Types of force and their errors
Usually in sports training jargon it is considered that “there are many types of strength”, and each of them is given a name. This post analyzes some of them and their associated errors.
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.
Clarifications on some common terms
When talking about force, it is only possible to refer to a value of applied force or “peak” of force, expressed in newtons, and the relationship between any value or “peak” of force that is applied and the time it takes to apply it. (RFD (rate of force development), expressed in N*s-1)
Therefore, all you will have is a peak or force value and an RFD. The “peak force” can refer to the force applied in a static action, but also, and especially, to the value of applied force that is reached before each load that moves. However, in the jargon of sports training it is considered that “there are many types of strength”, and each of them is given a name. Some of these names make some sense, although they do not add anything to the concepts already exposed, but in other cases they are inappropriate. Some of them are now discussed.
Maximum strength
This term is as common as it is misused. It is exclusively associated with the value of the RM or the Maximum Isometric Force (FIM). This statement is a serious mistake because, whether we like it or not, all the training we do is necessarily “maximum strength”. This is so because from the point of view of physical performance, which in some cases coincides with the specific performance, the only effect that can be expected from training is to improve the value before an absolute load, whatever it may be, from the The lightest to the highest, or from those gestures, specific or not, that are performed at very high speed to those that are performed before more or less heavy external loads, and these changes (improvements) can only occur if the “maximum strength” improves. ” applied between said charges.
Displaced loads could be, for example: one’s own body weight, a bicycle at high or low cadence, rowing a boat, throwing a handball, hitting a badminton shuttlecock, throwing a seven kilogram weight, lifting any weight of training at the maximum speed possible…
Error: “we are going to train the speed not the maximum strength”. This is simply impossible. Because it is not possible to improve the travel speed of any load if the “maximum force” applied to said load does not improve.
Error: “we are going to perform a power training…” When this statement is made, it is implied that if there is a “power training”, it must be different from a “strength” or “maximum strength” training or any other. Well, again, we have to say that this is impossible, because you cannot improve speed at the same absolute load if you do not improve the maximum force applied to it and, if you do not improve speed, you cannot improve power: do the same job in less time.
That is to say, it can only improve the power in a specific action, if it improves the maximum force or the corresponding load. Therefore, not only is it wrong to make this statement, but power training itself does not exist, because all training is for power”, … if maximum strength improves under any load. Therefore, the only possible training is “training for maximal strength improvement”.
Explosive force
The term “explosive force” is widely used in training jargon and for this reason we have considered clarifying the meaning of this expression and sport in general could be moderately justified by two meanings of the definition of this term in the RAE dictionary as are “sudden release of energy…” and “rapid development of something” The adactation of the meaning “sudden release of energy…” can be associated with the rapid release of energy necessary for muscle activation and reaching a high or maximum muscular tension in the unit of time, both in static and dynamic actions. This rapid release of energy would also be responsible for the “breakthrough development…of force” in a muscular action.
But our definitive reflection about this term is that it would be healthy not to use it in a wrong way, since it is associated with high-speed actions and as opposed to static actions and those carried out with medium and high loads, ignoring that if the term is used “Explosive should be applied to all muscular actions or activations in which force is tried to be applied as quickly as possible, that is. reach the maximum production of force in the unit of time (maximum RFD) before any load and activity, including static actions.
elastic-explosive strength
When this term is used, it refers to the result of an action in which the subject performs an intense or high-velocity stretch-shortening cycle (CEA). It is understood that the result of the action depends in part on the elastic force that has been generated in the eccentric phase of the CEA. The term “explosive” is used (or should be understood as such) because the concentric phase of the action is performed at the maximum speed possible for the subject. Although this term could be admissible, adding “explosive” does not make sense, because the “elastic” force would not be used if the concentric phase were not performed at high speed and immediately after the eccentric.
In any case, the only thing that we could measure in both the eccentric and concentric phases would be a force peak, or multiples, and a time to reach each of these peaks, that is, one or multiple RFD values. These “peaks” and their corresponding RFD values would be the indicators * of the result of the action, and, therefore, the performance in height, horizontal distance or speed reached after the action will depend on them. That is, the “elastic” force has its own entity, and it is not necessary to add the term “explosive” for it to exist as such, although the concentric action must be “explosive” so that it can be used. For this reason, in the field of training and strength evaluation, it would be sufficient to use “elastic” to indicate a training objective and to evaluate performance in this capacity.
