This article analyzes why free weight exercises are preferred over machine exercises for efficient strength development.

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

• Work with free weights consists of performing exercises with external loads that move freely, depending on the magnitude and direction of the forces exerted by the subject.
• The advantages of free weight exercises over machine exercises are that they can be performed in all planes and in multiple directions, allowing multiple muscle groups and connective tissue to work to control the range of motion.
• The improvement of the strength in isolation of the muscles (training with machines) that intervene in a specific specific action can have a negative effect on the result of the training.
• Localized training of the extensor muscles of the lower back (training with machines) can have a positive effect on specific performance.

With the exception of a few exercises, such as, for example, exercises for training the adductors and hamstrings and some more, the complementary exercises that an athlete uses to improve specific performance should preferably be performed on machines, that is, with free weights.

The exercises that an athlete uses to improve specific performance should preferably be performed without machines

El trabajo con pesos libres consiste en realizar ejercicios con cargas externas que se mueven libremente, según la magnitud y la dirección e las fuerzas ejercidas por el sujeto. Within these exercises, a clear distinction must be made between the so-called “Olympic” ones: which are the snatch and two times and the partials of these, such as the power snatch, power clean… and the rest.

The advantages of free weight exercises over machine exercises are that they can be performed in all planes and in multiple directions, which can encourage numerous muscle groups (agonists, antagonists, stabilizers, and synergists) and connective tissue to act to control the movement path. This can create considerable kinesthetic information, which has a positive effect on balance, coordination, control of accelerations and decelerations in the various phases of the movement path, and the strengthening of muscles and connective tissues (1988 (Walsh, 1989; Armstrong, 1992 and 1993; Field, 1988).

In summary, in the opinion of Field (1988), work with free weights is the most effective means of training with loads for the development of speed, power and acceleration (although it would be more appropriate to say: “…it is the means of training with loads more effective for the development of force”)

As Kraemer & Nindl (1998) propose, when a machine sets the pattern of movement in an exercise, it also sets the tissue that will be recruited. This way of fixing the movement leads to an isolated muscle training, in such a way that the risk of producing a muscular imbalance is more likely than if exercises with free weight are used. A lack of variation in the recruitment pattern of muscle fibers, a lack of demand to maintain balance in different planes of movement and a lower use of synergistic muscles during the execution of exercises with machines can reduce the specificity of the exercise to apply its benefits. competition effects.

Free weight work is the most effective means of training for strength development.

In relation to the global training load, it must be taken into account that the demand of free weights seems to be greater than if the same training (intensity and volume) is done with machines. This may be due to an increase in the physiological requirements to control the exercises when they are done with free weights (Fry et al., 2000). This conclusion is reached after observing that training with free weights and high-intensity loads produces more setbacks or stagnation than higher-intensity training done with machines.

If you want to “tune” a lot in the training dosage, this may be important for programming the magnitude of the load, since the data suggest that the ability of an athlete to support loads with high intensity with free weights is lower than if the same loads are done with machines.

It has also been proposed that free weight exercises are much more effective in preventing injury and helping to improve performance than calisthenics or machine exercises (Parker, 1992). A problem associated with exercises performed on machines is the high probability that isolated or mono-articular muscles are trained, without significant intervention from other muscle groups and joints in a coordinated manner.

This circumstance means that the application or transfer of the improvement of muscular strength to competition gestures is scarce or null in most cases. For example, Baratta et al. (1988) found that specific training of the knee flexors results in increased activation of these muscles when trying to extend the knees.

Therefore, the training of isolated muscles can interfere with performance, which always requires the coordinated participation of antagonist, agonist, and synergist muscles. Something similar was observed by Bobbert and Van Soest (1994), who, when training the strength of the muscles involved in the vertical jump in isolation, the height of the jump was reduced by 9 cm, although the knee extensors improved their strength by 20%. .

the data suggest that the ability of an athlete to support loads with high intensity with exercises with free weight is lower than if the same loads are done with machines.

Therefore, it seems that the improvement of the strength in isolation of the muscles involved in a specific specific action can have a negative effect on the result. The explanation for these behaviors may lie in the fact that muscle groups work simultaneously when performance is sought in competition or in a multi-joint exercise, not by separate muscle groups.

Therefore, the imitations of these exercises are given by the fact that they do not train movements, but muscles. A seated knee extension is a muscle training (quadriceps), while a full squat would be the training of a movement, in which a series of muscle groups is used —and trained at the same time—, but whose fundamental objective is the improvement of the movement itself —because of the importance that this may have for sports performance—, not of the muscles involved in it.

Therefore, localized or isolated muscle group exercises have, fundamentally, a complementary auxiliary role or support for those exercises/movements that are the most determinant for improving specific performance. They may also have the function of preventing and recovering from injuries, as well as compensating for muscular imbalances.

It has been proposed that mono-articular exercises may not provide additional benefits to multi-articular exercises, neither in the short nor in the long term, when training the upper limbs, neither in trained nor in untrained subjects. In addition, carrying out this type of exercise produces greater fatigue without it being reflected in a greater adaptation in strength, and its indiscriminate use can decrease performance (Gentil et al., 2017).

the improvement of the strength in isolation of the muscles involved in a specific specific action can have a negative effect on the result.

However, it is accepted that, for example, localized training of the extensor muscles of the lower back can have a positive effect on specific performance (Gentil et al., 2017). The benefit of this exercise on the lower back is likely, and it is an exercise that has been used for many decades, but the inclusion of the well-performed clean exercise, we believe, could be sufficiently accomplished and with a greater positive effect on performance. in own competition actions.

Free-weight exercises that engage almost all major muscle groups in a coordinated manner, such as Olympic exercises and partials, full squats, jumping jacks, and throws, generate closed-chain movements, which have application or transfer. to most competition-specific gestures.

These free weight exercises improve strength in extensor (and plantarflexion) movements of multiple joints with a wide range of loads. All of these free weight exercises, except squats, are performed at high absolute speed, which may favor the effect on competition gestures, especially those that must be performed at high speed.

The squat, when trained, should also be performed at the maximum possible speed, but the absolute speed will always be lower than with the others, although its transfer to exercises such as jumping or running can also be very high.

Olympic exercises and their partials are characterized by the fact that, due to their technical demands, they must necessarily be performed at high speed (MRI speed around 1 m/s-1) (Gonzalez-Badillo, 2000), with a high degree of of coordination and an important production of force in the unit of time, that is to say, they are very explosive movements by nature when they are carried out with a moderately correct technique.

Jumps and throws have similar effects to the previous ones, but performed with lighter loads. These three groups of exercises have the property of prolonging the propulsive phase in the application of force, so that the braking phase is shorter or does not exist. The squat, when trained, should also be performed at the maximum possible speed, but the absolute speed will always be less than with the others, although its transfer to exercises such as jumping or running can also be very high.

In this post, an exhaustive analysis will be made on why you should not reach muscle failure during training. Publications with several studies in this regard will be reviewed and the drawbacks of this form of training will be added.

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

• For the recruitment of motor units: with a predominance of fast fibers, very important for improving strength —and hypertrophy— and speed of execution, it does not seem necessary to reach muscle failure.
• the maximum volume achievable at the same maximum and average relative intensity does not produce the best results in competitive athletes in snatch, two-stroke and squat exercises.
• A high hormonal environment does not seem to have an influence during the post-training phase of protein synthesis, since hormone levels drop to basal values ​​within a few minutes.
• With less mechanical, metabolic, and hormonal stress—far from muscular failure—strength can be improved to the same or greater extent than reaching muscular failure.
• What has been observed is that more time under tension tends to produce more protein synthesis, but not more force.
• There are several studies in which it is concluded that reaching failure does not provide better results than not doing so.

