dvorkin, 1987), the results tend to decrease, and may even lead to overtraining, or, at best, cases, the results would be lower than those obtained with medium intensities.

These results are in the same line as those obtained by González-Badillo (González-Badillo et al., 2006), in which it was observed that the relationship between the number of maximum repetitions (90% and more of the RM) and the results is curvilinear, or with the results of Busso (2003), who finds a curvilinear relationship between the daily training load and the gain in performance.

This suggests that these high training intensities and densities, which are probably only necessary —if at all— for advanced athletes, have a limit beyond which their use can be negative.

In addition, this limit is not determined by the athlete’s own ability to carry out training sessions with these intensities, since those subjects who performed the greatest possible number of repetitions with more than 90% did not achieve the best, observing that these intensities did not have a positive linear relationship with the improvement of the marks (González-Badillo et al., 2006).

Fatigue is a complex and multifactorial process that affects performance. Neither the way fatigue occurs nor the hierarchy of factors that cause it in any of the production modalities is still not completely known.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

Summary

• Fatigue can be defined as any situation in which the value of muscle activation is inevitably and involuntarily decreased.
• The feeling of fatigue increases faster than the amount of work done in the unit of time to protect the body from possible injury.
• Without fatigue there would be no possibility of improving performance, because the adaptation processes would not take place. The challenge is to reach the degree of fatigue with which to obtain the best results.

Observations related to fatigue range from the will to perform specific acts to changes in the behavior of intracellular proteins. In general, it could be conceptualized as the inability to continue a task at a stipulated level (usually stipulated by the central nervous system).

The difficulty in understanding the production of fatigue derives from numerous factors: places where it can originate, the different methods that must be used to measure the effects of fatigue, the difficulty in extrapolating in vitro results to situations in normal or physiological conditions or difficulty in integrating all the results.

The feeling of fatigue increases faster than the amount of work done in the unit of time (Mosso, 1904), thus protecting our body from possible injuries of lesser or greater severity.

Thus, fatigue is largely an emotion, part of a complex regulatory system that keeps us from taking risks. In extreme conditions, in which the will ignores this emotional indicator, tissue damage occurs and, in very extreme cases, death.

We have examples of this every day in endurance competitions such as the marathon, which precisely commemorates the death of a soldier (Philipides) who, ignoring his fatigue, insisted on continuing to run until he exceeded the limits of the regulation systems and died after deliver important news.

The feeling of fatigue increases faster than the amount of work done in the unit of time

Our brain uses fatigue symptoms as a key regulator to ensure that exercise is stopped before bodily harm is done. However, among the symptoms of fatigue, the “sense of effort” stands out.

This feeling of exertion increases as more repetitions of a task are performed, until just one more repetition is an extreme effort. This sensation of effort is proportional to the difference between the task commanded by the nervous system and the real difficulty in carrying it out.

For its part, the difficulty in carrying out a task will depend on many mechanical, physiological and biochemical variables at different levels from muscle cells to the organs in charge of general homeostasis. This sensation of effort is modulated to a certain degree by the will of the athlete.

For individuals with the same level of training and performance, the differences between winners and losers sometimes only includes the mental decision, the will, different in the winners.

Fatigue is synonymous with a wide range of physiological conditions, from pathology and general health to sport and exercise (Wilkinson et. al., 2010). Fatigue in sport and physical activity in humans has usually been described in subjective terms and has been measured by the acute reduction in physical performance during and after exertion.

The consequence of exercise-induced fatigue is the inability to maintain a certain value of applied force, which results in loss of speed and power of execution in dynamic actions. It is considered that there are three factors through which fatigue is expressed in mammalian muscle:

1) reduction in the number of active cross bridges, which affects the loss of isometric strength,

2) reduction of the maximum speed of muscular shortening in activations without opposition to the shortening (absolute speed) and,

3) increase in the curvature of the force-velocity curve that affects the reduction of maximum power (Jones, 2019).

