## The Character of the physical effort

A definition of effort is the so-called *character of physical effort* (CE), originally presented and explained by González-Badillo, in González-Badillo and Gorostiaga (1993, 1995). **The CE is defined by the relationship between what the subject does and what he could do.** In other words, the relationship between what has been done and what can be done.

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

### Summary

*The character of the effort (CE) is the relationship between what has been done and what is achievable.**The character of the effort is defined by the maximum speed possible in the first repetition and the loss of speed in the series.**What should be programmed in training is not the number of repetitions but the loss of speed in the series.**A light CE would be to perform less than half of the possible repetitions, a medium CE would be to perform around half of the possible repetitions and a high one would be to perform more than half of the possible ones.*

In the so-called “strength training” it would be expressed by the relationship between the number of repetitions that are done in a series (what is done) and those that could be done (what is achievable). If a subject can do 10 repetitions with a weight (absolute intensity) and does 6, we would be facing an EC of 6 out of 10. If we do 3 times that same physical effort, we will have done 3×6(10), that is, 3 series of 6 repetitions with a weight with which we could do 10 in the first series. In this sense, it is important to take into account the difference between load and effort.

To advance in the proper definition of CE, two indicators must be taken into account. On the one hand, the difference between the repetitions performed and those possible or achievable, and on the other, the total number of possible repetitions. For example, if 2(4) is done, the difference between what has been done and what is achievable is the same as if 8(10) is done, but the effect and characteristics of the training are different.

This is so because, although what is “left undone” is the same, 2 repetitions, the number of repetitions that could be done in each case is different, which implies acute effects, and at least in the short term, also different : degree of fatigue, metabolic stress, percentage loss of speed in the series, central and peripheral effects…

**Character of physical effort is defined by two indicators: 1) the maximum possible speed of the first repetition and 2) the loss of speed in the series.**

**In addition, the CE expresses the degree of physical effort in two ways.**

The first occurs when the first repetition of the series is performed before any load (weight). At this time, the CE is defined by the speed of the first repetition, provided that this is performed at the maximum speed possible for the subject. This already defines to a large extent the effect that is expected from the training and the CE that the displaced load supposes, since it allows us to estimate with enough precision the percentage that this load represents from the RM (González-Badillo and Sánchez-Medina, 2010). .

But this is not enough to fully define the CE, since it is easily understandable that the final or total degree of physical effort also depends on the percentage or proportion of repetitions of the maximum possible that is done within the series. It is not the same to do 1 repetition with a load with which you can do 6, than to do 6 repetitions with the same load.

Therefore, since as repetitions are performed at the maximum speed possible in a series with the same load, the speed decreases progressively until the last repetition is reached,** CE is defined by two indicators: 1) the maximum possible speed of the first repetition and 2) the loss of speed in the series.**

The use of the speed of the first repetition and the loss of speed in the series means a great advance in the definition of the concept of “character of the physical effort”. These two indicators allow to reach the maximum precision in the expression of the degree of effort that a training represents when it comes to displacing external loads. But we find the product of both values: **the speed of the first repetition multiplied by the value, percentage, of the loss of speed, we will have the Effort Index, which has been shown to present a high relationship with fatigue, that is, with the degree of physical effort made in the series** (Rodríguez-Rosell et al., 2019)

Continuing with the progress in this knowledge, it has been concluded that we can even do without knowing the number of repetitions that can be done in the series (initial indicator necessary to define the CE). The important thing in this case is to know the loss of velocity in the series, because it has been **observed in laboratory studies that before the same loss of speed in the series, the percentage of repetitions performed with respect to the possible (achievable) is the same before any load between 50 and 70% of the RM**, 2.5% higher for 75%, 5% higher for 80% and 10% higher for 85% (González-Badillo et al., 2017).