What is muscle failure and origins

If you consult any text, not only ancient, but even modern, and ancient and modern “scientific” articles, related to strength training, in almost all cases it will be recommended that to improve “maximum” strength is necessary perform the maximum possible number of repetitions in the series. In this situation, you would be facing what is known as “reaching muscle failure”, that is, not being able to do more repetitions than have been done in the series.

This form of training was initially applied in the 1940s, when Thomas L. DeLorme, a US military physician and rehabilitation specialist, was trying to rehabilitate polio patients and war wounded. The idea of ​​training for the maximum number of repetitions in the series came to him from his own experience training “on his own” with weights to recover from rheumatic fevers, instead of on bed rest.

Initially, the training applied to the patients was 7 series of 10RM five times a week. He called this training “heavy resistance exercise” although he soon realized that this load was excessive and changed to “progressive resistance exercise”, which consisted of doing series of 10 repetitions, but not all with the maximum possible load, but a set with 50% of the 10RM, a second set at 75% and a third set at 100% of the 10RM.

If the patient could do more than 10 repetitions in the third set, the weight should be increased. This is “the famous 3x10RM training”, which had a different meaning from what has been understood to date. In fact, what became popular and applied to practitioners of strength training, competitive athletes or not, was 3x10RM, but all at 100 possible repetitions.

That is to say, the interpretation of the proposals of DeLorme and his collaborators was clearly wrong, because, over the years, it has been observed that DeLorme’s second proposal was more rational than the one applied by the majority of specialists in the training of force. For more information on DeLorme’s contributions, see Todd et al. (2012) and González-Badillo et al. (2017).

In the years 40-70 it was not very well known what was the reason why training until muscular failure was effective

Later, during the 1970s, the idea of ​​using training to failure was reinforced with the recommendations of Arthur Jones, founder of Nautilus 4 Sports / Medical Industries and MedX Corporation, who proposed that one series always be done until muscular failure. , 8-12 repetitions, once or twice a week maximum, and at low or controlled speed, because “this is best for improving muscle mass, strength, power, and endurance” (in Smith and Bruce -Low, 2004).

In the years 40-70 it was not very well known what was the reason why training until muscle failure was effective, and since it had not been experimented with other types of training, this effectiveness led to this type of training being considered as the best, and for many the only and necessary way to improve strength… and everything that can be improved.

Over the years, explanations for this apparent effectiveness have been found and up to now some reasons have been given to justify it. However, what is characteristic of these explanations is that they are always linked to the processes that produce or can produce a greater increase in muscle mass or hypertrophy. In other words, justifying training to failure as a way to improve strength is the same as justifying the way to achieve greater hypertrophy, a condition considered practically necessary and proportional to the improvement in strength.

Several comments can be made in relation to the above. The first is that strength improvement is understood exclusively as RM improvement. What happens with the rest of the loads that have to be moved “is not an improvement in strength”. The second is that it seems that if there is no noticeable or detectable improvement in hypertrophy there is no improvement in strength. As seen, these are two approaches that do not conform to reality.

Why is it proposed to train to muscular failure?

The reasons that are proposed to justify the application of muscular failure are, generally, the following:

• the possibility of achieving greater recruitment of motor units,
• the greatest muscle damage,
• increased levels of anabolic hormones,
• the increase in muscle mass,
• the longest time under tension…,

Since all this contributes to the improvement of hypertrophy and, therefore, “to the improvement of maximum strength” (1RM). Some issues related to this proposal are the following.

The possibility of achieving greater recruitment of motor units.

This is considered necessary because “the important thing to achieve maximum muscle activation is to reach failure, regardless of the number of repetitions performed” (Behm et al., 2002). Although, the same authors indicate that more than 20 repetitions no longer seems convenient.

However, for the recruitment of motor units: with a predominance of fast fibers, very important for improving strength —and hypertrophy— and speed of execution, it does not seem necessary to reach muscular failure, because it has been observed that this recruitment can be achieved with 3-5 repetitions less than those necessary to reach muscular failure (Sundstrup et al., 2012), and because, especially, these motor units are recruited without reaching failure if the action it is performed at the maximum possible speed (in an explosive manner) (Desmedt and Godaux, 1977, 1979: Van Cutsem et al., 1998

Since the absolute force at which a motor unit is activated is not fixed and varies with speed and type of activation, which is accompanied by a decrease in the recruitment threshold as force output in the motor unit increases. time (maximum explosiveness) (Desmedt and Godaux, 1977), which is consistent with the observation that most motor units are activated at approximately 40% of maximum load during actions performed at maximum speed (expression of explosiveness) (Enoka and Duchateau., 2019)

Therefore, the motor units of maximum activation threshold can be recruited almost immediately after beginning the exercise if the action is performed at the maximum possible speed, pol o that it does not seem that it is necessary to reach muscular failure to achieve the maximum possible recruitment. of motor units.

muscle damage

Muscle damage, since it will lead to greater degradation and protein synthesis, activation of satellite cells, inflammation, all closely related to hypertrophy. This muscle damage is associated with a high volume of training with medium or high loads, and the more you train, the greater the muscle damage. However, it should be noted that the training effect cannot be based on the proposition that “the more you train the better”, because, among other reasons, it has been observed that an excessive frequency of strength training, which would lead to a greater volume of work, can keep inflammatory processes increased and reduce Akt phosphorylation (Coffey, 2006, doctoral thesis), which which would lead to a decrease or inhibition of the cascade of signals that lead to protein synthesis.

In some studies it has been observed that the maximum volume achievable at the same maximum and average relative intensity does not produce the best results in competitive athletes in snatch, two-stroke and squat exercises (González-Badillo et al., 2005), although in this case none of the three experimental groups even reached muscle failure. Losing 10 or 20% of the speed reached in the first repetition in the series —which means being very far from muscular failure— in the squat exercise better results are produced, especially in actions performed at high speed, than continuing doing repetitions in the series until losing between 40 and 50% (loss close to muscular failure) of the initial speed (Pareja-Blanco et al., 2017; Rodríguez-Rosell, Doctoral Thesis).

Therefore, it does not appear that high muscle damage is necessary to improve strength.

Increased levels of anabolic hormones.

It is true that a higher hormonal level increases the probability of interacting with specific receptors, facilitating the metabolism of proteins and the consequent hypertrophy, and that the interaction with hormonal receptors initiates the cascade of signals or events leading to the alteration of the rate of synthesis. of proteins.

For this reason, when the role of anabolic hormones in training is discussed, it is generally associated with their possible relationship with hypertrophy, which, in turn, is consistent with performing the exercises until muscular failure. However, it has been questioned whether some hormones, such as growth hormone (GH), actually have a significant effect on muscle tissue hypertrophy (Rennie, 2003).

Some studies tend to confirm that in a favorable hormonal environment, the effect of training can be greater than in the absence of it. In this sense, it has been observed that carrying out an exercise that sharply raises the levels of circulating hormones improves the performance in the exercise that follows.

For example, exercising the legs before performing arm exercises (Ronnestad, Nygaarad & Raastad, 2011). This combination of exercises resulted in a significantly greater improvement in arm strength (1RM) and power at 30 and 60% RM (i.e. maximal strength improvement at these relative intensities as well, of course). ) than when the arm training was done without the previous leg exercise.

However, if training with the lower limbs is performed that tends to raise hormone levels after performing an exercise of the upper limbs (group A), no different effect is produced than if only the exercise of the upper limbs is performed (group B).