For individuals with the same level of training and performance, the differences between winners and losers sometimes only includes the mental decision, the will, different in the winners.

Therefore, fatigue is quantified by the loss of strength, muscle shortening velocity, and force production in unit time (RFD). Loss of static or isometric strength depends on reducing the number of active cross bridges (pc) and the force exerted by each pc.

The loss of speed and RFD depends on the decrease in the rate of formation and activation of pc. As a consequence of the loss of strength and speed, power will decrease. A phenomenon associated with the above that affects them is the deactivation rate of the pc, which is a determining factor in the relaxation time and in the rate of formation of the pc themselves.

However, the physiological mechanisms prior to the final consequences that we have just indicated, and that underlie fatigue, give rise to different proposals and are still the objective of numerous investigations.

The causes of fatigue may be related both to the oxygen transport capacity and the available metabolic substrates, as well as to the cerebral causes of the contractile fibers of skeletal muscle and the muscle activation mechanisms themselves. Therefore, the decrease in force / speed associated with fatigue can originate in any process at different levels, from the brain order to the formation of actin-myosin cross-bridges (Debold, 2012).

But in practice, to study fatigue it is necessary to specify the task and the production mechanism. Otherwise it would be, if not impossible, if not very complex, to study all the elements that can intervene in the generation of fatigue simultaneously. For example, the speed and extent with which fatigue occurs depends largely on the type and intensity of the physical activity performed (Fitts, 1994).

But the main purpose is not to discuss the different opinions regarding the causes of fatigue or the methodologies used to detect and measure them, but to expose the most accepted ideas, although also discussed, and that have a practical application for physical and sports performance. .

fatigue concept

Fatigue can be defined as any situation in which the value of muscle activation is inevitably and involuntarily decreased. (loss of force, production of force in the unit of time or RFD, speed, power,) with respect to another value reached in a time immediately prior to the effort. In this sense, Macintosh and Rassier (2002) define it as a contractile response that is less than what is expected for a given stimulation. It can also be expressed as the inability to maintain a certain intensity (speed or power) over time.

And it can also be defined and differentiated by the recovery time after the effort. Fatigue can begin in the first moments after the muscle activation command is initiated or from the first effort in a series of repeated efforts, without the need for muscle failure or the inability to maintain a certain intensity.

Therefore, the most relevant and appropriate way to define fatigue is to consider it as the magnitude and time of loss of performance in whatever the situation may be in relation to what is programmed or intended by the will or the CNS. From these definitions the need to know the value of contraction or performance prior to the measurement of fatigue can be deduced. Therefore, the conditions that must be met for us to be in a position to quantify fatigue are that there is loss of performance, that this loss does not occur voluntarily, and that there is a previous value that is taken as a reference.

In the Essential Dictionary of Sciences, fatigue is defined as the deterioration of the performance of a living being… over time. It is associated with a feeling of tiredness, lack of concentration, slowness and the appearance of simple errors. But a muscular activation, in addition to fatigue, can also produce potentiation, which is an opposite response to fatigue, whereby an increase in muscular performance is produced as a consequence of an immediately previous activation. Therefore, fatigue and potentiation can coexist.

The possible existence of two opposite effects in the same muscle activation makes it difficult to determine the degree of fatigue. In this situation, great care must be taken in the interpretation of the data referring to a “before” and an “after”: the result can be a mixture of fatigue and potentiation.

However, potentiation has a limited duration while fatigue may persist until functional incapacity. Even when the post-effort performance is greater than the initial response, there is no guarantee that the mechanisms associated with fatigue are not present (Macintosh and Rassier, 2002).

a muscular activation, in addition to fatigue, can also produce potentiation, which is an opposite response to fatigue, whereby an increase in muscular performance is produced as a consequence of an immediately previous activation.

In this way, we can find situations in which the response is greater than that which occurs in the resting state (potentiation), but probably less than what could be expected if there were no fatigue. In fact, In training practice, it is observed that when the efforts are not made until exhaustion, the response after the effort (for example, measured through the vertical jump) in some cases is superior to that offered before it., even having previously warmed up to reach maximum initial performance.