This comes to solve the problem that arises from the fact that **Given the same relative intensity (same speed in the first repetition in the series), not all subjects can perform the same number of repetitions. Therefore, the loss of speed in the series equals the efforts, the degree of fatigue generated,** although two people have done a different number of repetitions before the same relative load and the validation of the loss of speed in the series as an indicator of fatigue has been verified in previous studies (Sánchez-Medina and González-Badillo, 2011).

Therefore, **what would best express the degree of physical effort, and what should be programmed, is the speed of the first repetition and the loss of speed in the series, not the number of repetitions to perform in the series before a relative load. Dadaist.** Despite the progress that this load assessment procedure means (physical effort, fatigue…), we will continue to refer to the repetitions performed in the series, because we understand that it will not always be possible to measure speed.

**What would best express the degree of physical effort, and what should be programmed, is the speed of the first repetition and the loss of speed in the series, not the number of repetitions to perform in the series before a given relative load.**

Therefore, the CE is a very useful expression of the load and it comes to overcome the problems that we have detected for the expression of the intensity through the percentages of 1RM and XRM. The systematic observation of the evolution of the difficulty (degree of physical effort) with which the subject moves a load allows us to permanently verify the physical condition of the subject without the need to apply any test. If we can measure the speed, the training load will be quantified very precisely, as we have indicated in the previous paragraph.

If we cannot measure speed, we will have to resort to procedures for estimating the degree of effort that the subject makes. In this case, if we estimate that a subject is capable of performing a certain number of repetitions with a weight (absolute load), and after several sessions we estimate that he is capable of performing more repetitions with said load, the conclusion is that this weight it has become a “physical effort”, a relative, lower intensity, and this is information we need to check the effects of training and to make decisions about whether or not to modify the absolute load.

This is so **because what has to be kept under control is the relative physical effort (relative intensity) that represents the absolute load with which you train.** To achieve this we have to modify the absolute load when appropriate, and to decide if we have to modify it, we must take the execution difficulty as a reference. Thus, by modifying the weight, we do not modify the training, without maintaining the programmed effort: the speed of the first repetition, the CO real percentage of the RM.

As a guide, although without establishing strict limits, since it must always be considered as a continuum, the CE can be considered as light or small, medium, high or very high or maximum. **The CE will be light or small when** the number of repetitions performed in the series is very far from the feasible or possible repetitions.

In terms of speed loss in the set it would mean **that you lose a maximum of about 5-10% of your speed on the first rep.** Therefore, this corresponds to a small loss of speed in the series, and the number of repetitions performed will always be less than half of the possible ones.

**As examples of light or small effort (EC), these values could be considered: from 4-6 repetitions performed, being able to do 16-30 or more.** But, as we have indicated in previous paragraphs, although both examples could be considered as a light CE, their effects are quite different and they would be used in very different situations.

**The CE is considered** as medium when an average number of repetitions is done, which **means a loss of speed in the series close to 20-25%**, and **the number of repetitions in the series is around half of those possible.**. For example, 6-7(12-14), 4-5(8-10).

**The CE can be considered high or very high when more than half of the possible** repetitions are done, **which means a loss of speed somewhat greater than 25-30%**, but 2-4 repetitions are left out in the series. For example: 3(5), 4(7) 5-68), 8(12).

**The CE is considered maximum when the maximum or almost maximum number of repetitions possible within the series is done, the loss of speed is very high (60-70%)** and half of the possible repetitions are clearly exceeded. For example, when doing 9-10(10), 7-8(8) or 3-4(4). In the international literature, this last type of physical effort or type of training (without using the term CE) is called XRM, that is, the maximum possible number of repetitions with a given load, as we have indicated in the previous point.

All this information that we give here in relation to the CE values is indicative, because in our proposal, **if the possibility of measuring speed is available, the number of repetitions is not programmed, but rather the loss of speed at a certain relative load**, which will give rise to the fact that the number of repetitions may be different between subjects for the same degree of physical effort (same degree of fatigue).