In this study, conducted with young male subjects, hormone levels after leg training were higher in group A than in group B, but neither were changes in muscle cross-sectional area (AST). and in the different types of fibers neither the increases in force were different between both groups.

These data seem to confirm that local mechanisms are the most relevant in gaining hypertrophy (West et al., 2010) and it is concluded that the subsequent elevation of hormone levels is not necessary to increase anabolic processes in young men. .

Since hormone levels remain high for a few minutes and protein synthesis continues for approximately 48 hours, it is considered that the anabolic effect due to the hormonal environment might not be very high (West 8 Phillips, 2012), and therefore , not having a high relevance in the improvement of strength.

In summary, these studies would indicate that a favorable hormonal environment during the performance of an exercise could have an influence on the improvement of strength, but this elevated hormonal environment does not seem to have an influence during the post-training phase of protein synthesis, since hormone levels drop to baseline values ​​after a few minutes.

In addition to these experimental evidences, it has been observed that in order to improve strength it is not necessary to train until muscular failure, which are the typical trainings that generate a higher hormonal effect (Kraemer et al., 1990), but rather that the effect is superior without that maximum hormonal stress, especially before actions carried out at high speed.

Increased muscle mass

Actually, all of the above is related to the increase in muscle mass. There is a general consensus that a moderate number of repetitions per set and training to muscle failure is the type of training that optimizes hypertrophy (Kraemer et al. 2002).

However, it has also been observed that with lower intensities, such as 30% of the RM, if repetitions are performed in the series until exhaustion, there are also important effects on protein synthesis and hypertrophy. Three series at 30% of the RM to failure can produce a greater increase in quadriceps volume (7%) than one series to failure with 80% (3.5%) and the same as 3 series at 80% to failure. failure (7%) (Mitchell et al., 2012), It is proposed that the rate of protein synthesis depends fundamentally on the recruitment of fibers and not exclusively on the use of high intensities. (Burd, Mitchell, Churchward-Venne, 8, Phillips, 2012).

These results seem to indicate that the mechanical signals for hypertrophy occur primarily in individual fibers, and that when low loads are used, but repetitions to exhaustion are performed, type II fibers are recruited. However, greater volume gain does not seem to necessarily translate into greater strength gain.

The described training produced greater improvements in knee extension RM in the two 80% than in the 30% RM groups, and equivalent changes in moment of force (Mitchel et al., 2012). Returning again to the most current and controlled studies (Pareja-Blanco el al., 2017), it has been possible to verify that almost reaching muscular failure (losing 40-45% of the speed in the series in the squat exercise) It produces a greater increase in muscle mass and in the percentages of changes from faster fibers to type II, but no greater improvement in strength at any speed or relative load.

To conclude, muscle mass is positively related to the force that a muscle can generate, but the results of well-controlled studies on the magnitude of the training load and the extent of its effect indicate that it is not necessary to train to produce the force. greatest possible muscle mass or condition or key to improving strength, because with less mechanical, metabolic, and hormonal stress—staying far from muscular failure—strength can be improved to the same or greater extent than reaching muscular failure.

Longer time under tension

In relation to the previous factors, this proposal is based on the fact that training until muscle failure at a certain relative intensity will subject the muscle to a longer time of tension or activity than if it does not reach failure, which would correspond to an average speed minor. It is considered that this may mean a greater stimulus for the muscles, which in theory could increase the possibility of adaptation in strength and hypertrophy.

Consequently, the complementary argument to this is that when doing a movement at a higher speed you cannot apply as much force as if you do it slowly, which would give rise to a smaller effect on the improvement of strength. Neither of the two ways of expressing this justification seems reasonable or serves to explain the effect of time under stress.

In the first place, regardless of whether or not the time under tension (TBT) is a decisive factor as an adequate stimulus to achieve better adaptations, it must be considered that the increase in TBT can occur, fundamentally, in three different ways that would be decisive in regarding the type of stimulus and the effect they produce, although not all of them would allow assessing the effect of TBT.

• The first of these consists of doing a greater number of repetitions in the series —usually until muscular failure— at the same relative intensity (higher TBT), always at the maximum possible speed, compared to doing fewer repetitions in the series (lower TBT). ).
• The second is to do the same number of repetitions at the same relative intensity, but, in one case, intentionally not doing them at the maximum possible speed (higher TBT) versus doing them at the maximum possible speed (lower TBT).
• And the third is the increase in relative intensity for the same number of repetitions, which means, for example, that the TBT with 30% of the RM to do 3 repetitions at the maximum possible speed would be much lower than doing the same repetitions with 90% at the maximum possible speed.

In all the forms indicated, the TBT is different in the two options described in each case, but only the second form would be useful to be able to really compare the effect of the TBT, since in the first the number of repetitions is different and in the third it is introduced the intensity variable, a factor that can have an important influence on the adaptation process, so that the TBT would not be the main or the only one responsible for the final effect.

What has been observed is that higher TBT tends to produce greater protein synthesis, but not greater strength. The study mentioned in the previous point by Mitchell et al. (2012) is an example of how a higher TBT by doing 3 sets to failure with 90% RM (higher TBT) produced greater muscle mass gain but less strength than reaching failure in a set with 80% RM. % (lower TBT), and even less strength but the same muscle mass as 3 series at 80% (intermediate value of TBT).

longer time under tension tends to produce greater protein synthesis, but not greater strength

This is a clear example in which there are difficulties to adequately assess the effect of TBT, since failure is reached with different relative intensities and with different TBT and effects. In another study, exercising at 30% RM to exhaustion slowly (6 s in knee extension) produced greater mitochondrial, sarcoplasmic, and myofibrial protein synthesis than doing the same number of repetitions with 1 s in each knee extension. No information is given about strength (Burd et al., 2012). In this case, there is the drawback that when training at 1 s per knee extension, the exercise was not performed until exhaustion. Therefore, it is observed that it is difficult to find the appropriate conditions to assess the effect of TBT in isolation.

The argument that moving the same load, absolute or relative, at a higher speed means that less force can be exerted and, therefore, less adaptation effect does not seem reasonable. The speed at which the same given load moves will be greater the greater the force applied to it.

Spending more time displacing the same load may add more time for the application of force and muscle activation, but with very low peaks of force, so the initial impulse, which determines the speed of displacement, that is, performance, will be much less. . For this reason, it has been proposed that the determining factor to improve performance, especially in high-speed actions, should be the impulse generated in each action (Crewther et al, 2006), not the time that force is being applied.

As indicated, the second way to increase TBT is the one that really allows us to assess the effect of TBT on strength. With the intention of verifying the effect of doing the movements at the maximum speed possible (lower TBT in this case) or at half that speed (higher TBT), two studies were carried out in which a group performed the training at maximum speed. possible (G100) in each repetition with the maximum load of the day and another at 50% (Gso) of said speed.

analysis of studies on muscle failure maintaining constant effort

One study was conducted with the bench press exercise (González-Badillo et al., 2014) and the other with the squat (Pareja-Blanco et al., 2014). In both cases, they trained 3 times a week for 6 weeks, and the maximum intensity of each session ranged between 60 and 80% of the RM. With these intensities, 3 series were made from 8 to 3 repetitions per series, all very far from muscular failure.