That is, the effort has meant a “better warm-up” than the one previously made. But there are also situations in which the contractile response is less than before the effort. If this is the case, it can be concluded that fatigue exists with certainty, but its quantification is not easy, because there are also potentiation mechanisms simultaneously. This means that if the potentiation mechanisms were not present, the magnitude of the fatigue measured would be greater.

The term fatigue should not be identified with situations in which one becomes exhausted, with a forced interruption of the activity. Muscle fatigue begins immediately after starting physical activity and includes changes in physiological processes that reduce muscle strength (Enoka, 2002).

fatigue and training

Fatigue must be considered as a component of training, and therefore, it must also be considered as an essential character of the stimulus necessary to ignite the adaptation processes of training. The degree of fatigue (subjective, observed by the coach, or measured through the relevant means) is the reference point to determine and assess the training load. Without fatigue there would be no possibility of improving performance, because the adaptation processes would not take place. The problem that arises is the degree of allowable fatigue to achieve the best result, or how training makes us more resistant to fatigue.

Without fatigue there would be no possibility of improving performance, because the adaptation processes would not take place. The problem that arises is the degree of fatigue that is acceptable to achieve the best result, or how training makes us more resistant to fatigue.

degree of fatigue

Overload is a situation in which the subject is subjected to a stimulus (load) higher than usual. In order to produce fatigue, it is not necessary for overload in this sense, but other minor stimuli than the usual ones can also cause fatigue. Depending on this degree of fatigue and its duration, we find ourselves in three different situations:

i) acute or immediate fatigue of short duration (from a few minutes to a few hours or 2-3 days)

ii) fatigue of medium duration (from several days to 2-3 weeks) and,

iii) long-term (chronic) fatigue (several weeks to several months)

Acute fatigue corresponds to the fatigue produced by an exercise (a series or repetition) or a training session. Recovery should occur before the next set or repetition (in full or in part) or before the next session (in full).

Medium duration fatigue is the fatigue produced intentionally by several training sessions. It is made up of several units of acute fatigue without sufficient recovery between sessions. After several training units, a special, broader recovery occurs. It is expected that from this sustained load phase a higher supercompensation phase will emerge, which corresponds to the English term “overreaching”, for which there is no equivalent term in Spanish. but if the consequence is that optimal supercompensation is not reached, the subject is considered to be in an “overloaded” situation, or with excessive fatigue.

Chronic or long-term fatigue does not occur on purpose. It is the consequence of an error in training programming, although it can sometimes be associated with other circumstances such as certain diseases. It is caused by carrying out an excessive number of fatigue phases of medium duration. Sometimes it is difficult to distinguish between the phase of medium and long duration fatigue. Recovery from this state of fatigue may take several months. It corresponds to the English term “overtraining”, which in Spanish would be equivalent to the term “sobretraining”.

The following article analyzes several studies carried out to analyze acute fatigue in different types of efforts and its relationship with the loss of execution speed.

In this series of articles we deal with some of the most important concepts of strength training, collecting notes from the recently published book Strength, Speed ​​and Physical and Sports Performance written by renowned researchers Juan José González Badillo and Juan Ribas Serna.

SUMMARY

• Fatigue directly depends on the loss of speed in the series, regardless of the number of repetitions that can be done with the load being trained.
• The measurement of fatigue after an effort to exhaustion when moving loads should be done especially through speed and RFD (force production per unit of time).

In a study carried out by Sánchez-Medina and González-Badillo in 2011, the loss of speed in the series (at the end of three sets with the same absolute load) by performing at the maximum speed possible 15 different types of effort with the bench press and squat exercises. These efforts are expressed in terms of Character Effort (EC), such as: 3×6(12), where the first number expresses the number of sets, the second the number of repetitions performed, and the number in parentheses the number of possible repetitions in the set.

