What is good or not when it comes to reaching muscle failure is always an issue that arises when we want to train with intensity but we are concerned about recovery between workouts. Related to this, the question of how long a repetition should last in time also often arises.
In this article we relate both issues and We explain what you should know about both muscle failure and the duration of a repetition.
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What should we take into account when reaching the failure?
Muscle failure is nothing more than the inability of our muscles to shorten during a concentric contraction. It is a phenomenon that takes place after the execution of several consecutive repetitions that cause an accumulation of fatigue and therefore the inability to continue producing muscle contraction.
Science in recent years has positioned itself on this issue, making several things clear:
- Training to failure can be a great neuromuscular stimulus, especially for advanced people that they need to resort to it to continue progressing. For beginners it would not be so justified although it can take place. If you are a beginner you can surely improve enormously without resorting to failure.
- Training to failure makes more sense for single-joint exercises (bicep curls, for example) and when using low loads typical of moderate to high rep sets. You can reach failure on a squat or deadlift, but it’s not convenient for both the accident risk that entails as for the smaller capacity that we have in these exercises to localize the work in an isolated muscle.
- It is convenient to plan the training taking into account that going to failure can delay not only the recovery between series but also between sessions.
In this way, muscle failure can be used as one more tool in our box but we must take into account what it entails at the recovery level and that if we are beginners, its use is probably not justified, simply for the fact that we can improve without using it.
How long should a repetition be?
We can relate the duration of a repetition to muscle failure in a simple way.
When we begin to perform a series, the speed of execution that we can print in the first repetitions is greater than in the last ones due to a simple matter of accumulated fatigue. Muscle failure will come when the speed of execution is zero and we cannot complete a repetition.
Much has been written about this and even in many didactic or educational guides it has been stipulated that in order to gain muscle mass, “moderate” repetition cadences must be used. In these guidelines, moderate means that the eccentric phase should last between two and four seconds and the concentric phase about two or three.
The least important thing is the duration in seconds or if one guide says three and another says four since in both cases trying to limit this is a conceptual error.
According to the force-velocity relationship, when the speed at which a muscle contracts is reduced due to accumulated fatigue, the force produced and the mechanical stress increase.
In this way, we must extract two things depending on whether we are talking about the eccentric or concentric phase.
- The eccentric phase is the phase in which the muscle stretches and lengthens, like when we squat down. In this phase we simply have to control the weight and it will last a variable time depending on the exercise, the load used and even the person. Typically, it lasts between two and three seconds. Extending this phase further will not result in greater muscle gains.
- The concentric phase is the phase in which the muscle shortens, such as when we squat up. This is where the usual guides are usually obsolete since they try to recommend a limited duration. Nothing further since our intention should be to print as fast as possible regardless of whether it is the first repetition of a series or the last and regardless of whether it looks faster or slower from the outside.
The key is in the concept of intentional top speed. Don’t limit yourself by thinking that the concentric phase should last “x” or “y”, just lift as fast as you can and in a controlled manner. The accumulated fatigue will cause you to be seen lifting slower from the outside, but It will be in these repetitions precisely where you will get the most stimulation.
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