The speed and the execution time were controlled in each repetition. The relative intensity was adjusted in each session based on the average propulsive speed expected for the first repetition of the maximum load of each session. The TBT (execution time in the concentric phase of each repetition) was significantly higher in the G50 than in the G100 in both exercises (360.9 s vs. 228.8 s in the bench press and 383.5 s vs. 260 .5 s in the squat), but the improvements in all the variables indicating strength were significantly greater in the bench press, and in the squat there were greater percentages of improvement and effect sizes in all the variables and even a group x significant measure interaction in favor of the G100 in the vertical jump (CMJ) exercise, an exercise that was not trained.

All of these apparently justifying processes for the need for muscle failure to improve strength are related to the degree of mechanical stress, which is the basis for muscle activation to generate a series of chemical, electrical, and mechanical signals that cause a response. multiple physiological that culminates in the degradation and expression or synthesis of certain specific proteins that give rise to the adaptation of the organism to the type of stimulus received.

In this way, when exercises that are commonly known as strength training are performed, muscle tension tends to be produced, which generates a cascade of molecular processes that contribute to activating positive muscle hypertrophy signals and inhibiting muscle atrophy signals. Naturally, the degree of “tension” must have an appropriate value so that the processes of degradation do not exceed those of protein synthesis.

However, excessive stress could give rise to negative effects that explain why from a certain degree of fatigue or a certain degree of muscular approximation, the effects could be null or even negative for performance, especially for actions carried out at high speed. speed.

Among these factors could be: producing a significant reduction of ATP with high levels of ammonia; excessive muscle damage, with prolonged inflammation processes, with probable inhibition of protein synthesis and reduction of elasticity due to damage to intramuscular elastic structures; reduce the production of anabolic hormones such as testosterone, which would require a longer recovery time between sessions; produce interference with the specific training, due to excessive fatigue and the performance of a high number of requests at low and very low speed during “strength” training…

On the contrary, less fatigue, always performing the actions at the maximum possible speed and with a high average absolute speed during each session, could favor other mechanisms that tend to produce strength improvement without the side effects of reaching muscle failure. , such as the recruitment of fast twitches without excessive fatigue; the stimulation of the synthesis of fast fibers, which would mean a greater efficiency of release / removal of calcium in muscle activation; the non-significant reduction of the percentage of the fastest fibers to the slowest; the greater percentage increase in the cross section of fast fibers and, in all probability, the improvement of neural adaptations: recruitment, synchronization, stimulus frequency, intermuscular coordination.

Since the 1980s, it has been maintained that reaching or approaching the maximum achievable volume in the session, week, month or training cycle does not offer the best results.

Since the 1980s it has been maintained that reaching or approaching the maximum volume achievable in the session, week, month or training cycle does not offer the best results. In 1985 and 1986, a study was carried out in which the effect of doing different volumes was compared with the same maximum relative intensities of each session and the same average relative intensities of each session, week and complete training cycle (12 weeks). ) with competitive athletes and strength specialists (weight lifters).

Subjects performed three different volumes:

• One group reached the maximum volume that they had observed in practice that the subjects could support without reaching extreme fatigue that prevented them from continuing the training (G100),
• A second group performed the same training in terms of maximum and average intensities, but with 85% of the volume of the previous group (G85),
• A third group, also at the same maximum and mean intensities, performed only 65% ​​of the volume of the maximum volume group (G65).

The results showed a curvilinear trend between training volume and performance in the snatch, double jerk, and squat exercises. This tendency means that the G85 tended to obtain the best results, and the G100 and G65 groups obtained similar results. This study carried out in the 1980s, part of Professor Badillo’s doctoral thesis, and was published a few years later (González-Badillo et al., 2005).

The results of this study were included in the 2009 Guideline and “the American College of Sports Medicine (ACSM) in presenting its guidelines for strength training, stating that “greater volume does not appear to offer better benefits”, although , then they ignored the results and continued to recommend the classic XRM

Regarding the repetitions to be performed in the series (failure or no failure), for more than 25 years, it has been proposed that it is probably enough to reach a maximum of half of the possible repetitions in the series to improve strength performance. in most sports specialties and athletes.

The first application of this idea in a sport other than Weightlifting was with the women’s national hockey team —Olympic champions in Barcelona-92— at the beginning of the 90s. Over more than two and a half years, the team improved leg strength (improved full squat), jumping ability, acceleration, and threshold speed (commonly called anaerobic threshold or second lactate threshold) rdoing training, especially full squats, with loads lower than 80% of the RM and with less than half of the possible repetitions in the series.

In the early 2000s, this idea was applied in the experimental setting and training sessions were designed to compare the effect of reaching muscle failure or not (Izquierdo et al., 2006). One group would reach failure with 3 sets of 10 reps and the other would do half the reps possible in the set and 6 sets to equalize the total volume.

At the beginning of the 2000s, this idea was applied in the experimental field and training sessions were designed to compare the effect of reaching muscular failure or not.

This equalization of the volume was always considered unnecessary, but sometimes the demands of the publications force to modify the designs somewhat. In this study it was found that it was not necessary to reach muscular failure to achieve the same or better strength performance. Subsequently, a study was designed in which the volume was no longer matched, once again doing one group half the repetitions of the other (Izquierdo-Gabarren et al., 2010), once again obtaining higher effects in the group that trained with half of the possible repetitions in the set versus reaching muscular failure.

Naturally, these last studies can be considered relatively well controlled, because they were based on the initial criteria to determine the nature of the effort made in a series, estimating the relationship between the repetitions performed and those that could be done in the series. But when you can really talk about the true effect of training to failure or not is when you could start to control the load through the speed of execution, which allowed you to know with very high precision what the absolute load (weight) represented actually the relative intensity programmed for each session, as well as the degree of effort to which the subject was subjected in the series through the control of the loss of speed in the series.

This made it possible to eliminate from the design the number of repetitions to be performed in each series, one of the classic variables of any study that has sought to know the effect of the so-called “strength training”. Therefore, today, if the speed of each repetition can be adequately measured, it does not make sense to program the repetitions to be carried out in the series, because if they are programmed, each participant or athlete could be making a different effort.

it does not make sense to program the repetitions to be carried out in the series, because if we program them, each participant or athlete could be making a different effort

That is, to equalize the volume performed by different experimental groups, something apparently necessary “to control a possible intervening variable in the design, what it does, precisely, is to introduce a foreign variable into the design itself, since the same number of repetitions in the series before the same relative intensity can mean a different effort or degree of fatigue for each subject, since not all subjects can perform the same number of repetitions before the same relative intensity (González-Badillo et al., 2017).

Therefore, If the loss of speed in the series is taken as a reference, and is programmed as an indicator of the training load, and not the number of repetitions in the series, it will be achieved that, before the same relative intensity, the subjects of the same experimental group have made a very similar degree of effort throughout the training cycle, as well as that another or other experimental groups have made really different efforts.

This control of the effort made is what really determines the degree of load and what is interesting to control, if one wants to know the effect of certain types of training loads.

These advances in the control of the training load have allowed us to confirm through several experimental studies carried out in the last 10-15 years that, indeed, a fatigue far removed from that which corresponds to muscular failure tends to offer better results than reaching to failure.

fatigue less than that corresponding to muscular failure tends to offer better results than failure.

In summary, the results of these studies indicated that losing between 10 and 20% of the speed of the first repetition in the series in the full squat exercise, that is, doing half or less than half of the “repetitions possible in the series (very far from muscular failure), with subjects familiar with strength training, always executing the exercises to the maximum possible speed, with intensities between 70 and 85% of the RM, for 8 weeks at two sessions per week, offers better results in trained and untrained exercises than losing 30% or practically reaching failure, with losses of 40-45% speed in the series (Pareja-Blanco et al., 2017: Rodríguez-Rosell, Doctoral Thesis).