The efforts were as follows: 3×6(12), 3×8(12), 3×10(12), 3×12(12), 3×6(10), 3×8(10), 3×10(10), 3×4(8), 3×6(8), 3×8(8), x3(6), 3×4(6), 3×6(6), 3×2(4), 3×4(4). The approximate percentages of 1RM that these loads represent are the following: 70% for 12 possible repetitions, 75% for 10, 80% for 8, 85% for 6 and 90% for 4, although the subjects made the efforts with the absolute loads that could move the maximum repetitions under analysis at the maximum possible speed: 12, 10, 8, 6 and 4, not the percentages that represent this number of reps. requests.

En la figura 1 se puede observar un ejemplo de uno de los esfuerzos [3×12(12)].

Figure 1. Example of speed evolution when three sets of 12 repetitions are performed with a load with which only 12 repetitions can be done. The loss of speed (fatigue) can be observed within each series and in the total of the series. Fatigue is estimated by the loss of speed with the load that could be moved at 1 m*s-1 (average 1.03 m*s-1 in three repetitions) before the first series. The loss of speed reached 31.1% (average speed 0.71 m*s-1) after the last repetition of the last series. (Sánchez-Medina and González-Badillo, 2011).

Figures 1 and 2 show the relationship between the loss of speed in the line and the loss of speed with the load that had moved 1 m*s-1 before carrying out each one of the efforts. The high relationship between the compared variables indicates that the loss of speed in the series, at least between 70% and 90% of 1RM, is an accurate estimator of the degree of fatigue generated by training in both exercises.

acute fatigue depends directly on the loss of speed in the series, regardless of the number of repetitions that can be done with the load that is trained

In addition, it can be stated that fatigue directly depends on the loss of speed in the series, regardless of the number of repetitions that can be done with the load being trained. This affirmation is based on the fact that for intervals of 5-7% of losses in the series (axis X) occur with similar losses of speed with the load of 1 m*s-1 belonging to the different types of effort (axis Y). Result. two similar ones were obtained when the relationship between the speed losses in the series and the height loss in the vertical jump was calculated (figure 2).

Figure 2. Correlation between the loss of mean propulsive velocity (VMP) in the series and the loss of VMP with the load of 1 m*s-1 in the bench press exercise. Each color represents the CE with a different maximum number of repetitions/series (blue: 12 possible repetitions; yellow: 10; green: 8; pink: 6; red: 4) (Sánchez-Medina and González-Badillo, 2011).

The results of this study indicate that regardless of the cause, within the intensity ranges studied, the fatigue caused by a training session with loads depends on the percentage of speed loss in the series (at the end of the three series, in this case), regardless of the number of repetitions that can be performed in the series itself.

This conclusion is justified by the close relationship between the speed losses in the series and the speed loss with the load of 1 m*s-1 and the height loss in the vertical jump. In turn, the loss of speed with the load of 1 m*s-1 and the loss of height in the vertical jump are precise estimators of the metabolic stress caused by the training session, naturally due to the high relationship of these variables with the concentration of lactate and ammonium.

It is also noteworthy that, if we take the ammonium concentration as a reference, when the speed losses in the series (the three series) do not exceed 30% in the squat or 40% in the bench press, it seems that the emergency pathway of energy production is set in motion, so fatigue does not seem to be excessive in these cases.

Therefore, speed control not only allows estimating the degree of fatigue, but in this case it informs us about the possible consequences if certain physiological stress barriers are overcome. The causes of loss of speed within the series and the loss of speed cal the load of 1 m*s-1 and the vertical jump can be associated with those that we have indicated for the efforts of short duration.

Therefore, the results of this study lead to reflection and conclusion that it cannot be affirmed that the greater the absolute intensity at which an activity is carried out until exhaustion, the greater the fatigue.

It can be affirmed that the time or the number of repetitions that this intensity can be supported will be less. In other words, muscular failure, exhaustion, is reached sooner, and therefore fatigue develops more quickly the higher the intensity, but the fatigue does not have to be greater, rather it will actually tend to be less.