Reflex-elastic-explosive strength
This term is similar to the previous one, but it is meant to imply that the CEA is performed at the highest speed and that the stretch reflex contributes to making the concentric phase more effective. This situation would occur to a greater extent when the CEA occurs after “a fall” to the ground from a certain height. That is, it would refer to an action with “bounce . Although the effect of the action could depend in part on the contribution of the stretch reflex and the elastic force generated, and this would justify the use of this term, what we could measure and the performance indicators would still again be the peaks of generated force and their corresponding RFD values. Sometimes, to refer to this type of action, the term “reactive force” is used. When using this term, it should be understood that after a type of action, in this case an eccentric action, there is “a reaction”, that is, an action in the opposite direction, which in this case will be a concentric action. The opportunity to exclude the term “explosive” would have the same justification indicated in the previous case.
ballistic force
The term “ballistic” refers to “throw / throw” and the trajectory of the projectiles, so its use in training jargon would not be justified, unless it was used to study the trajectory of launches in any sports specialty in which this type of action occurs. However, in training jargon this expression is used to refer to actions that are carried out at high or maximum speed and when jumping and throwing objects or external loads.
However, in many of the occasions in which this term appears in the international literature (Desmedt and Godaux, 1977, Behm and Sale, 1993, Van Cutsem et al., 1998, Aagaard et al, 2002, Aagaard, 2003, van Cutsem and Duchateau, 2005, ), the “ballistic” action also refers to the isometric action in which it is tried to apply the force as quickly as possible, that is, static action in which it is tried to reach the maximum RFD. According to this definition, one speaks of “ballistic training or ballistic action of isometric force” that is to say, in the absence of displacement and, therefore, in the absence of speed and the release of any charge.
Therefore, its “ballistic” character is determined by the slope of the force-time curve. In other words, a “ballistic” action would be one in which the force is applied as quickly as possible, trying to reach the maximum slope or maximum RFD, but without the need for displacement. For this reason, the “ballistic force” would originally refer to the RFD (RFDmax) in static actions, although it could also apply to dynamic actions in which it is also a question of reaching the maximum RFD before the charge in question. This would mean that, if the action is dynamic, the speed would be maximum under any load, but this type of action should be defined as “ballistic force” not because the action is performed at high speed, but because of the requirement of that, to reach maximum speed under any load, the RFD must be maximum.
It is important to distinguish between “ballistic contraction” (perhaps better “ballistic activation”), characterized by the attempt to reach the maximum RFD in muscle activation, but in which the velocity may or may not be zero, and “ballistic movement”, characterized by reaching “high speed” and in some cases jumping or throwing an object, all of which depend on a high or maximum RFD, although of course if what determines the action to be “ballistic” is trying to hit the maximum RFD, movements with intermediate or high charges, moving at medium or low speeds, are also “ballistic actions”.
Therefore, all these types of actions would be precisely and unambiguously defined if it is indicated that strength is trained or performance is measured by moving the load at the maximum possible speed. If the training or the measurement has to be static / isometric, the indication would be to activate or apply the force as quickly as possible (reaching the maximum RFD). In our case we do not use and will not use the term “ballistic” to refer to any type of force or training. When proposing a workout, if necessary, due to the characteristics of the exercise, it will be indicated that the action or exercise must be carried out at the maximum possible speed, whether it is jumping or whether the load is thrown or not, without going into qualifiers about the execution type.
quick force
This term is widely used in sports training jargon. It is related to those actions in which the displacement speed is high or very high. The first problem we encounter is that it is not clear where the “fast” force ends and the “slow force” begins. That is, what range of percentages, normally 1RM, and considers that it corresponds to the “fast force” and which to the “slow force”.
The second and most important of the problems is that the concept of “fast strength” is associated with speed of movement, or speed of muscle shortening, in the best of cases. But it would seem more reasonable that “quick force” should be associated with the “speed” with which the force is applied. If the speed in the application of the force were high, the force could properly be called “fast”, although we would always have the problem of determining from what degree of speed it is considered as such.
Although the reality, and the paradox, is that when light or very light loads are moved (less than 30-40% of the RM or approximately 30% of the FIM), that is, when loads are moved at high speeds, the force is applied more slowly, because the slopes of the CFT that are achieved with these loads, that is, the RFDmaxs, are less than when the loads are medium or high, and this means that the force is applied more slowly: less force applied in the same time, that is, lower RFD. Therefore, high speed of muscle shortening (high speed of movement) should not be identified with maximum RFD, since the RFD that is reached with light loads is less than the maximum, although it is the maximum possible for the load that is being applied. displaces. Therefore, the term “fast force” is confusing, because it does not define where it starts and where it ends, but, especially, it is inappropriate, because what is considered “fast force” is really “slow force”, since the “speed ” with which the force is applied with light loads is less than with medium or high loads. That is, the “rapid force” associated with a lower production of force in the unit of time.