Similar results have been found when comparing three groups with losses of 10, 30 and 45% of the speed in the series in the squat exercise with intensities between 55 and 70% of the RM. The 10% loss offered the same or better results in the trained and untrained exercises than the 30% loss and, especially, the 45% loss (very close to muscular failure) (Rodríguez-Rosell Doctoral Thesis).

In the bench press exercise, with intensities of 70 to 85% and losses of 15, 25, 40 and 50%, the effects also tended to be higher with losses close to 30-40% of the speed loss compared to the 50%, loss very close to muscle failure. As can be deduced, these studies are the ones that offer the best guarantees that, indeed, the subjects trained with the relative intensities and the programmed degree of effort or fatigue, which allows us to confirm that the training until muscular failure (maximum or almost maximum loss of speed in the series) do not offer better results than lower losses of speed, even reaching a very low degree of fatigue, such as losing only 10% of the speed in the series.

Losing 10% speed in the squat set at intensities from 70 to 85% means that subjects did, on average, between 3.3 and 2 repetitions per set, when the repetitions possible, on average, at these intensities They range from 10.2 to 5. In other words, there were always far fewer repetitions than half of those possible in a series.

This caused the total repetition volume of the training cycle to be less than the volume of the group that reached near failure. With the 20% loss, the repetitions per series performed were, on average, from 5 to 2.7, practically half of those possible. With these intensities and in this exercise, doing more than half of the possible repetitions in the series (from losing 30% of the speed in the series) already begins to have less positive effect on performance, especially in actions performed at high speed. speed.

Apart from those mentioned, there are already several studies in which it is concluded that reaching failure does not provide better results than not doing so, but unfortunately, most of these studies are not based on designs that really allow us to conclude the advantage of not reaching failure. failed. One of those that comes close to confirming that reaching it is carried out by Sampson and Groeller (2016), who apply training to failure (6 repetitions with 85% of the RM) or doing only 4 repetitions with this relative intensity — this really means a very high effort character and, therefore, with a very high loss of speed in the series, that is, close to failure — it was confirmed that after 12 weeks of training with the exercise of elbow flexion, the effects do not depend on the number of repetitions performed to failure, nor is it a necessary condition to reach it, at the same time that it is not necessary to equalize the volume to obtain the same results in strength, muscle activation and in the cross-sectional area of ​​the muscle.

There are already several studies in which it is concluded that reaching failure does not provide better results than not doing so.

In addition, in this study, the group that performed the movements at the maximum speed possible in the concentric phase and in a controlled manner (2 s) in the eccentric phase, reduced the activation of the antagonist muscles (triceps), which suggests — it is a personal deduction, not that of the study authors, that this may be an execution strategy that favors concentric actions performed at the maximum speed possible. However, this study, which is one of the most adjusted to verify the effect of failure compared to no failure, has the drawback that the stimuli were very similar, so it is logical to expect that the results were also very similar.

In other words, although the results favor “the hypothesis of not reaching failure”, the study leaves a wide field of uncertainty about the minimum load that could be equivalent or superior in its effects to the load that represents muscle failure. The answer to this uncertainty can be found in the series of studies presented in the two previous paragraphs, in which you can see the progressive tendency to decrease performance from certain values ​​of: degree of effort / loss of speed in the series / degree of fatigue / decrease in average training speed / increase in volume.

Disadvantages of programming and training with the classic XRM or nRM

On the other hand, in a recent review, Davies et al. (2016) conclude that a similar increase in strength can be obtained without reaching muscle failure as reaching it. Programming, expressing and performing the training through the classic XRM or nRM, apart from the fact that you probably won’t get the best performance benefits, It has a number of drawbacks:

It is based on the mistaken idea that being able to perform the same number of maximum repetitions before the absolute load that corresponds to each subject means that you are working with a certain relative intensity or percentage of 1M, since each percentage of 1RM can be performed , on average, a certain number of repetitions.

On the other hand, doing the same repetitions with a certain load does not mean that you are working with the same percentage. The maximum value of the range in which the number of repetitions performed at the same intensity is found, from 50 to 85% of the RM, can double the minimum value, with an average coefficient of variation of -20% (González-Badillo et al., 2017). Therefore, two subjects who have trained with the same number of maximum repetitions per set may have trained with very different relative intensities.

two subjects who have trained with the same number of maximum repetitions per set may have trained with very different relative intensities

It is not realistic to propose a training such as: 3x10RM, which means that the subject must perform 3 series of 10 repetitions with a load (weight) with which, in the first series, they can only really perform 10 repetitions. No one person can perform this workout, because they will never be able to perform all three sets of 10 repetitions with the same absolute load.

Sometimes it is proposed that as the series is done, the load is reduced in order to reach the programmed repetitions, which is even more unrealistic, since it is not possible to know “what exact weight must be reduced” so that they can be done precisely. the repetitions predicted in the previous fatigue.

Always training with the maximum number of repetitions possible per series, even if fewer repetitions were done in successive series with the same weight, can produce at least the following negative effects: excessive fatigue, increased risk of injury and reduced execution speed before any load (high loss of speed in the series). All this can lead to reduced sports performance.

From the foregoing, it can be deduced that it would be very reasonable for no XRM value to be measured, neither for training nor to assess the effect of training.

When speaking of “squat” it refers to the full or deep squat exercise. This article will review the squat in detail as it is well known that the squat is an exercise that directly strengthens the quadriceps, hamstrings, glutes, erector spinae, and triceps surae. Apart from the fact that it involves a series of synergistic muscles that contribute to the execution of the exercise and balance.

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

• Squats will do more to prevent knee injuries than any other exercise.
• If the exercise is performed with a correct technique, it is trained progressively and supervised by experts in the training of this exercise, the squat is presented as a training to protect against injuries and improve the strength of the lower extremities.
• The squat is the main exercise that can be practiced by any athlete who wants to improve their physical performance by doing any exercise that is not the actual practice of the specific exercise.
• Healthy non-athletic users would still have less risk because the loads used, the frequency of training and the stress would be much lower.

It has also been possible to verify through the studies analyzed in this text that it has a significant effect on the ability to jump and acceleration. In fact, it has been proposed that higher sprint performances are achieved by greater application of force against release, not by more rapid leg movements (Weyand et al., 2000).

Naturally, this greater applied force can only be achieved by improving the strength of the previously mentioned muscle groups, as momentum in the stride is directly dependent on the strength of the gluteals, hamstrings, triceps surae, and quadriceps. From the functional point of view, when comparing the effect of training the squat, half and quarter squats, only the squat could be considered as an effective exercise to improve strength, because only the degree of flexion of the squat provides the morphological and neural stimuli required for the hip and knee extensors to positively influence acceleration processes (Hartmann et al 2012).

only the squat could be considered an effective exercise to improve strength

In another study in which the effect of training with loads from 60 to 80% of the RM was compared in the squat, the squat to the parallel and the half squat. This means that executing the squat exercise allows an effect that is even above the effect due to the specificity of the exercise itself evaluated. In addition, the squat had the greatest effect in CMJ, 20m run and Wingate test, while the half squat did not improve in any of these three variables and was the only one that experienced a significant increase in the physical disability test (pain, rigidity, functional disability) (Pallarés otal.. 2019)

Traditionally it has been considered that the squat was detrimental to the knee joint, but this does not seem to be very justified. Escamilla (2001) concludes that the squat (to parallel) does not compromise knee stability and can properly reinforce stability. Although he still has reservations about flexing anything more than parallel.