In this case, it is observed that fewer repetitions per series can be done the higher the load or intensity (1RM percentage), and therefore muscle failure and exhaustion are reached earlier, but fatigue is less: less speed loss in the series and with the load of 1 m*s-1 and less height loss in the post-effort vertical jump.

From this conclusion it should not be deduced that training with external loads should be done with the highest intensities, because this would generate less fatigue. Other factors such as the absolute speed of execution, maximum and average, the nature of the effort and the number of total repetitions to be performed are determining factors in the training effect.

Fatigue in a dynamic effort with loads to exhaustion

In the laboratory, the authors carried out a study in which they tried to verify the degree of fatigue and the post-effort recovery time of a dynamic exercise, measured through the changes in force, speed and RFD (rate of force development or force per unit of time) in a static and a dynamic test (Rodríguez-Rosell, Doctoral Thesis).

To do this, 28 physically active subjects, with experience in strength training, performed a test to muscular failure in the bench press exercise with a load that they were capable of moving at a speed of -0.78 m/s (-60% of 1RM). Before, immediately after, and at 3, 5, 10, 15, and 20 min after finishing the effort, an isometric and a dynamic measurement were made.

The degree of fatigue and recovery in the dynamic measurement was determined by the performance with the load that could be moved at 1 m*s-1, which was measured before the effort and in the six moments after the effort. In the dynamic measurement, the variables analyzed, among others, were the Mean Propulsive Velocity (MPV), Peak Force (PF), Peak Velocity (PV), and Maximum Force Production in Unit Time (MRFD), The first observation is that the loss of the values ​​of these variables is not linear through the total number of repetitions performed until exhaustion.

When comparing the loss during the first and second half of the total number of repetitions performed, it was observed that the losses in the second half were significantly higher than in the first half in all variables. The VMP (43%) and the PV (43.5%) were the variables that lost the most in the second half with respect to the first, followed by the MRFD (38.6%) and, to a lesser extent, the PF (12%).

Immediately after the effort, the yield loss percentages were 58.4 in the VMP, 59.3 in the PV, 65.8 in the MRFD and 28.9 in the PF. At 20 minutes after the effort (last post-exercise test), none of the variables had recovered in a statistically significant way, although with a greater recovery ra of the PF variable with respect to the other three.

The values ​​of these variables at the end of 20 minutes of recovery with respect to the initial test were 89.1 (VMP), 86.8 (PV), 83.9 (MRFD) and 94.6% (PF).

Furthermore, the RED values ​​at times 0-50, 0-75 and 0-100 ms also did not recover significantly at the end of 20 min. From these results it can be deduced that speed and force production in unit time are much more sensitive to fatigue than the applied peak force.

Therefore, the measurement of fatigue after an effort to exhaustion when moving loads should be done especially through speed and RFD, since if only the peak force is measured, the information may be erroneous.

Given the difficulty of measuring RFD in most cases, speed once again appears as the best way to control the degree of fatigue and recovery after exertion.

In the static or isometric measurement, the MRFD was at 77.8% of the initial value] at 20 minutes of recovery, while the PF was at 96.3% of the initial value. In the test immediately after the effort, the MRFD lost 66.6% and the PF 29.9%.

As in the assessment of fatigue through dynamic measurement, in static action the MRFD is much more sensitive to fatigue than the peak force. The PF value was no longer significantly different from the initial test at 20 minutes, while the MRFD was.

Therefore, in static actions, fatigue can also be assessed more precisely through the production of force in the unit of time than by the peak force reached. It can be seen that the yield loss and recovery values ​​were similar when evaluating them through dynamic and static action.

Similar results were found by Buckthorpe et al., (2014), who, after carrying out repeated efforts in an explosive manner, verified that the RFD declined faster and more pronouncedly than the maximum force. The initial phase of the RFD (0-50 ms) was especially sensitive to fatigue. According to these authors, both neural (central fatigue) and contractile (peripheral fatigue) mechanisms seem to contribute to the reduction of RFD and maximum force.