Therefore, in the same time less force is applied, that is, the force is slower, or it takes more time to reach the same value of applied force, which means that the force is applied “less quickly”. In short, the term “rapid force” can cause confusion, unless it is associated with the production of force in unit time (RFD), which is the only thing that would give it meaning. Therefore, it is preferable to stop using the term and always refer to the RFD under different loads or at different times of force application.
The misuse of this term sometimes leads to training goals that do not make sense. For example, it is not uncommon to hear that we are going to train the “explosive force” first and then the “rapid force”. This approach is really indicating that neither of the two concepts is properly applied. The “explosive force”, which, as indicated in previous paragraphs, must be understood as RFD, is trained with any load and at any time, provided that the subject tries in each action to apply the force as quickly as possible for him, and therefore, you can use any load to train, including those often associated with “quick strength”.
This means that there is no “explosive force” and “rapid force” phase in a training cycle, but “RFD training” is the only correct expression and the only possible training objective. The load that is used at each moment is at the discretion of the person responsible for the training programming, but the RFD will always be training, with high, medium or low loads. Therefore, the term “rapid force” should not be used and “explosive force” is much better expressed if it is replaced by RFD.
Explosive power (explosive power)
This term is not widely used in Spanish, but it is in the international literature. It is understood that it refers to the maximum power that is reached before a specific load or action in any movement. This term is not appropriate because the maximum power can only be reached if the charge under analysis or measurement moves at the maximum possible speed, and this maximum speed is the expression or consequence of “explosiveness”. That is to say, the maximum power is not given to any load if the action is not carried out at the maximum possible speed, or what is the same, applying the force as quickly as possible or reaching the maximum RFD (“explosivity”) before the load. moving load.
Therefore, there can be no “maximum non-explosive power”. Non-maximum power values could be reached before a specific load if it moves at non-maximum speeds (without “explosiveness”), but this is of no interest from any point of view. Therefore, this term can only lead to confusion, without contributing anything to knowledge or training methodology.
force-speed
This term is rather unfortunate, since one noun (speed) cannot be considered to qualify another noun (force). Therefore “force-speed” is not any type or class of force. On the other hand, if this expression were not used as a type of strength, but to indicate that “strength-speed” training is being done, that is, that it is intended to do training to improve strength and strength simultaneously or simultaneously speed, would make even less sense, since it is not possible to improve speed without improving strength.
In order to reach a higher speed before the same load, it is necessary to apply more force to said load, that is, it is necessary to improve the “maximum force” for that load. It must not be forgotten that a subject has as many values of maximum force as loads it has to move.
Resistance force
This term is also equally unfortunate, and for the same reason as in the previous case, since a noun (resistance) cannot be considered to qualify another noun (force). Therefore “force-resistance” is not any type or class of force. Sometimes this expression is replaced by “resistance to force” (it would be more appropriate to use the term “resistance to the loss of force”, since what is intended is “to oppose the loss of force, not the force itself) , considering it as equivalent. This complicates things even more, since resistance to loss of strength is not only not any type of strength, but is a totally different concept. “Resistance to loss of strength” indicates the ability of the subject to maintain a given value (peak) of force and RFD over time. When these two values go down, speed is lost and performance decreases.
On the other hand, if this expression were used to indicate that “strength-resistance” training is being done, that is, that it is intended to! Training to improve strength simultaneously or simultaneously would make even less sense, since it is not possible to improve resistance to a given load without improving the force applied to that load. That is, the resistance can only be improved if the effort required to move a load once decreases with respect to the effort previously required, and this can only be achieved if the force that can be applied to said load increases.
Naturally, other terms close to these and widely used such as “speed resistance”, “fast force resistance”, “speed-resistance”, “speed-resistance”… and other similar ones have no justification, since, For example, “speed drag” (or stall resistance) is the same as “force stall drag” since speed will drop if the applied force decreases. And the same can be applied to the rest of the expressions. Therefore, the only appropriate terminology and the only objective that we can set ourselves in this sense is to improve the “resistance to loss of strength”. If this happens, performance will improve, because a higher average speed (or more power, depending on how performance is measured) will be achieved under the same load for the same (regulatory) time or for the same regulatory distance. In this last case, ell: me decreases for the same distance, which is what is intended, because it means a higher performance.