Its embargo, Hartmann et al. (2013) consider that with greater flexion of the knee joint, a displacement of the contact areas of the knee components occurs with a continuous enlargement of the retropatellar articular surface, which leads to lower retropatellar compressive stresses. .

Both menisci and cartilage, ligaments, and bone are susceptible to anabolic processes and structural adaptations to their function in response to increased activity and mechanical stress. Therefore, concerns about degenerative changes in the femoral tendon complex and the apparent increased risk of chondromalacia, osteoarthritis, and osteochondritis due to the squat are unfounded (Hartmann et al., 2013).

It must be taken into account that for the same relative load, when doing the half or quarter squat, the pressure on the joints of the back, hips and knees is much greater, so the risk of excessive stress is also applied. is.

squats will do more to prevent knee injuries than any other exercise

Parker (1992) says: “squats will do more to prevent knee injuries than any other exercise” (p.28). And he continues: “many trainers believe that squats are dangerous for the knees. Nothing is further from reality”. Squats are a staple exercise in the New York Giants (the football team this author coaches) program, and will be for sure in the future.

Poliquin (1992, p. 28), in making the initial diagnosis before planning the training of Jadson Logan, hammer thrower, found that the athlete had been plagued with knee pain for the past eight years. This pain was caused by the continued use of the so-called “safe squat”, “safe squatting”, that is, by the half squat.

To avoid this, this type of exercise was changed to the full, deep squat: the posterior part of the thigh had to cover the calves at the deepest moment of flexion. After six weeks of training, the athlete reported no pain, improved his position in the hammer throw twist, and achieved better results than ever in the vertical and horizontal jump.

Therefore, if the exercise is performed with a correct technique, it is trained progressively and supervised by experts in the training of this exercise, the squat is presented as a training to protect against injuries and improve the strength of the lower extremities.

Contrary to popular belief, the squat does not contribute to increased risk of passive tissue injury (Hartmann et al. 2013). Given its positive effects for carrying out practically all sports actions in which the legs are involved and its protective effects against possible injuries, the squat is the main exercise that any athlete who wants to improve their physical performance by doing any exercise other than their own can practice. practice of the specific exercise.

The squat is the main exercise that any athlete who wants to improve their physical performance can practice.

Regarding the way to perform the squat, a series of considerations must be kept in mind, a squat can be considered complete if it is exceeded, even slightly; the horizontal of the thigh with respect to the ground. That is, it is not necessarily about forcing the maximum possible flexion.

The greater or lesser flexion will depend on the joint mobility of each subject, and it is never recommended that the flexion be the maximum possible if the subject has high joint mobility. Therefore, in all cases, and especially in subjects with some joint laxity, due to their low muscle-tendon rigidity, it should be recommended that the last degrees of flexion are not reached and that the subject not relax in this phase, losing the correct posture of the lumbar zone, which must remain straight throughout the execution of the movement, nor that it make a marked “rebound”, excessively fast, at the moment of the eccentric-concentric transition.

On the other hand in the flexion phase (eccentric phase) in its entirety a high speed must not be reached.

Another important aspect is the load with which this exercise should be trained. As a training exercise, you should never perform a squat with the maximum load (1RM), nor a training or an estimation of strength with the maximum possible number of repetitions per series (the “famous” 6RM, 8RM, 10RM, 15RM. ..) That is, the “character of the effort” should never be the maximum.

Nor should MRI be used as an initial test to program training. For this, as indicated, the execution speed is taken as a reference, and in the event that it cannot be measured, the guidelines in this article must be followed and applied in relation to what to do when the speed of execution cannot be measured. execution.

Throughout the text, extensive information is given on the loads for training this exercise. Most of the exercises that are carried out in sports produce significant stress on the knees. Practicing sports as diverse as alpine skiing, soccer, hockey, tennis, jumping, weightlifting, badminton… and many others cause much higher stress than a full squat performed correctly and with the proper loads.

Moreover, many of the injuries that occur in these sports, except weightlifting, may have a lot to do with the weakness of the muscles that protect the knee, which can be correctly stimulated with the deep squat. Whoever considers that this exercise is not suitable for someone or something is in charge of showing the reasons.

Extensive experience using this exercise, apart from studies aimed at analyzing its mechanics, risks and effects, favorable, in some cases, as a means of protecting against injuries, allows us to affirm that there is no reason to justify against its use, and that However, there are reasons to apply it to the entire population that practices sport.

Healthy non-athletic users would still be at lower risk because the loads used, training frequency and stress would be much lower. Obviously, if you suffer from a knee injury, the situation would change, but the experience of having applied this exercise to athletes (top-level soccer players) with great benefit for the recovery of injured knees and cruciate ligament surgery is taken into account.

The squat is the main exercise that any athlete who wants to improve their physical performance can practice.

Other athletes to whom this exercise has been applied with great success for their sporting results and without a single case of injury or discomfort in the knees during a long time of training, were, for example, the national track cycling team ( speed), who went from being able to perform approximately a squat with 105-115 kg in some cases, or 150-160 kg, in another, to being able to move 160-170 and 190-200 kg, respectively, improving their performance in competition . No athlete presented the slightest knee problem.

During all this time, neither 1RM nor training with a “maximal effort character” was ever performed. The women’s field hockey team (1992 Olympic champion) trained with this exercise for three years, each year improving their vertical jump, their time in 15-30 meters and their threshold speed (the so-called second lactate or anaerobic threshold) were runners-up in Europe (lost final on penalties) and there was not a single knee or back injury.

The training carried out was even less stressful than in the case of the cyclists. Other examples with the same results are soccer players who have participated in World Cups and other top-level youth of their ages, top-level volleyball players, or 400-meter runners.

Conclusions about the squat

As a summary of the advantages of the squat exercise, the following is indicated:

• During the full squat, the full range of motion is used in the sagittal plane of the knee and hip joints and quite a bit of range of the ankle. This causes all the components of the connective tissue of said joints to be stretched, thereby giving these tissues stimuli to adapt to great stresses at angles of extreme magnitudes, which probably improves the rigidity of these tissues in extreme displacements.
• The use of full ranges of joint movement probably leads to the distension of the sarcomeres in the most homogeneous way possible before a shortening, accustoming the system to make the “strong” sarcomeres work against the “weak” ones, so that the whole of the fiber (or muscle fibers) get the most out of it.
• Activating a fiber in different ranges of stretching provides advantages when it comes to obtaining the best moments in the length-tension curve of each fiber, especially in penneate (non-linear) muscles. As well as the possible increase in the length of the fascicle, due to the contribution of sarcomeres in series.
• When a fiber is stretched beyond its normal range, the risk of breaking some Z line and, above all, some T tubules increases, which would lead to local contractures within a fiber and an increased risk of total fiber rupture. But the fact of accustoming it to working in wide ranges of stretching probably adapts the sarcolemma and, therefore, the tubule system itself to work in those conditions with less risk of complete fiber rupture.
• Probably the degree and form of the recruitment of motor units within a muscle is different depending on the range of movement, one of the reasons is that at different moments of force, different recruitment and synchronization requirements, due to the participation of large muscle groups of coordinated way.
• The articular cartilages and menisci are maintained thanks to the stimulus that Ssupposes the rubbing of a load, intermittently, on them. When you only work in a short range of movements, a part of the cartilage stops receiving adequate stimuli and before a sudden shock in the less stimulated region it can be injured. Something similar, but with tensions instead of pressures, happens with the ligaments. Today it is known that the innervation of the ligaments is important to maintain the tone and hypertrophy of some muscle groups of the joint in which the ligament is located. The stimulation positions of the ligaments are not exactly known, but it is known that they work in joint positions in which the muscles have little to do (this seems to be precisely one of their functions, that the muscles can relax in certain angular positions). of the joint) It is also likely that when working in positions with a wide range of joints, the synergy of action between ligaments and muscles (especially of the elastic elements of the latter) increases.

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”.

Osteoporosis is a disease characterized by structural deterioration and low bone mass density, which increases fragility and increases the risk of falls and traumatic fractures. However, there are exercises for osteoporosis that can help prevent it, and here we talk about them.

If you don’t already know Fitenium is a free, mobile and video-based social network for users who train strength and/or body weight exercises. At Fitenium users can find free personalized routines, follow their performance, compete and get discounts at nutrition stores and sports equipment. Download it here.

What causes osteoporosis?

Various causes that affect the development of osteoporosis include dysfunction of the menstrual cycle, low energy availability (low calorie intake), being underweight, and a sedentary lifestyle.

Osteoporosis also occurs in men, but in sports there is a combination of causes that can have a significant impact on the development of osteoporosis in women. Eating disorders and absence of menstruation. These two factors, along with osteoporosis, make up what is known as the latriad for female athletes.

Athlete without menstruation or loss of menstruation: everything you need to know

The athlete’s triad has been established as a condition in which a combination of eating disorders and weight loss accelerated by sports practice causes irregularities in the menstrual cycle. This condition promotes the progression of osteoporosis and other medical conditions due to the close relationship between the hormonal environment and bone density.

Therefore, it is important to know how to identify the signs and symptoms that can lead to these situations, such as fatigue above normal, weight changes and changes in the menstrual cycle. In general, sport should be a factor against osteoporosis, so choosing your osteoporosis exercises correctly is key.

How can I train to improve bone mineral density?

The first thing to know is that sedentary lifestyles and inadequate energy intake are one of the main risk factors for the development of osteoporosis, especially in postmenopausal women.

Therefore, make sure that you are an active and well-composed person throughout your life, as you are much less likely to contract this disease.

Lifelong physical activity helps prevent osteoporosis

First of all, we have to understand what exercises for osteoporosis should be done to strengthen our bones:

• Traction exercises such as those that occur when our muscles are stretched.
• Push exercises such as gravity itself or multiple impacts that occur during execution.

The traction stimulus primarily stimulates cortical bone. It is the densest, superficial and metabolically least active, so it has a much lower turnover rate than bone. The compression stimulus further stimulates the cancellous bone. Cancellous bone is internally and metabolically much more active, with a much higher turnover rate than cortical bone.

Osteoporosis, in particular, has a significant impact on bones that have a high proportion of trabecular tissue (vertebral or upper thigh). This is because it is metabolically active and is more susceptible to hormonal changes. That is why in the case of osteoporosis, recommended exercises are the squat or the deadlift, which help maintain bone density throughout life.

What kind of exercises for osteoporosis should I do?

To summarize the above, it is necessary to combine exercise with a traction stimulus to the bone and exercise with a compression stimulus. The solution is strength training and small micro-impact exercise like high-speed walking, steps, and vibrating machines.

For strength training, choose multi-joint exercises for the lower and upper body. A list of osteoporosis exercises would be, for example, squats and their variations, deadlifts and their variations, bench press or dumbbells, military press or shoulder press, dumbbells, jerks or basses.

The key to micro impact training is progress. Start by walking on a steep treadmill that compresses less than on a flat surface, then move on to stepping and vibrating machines. In the latter case, it is always better to use it under the supervision of an expert.

The other day we looked at how age affects body composition, correcting it even if there are no weight changes, and sport is the best preventive and therapeutic agent present in diseases such as osteoporosis. I was talking about it. Today we will talk about what older people can do in the gym to improve their health and quality of life.

If you don’t already know Fitenium is a free, mobile and video-based social network for users who train strength and/or body weight exercises. At Fitenium users can find free personalized routines, follow their performance, compete and get discounts at nutrition stores and sports equipment. Download it here.

What is the third age?

In general, we understand people over 65 years of age at three years, but some authors distinguish between two non-aging periods at this stage of life.

The third age begins almost when the person leaves work and ends when social dependency arises. The fourth age begins at the end of the previous stage and lasts until death.

What kind of physical activity should older people do?

One of the great evils that plagues our society today is the sedentary lifestyle. This is a risk factor that extends from childhood to the elderly.

This is because the loss of age and capacity tends to increase the sedentary and meditative lifestyles of older people, especially if this person has never been physically active before. It is an even greater risk factor.

Assessing a person’s health is a reliable indicator of health and life expectancy. Therefore, prescribing a training plan for older people that focuses on the development of strength, aerobic capacity and flexibility is a very important tool to reduce the risk of cardiovascular death. Of factors and all causes, without considering health savings.

Therefore, these individuals should focus on strength and aerobic training to improve or minimize flexibility.

What is the ideal dose for each type of exercise?

According to the American Sports College of Sports Medicine and the American Heart Association, the following are recommended:

At least 5 days a week, 30 minutes of moderate-intensity aerobic exercise, or at least 3 20-minute days of vigorous-intensity days.

Two days a week of programmed and sequenced strength training, including 8-10 exercises with 10-15 iterations on a scale of 5-8 Perceived Exercise (RPE).

Hold the pose for 10-30 seconds for at least 2 days and focus on improving joint mobility through active or passive flexible exercise. Yoga is a very good option.

What kind of exercise can seniors do in the gym?

Any of the exercises is prescribed according to the physical condition of the particular person. As a general rule, there are no contraindications, but the lack of mobility and coordination may require the use of adaptations or variations in basic exercises. We want to improve the quality of life and functional independence for these people, so if you can do goblet squats or goblet box squats, you don’t need to do back squats.

Ideally, choose a free-weight jointed exercise that mobilizes your major muscle groups. As mentioned above, designing a training program for exercise patterns is a great option, so here are the main exercises and some alternatives that these people can perform.

Horizontal pushing movement such as dumbbell press. For complex cases, you can choose a horizontal press machine.

Upright pushing movement like a dumbbell shoulder press. Some machines perform this movement pattern.

Horizontal pull movements such as rowing a barbell or winding a rope.

Vertical traction movements such as chest pull.

Knee dominant exercises like squats and leg presses.

Waist-dominant movements such as the Romanian bar and dumbbell deadlifts.

When we talk about leading a healthy lifestyle, we are all thinking about eating right and exercising regularly. However, a healthy lifestyle also includes aspects such as good hygiene, in this case maintaining good oral health.

If you don’t already know Fitenium is a free, mobile and video-based social network for users who train strength and/or body weight exercises. At Fitenium users can find free personalized routines, follow their performance, compete and get discounts at nutrition stores and sports equipment. Download it here.

Impact of oral health on performance

Since the 1968 Olympics, there has been a link between elite athletes and the oral health of the poor.

According to a systematic review, 28% to 40% of athletes say that their oral health affects their quality of life and 5% to 18% of their performance. Oral health is also one of the factors that determine the quality of life.

There is little evidence on how diseases such as caries, periodontal disease, and periodontitis negatively affect quality of life. And the impact in this area can make a big difference in the performance of that sporting elite.

Published on Unplash by John Fornander

Pain, systemic inflammation or the impact of an athlete on the social environment may be part of the cause of poor performance due to poor physiological adaptation to training or its poor quality.

Why is the athlete’s oral hygiene deficient?

With very few studies available, it is difficult to establish one or more strong causes. Still, it is almost impossible to design a good study that can answer this question.

High carbohydrate intake, especially from gels and sports drinks, is speculated to be one of the nutritional causes of diseases such as dental caries in elite athletes. It is also said that eating disorders can cause vomiting and damage enamel, especially in light weight sports such as gymnastics, boxing and horse riding.

Another cause that can contribute to the appearance of these diseases is oral dehydration during sports. Saliva has a moisturizing and remineralizing effect, deficient in the aforementioned carbohydrate drinks and below, which increases the diffuse effect on teeth.

What can you do to keep your teeth healthy?

For the nutritional habits of elite athletes, it is difficult to make a difference because training performance depends on these habits, but regular visits to the dental office prophylactically are good oral hygiene.

For amateur practitioners, it is important to maintain oral hygiene habits, as an overdose of sugar and acidic drinks and poor oral hygiene can cause a variety of diseases.

After all, the best medicine is prevention. This is because many drug models are treatment-based and treatment-based, but not prevention-based, which is detrimental to both patient health and societal health costs.

Gwyneth Paltrow is a well-known actress and a beautiful woman with a lot of style, but every time she opens her mouth to talk about her health, she causes a huge scandal, and for good reason. His advice and ideas are crazy and ridiculous, so it wouldn’t be funny if it didn’t harm your health. Because when you’re a public figure with some influence, you’re also responsible, and Paltrow is completely irresponsible.

If you don’t already know Fitenium is a free, mobile and video-based social network for users who train strength and/or body weight exercises. At Fitenium users can find free personalized routines, follow their performance, compete and get discounts at nutrition stores and sports equipment. Download it here.

His recent events still shock us: the coffee enema. Yeah, how does it sound? His pseudo-health website, Goop, recommends that you probably insert coffee into your rectum to enhance the detox process for a reasonable price, perhaps $135.

coffee enema

It’s so ridiculous I don’t know where to start. Let’s take a look: there is no evidence that the coffee enema has any beneficial effects on all body types. There have been cases of intestinal damage and perforation in enema application and pseudotherapy, including enema (introduction of material through the rectum appears to be generally highly recommended by Sharattan).

Coffee, better by mouth

In addition, Fitenium will never get tired of repeating itself, so it is not necessary to introduce a detox treatment into the body. The liver and kidneys are the organs responsible for this task and have performed it for thousands of years. Whenever you need help, believe us that what you need is a doctor and urgent, not a miraculous pseudoscientific treatment.

Of course, this doesn’t surprise us, since Paltrow has spent years promoting the strangest and most unwarranted things.

Vaginal steam bath

Drink coffee from the rectum and vaporize it in the vagina. In theory, it cleanses the uterus and restores the balance of the female horn… I’m going to be direct on this matter, do not vaporize the vagina

First, it puts a very sensitive mucous membrane at risk of a very dangerous and painful burn. If continued, the pH of the skin and vaginal wall can change and fungi and bacteria can grow. Finally, when the vapor reaches the uterus, foreign microorganisms are also introduced there, which can cause infection.

But perhaps the bloodiest is the suggestion that the womb is dirty and needs to be cleaned. Ms. Paltrow, the human body has its own waste management process, and if something goes wrong, all you need is a doctor, not overpriced treatment.

bee stings

To defend Paltrow, it needs to be made clear that this nonsense didn’t just happen to her. Bee therapy is recommended as a treatment for a variety of diseases and problems, from sclerosis to inflammation of the joints.

Really, don’t get stung by a bee. It doesn’t help and it hurts.

There is not a single solid study that shows that the direct use of bee venom in the human body has any benefit, despite the fact that some of its ingredients are used in the cosmetic industry.

And instead, again, there are many dangers to this practice. Firstly, it is very painful, and later allergy sufferers go into anaphylactic shock and can seriously endanger their lives if they allow bees to sting them. I mean, don’t do it.

colon cleanse

Paltrow has recommended through her website on several occasions to undergo a colon cleansing procedure, which consists of introducing a hose and supposedly dozens of removing toxins that remain attached to the intestinal walls.

Do not connect a hose to the rectum, there is no scientific basis for this, the digestive system is fully prepared to eliminate all waste, and it is dangerous to perform these steps and can cause punctures and tears. There is.

Raw goat milk detox diet

In an interview published on Goop, the “Natural Therapist” promoted a detox diet based on consuming only raw goat’s milk for several days. As he said, this treatment dates back to the “biblical era”

We have already mentioned it, but here again: the body does not need detox treatment, the body knows how to purify itself. Drinking raw milk, on the other hand, is not a good idea, cold sterilization and sterilization processes have been created to eliminate the very dangerous bacteria that are present in raw milk. Seriously, take advantage of this advancement in science and technology and take unnecessary risks. Please no.

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.

If you don’t already know Fitenium is a free, mobile, video-based social network for athletes who train strength or bodyweight exercises. At Fitenium users can follow their performance, compete and get discounts in nutrition and sports equipment stores. Download it here.

Yam is a rare tuber on our table, but today we will talk about it because it can mean another source of high-quality carbohydrates and other beneficial nutrients. However, the yam, which is very common in the Caribbean and South America, has been part of their diets for centuries. It is a food suitable for diabetics and paleo, so you are interested in knowing the yam properties!

what is name

Like other root vegetables such as sweet potatoes, potatoes and cassava, yams are rich in carbohydrates, mainly containing more than 70% starch and more than 8 grams of fiber per 100 grams of food. Slows down digestion and lowers blood sugar.

Similarly, it is a tuber that is richer in protein than any other and contains approximately 12% of this nutrient.

Rich in high-quality micronutrients, among which calcium, vitamin C, phosphorus and potassium stand out, certain antioxidants also help the body’s health.

Regarding their physical properties, yam starch and flour are stable in hot suspensions and have gelling and thickening properties.

HOW TO COOK THE YAM

Being rich in fiber and vegetable protein since it is a concentrated carbohydrate, it is considered an energy food (so you go to the gym to give it your all), but it does not have a high glycemic index, so it is not only for athletes but also for patients diabetics.

In addition, it provides a feeling of satiety, which, together with its high percentage of starch and its low cost, make it a self-sufficient crop according to the FAO.

Rich in fiber, resistant starch, and antioxidants, it has elevated blood triglyceride levels and diseases caused by lipid oxidation, including atherosclerosis, even in rodent studies. In addition, it can be used to extract gluten-free flour and starch. This is ideal for diversifying the diet of celiac people.

For example, the stewed yam is a simple recipe that everyone can prepare, you will not need many ingredients and it will be ready in a matter of minutes. Accompany a delicious fish with this stew or eat accompanied by pieces of bread or tortillas. Best of all, you can buy this root vegetable at any supermarket or even grow it in your own home.

However, it is also very adaptable for recipes such as making chips, soups or even stews, it is incredible!

How to use yam in cooking

Yam is an inaccessible crop, but you should keep in mind that its use in the kitchen is very similar to that of other tubers. Always cooked, boiled and then baked or grilled, just like flour or starch.

You can take it in the form of flour or starch, which acts as a thickener or gelling agent to replace, for example, corn starch, and it can also be fermented to make bread suitable for celiacs.

Of course, you can also use it to cook other types of dishes, such as stews, soups and chips, to eat between meals.

It is a high-quality, low-cost food product with excellent properties that ensure its quality throughout the food industry. And not only that, but in cosmetics the yam root cream improves the condition of the skin in general (it is known as the plant of youth) giving it vitality, and applied in the form of circular massages is another way to strengthen and give volume to the breasts. Also massages with yam root cream are a very effective stimulant and an excellent sexual energizer.