TRAINING TO FAILURE FOR STRENGTH AND MUSCLE GAINS
First off, let me clear out that failure is not just when you can no longer perform any more reps, there are different kinds of failure, and I like to classify them like this: - Tempo failure: When the rep speed decreases, this the first symptom of fatigue.
-Tolerance failure: This is the typical "burn" sensation of lactic acid building up in your muscles. This appears in hypertrophy training and high intensity intervals, but is not really important to this post. -Technique failure: The form of the exercise starts to break down and other muscles and joints assist in the movement. - Concentric, Eccentric, Isometric failure: When you can no longer perform the concentric/eccentric/isometric portion of the exercise. This can be used simultaneously with the other types of failure, for ex. reaching technique failure in the concentric (for instance not being able to lift the bar off the flor with a straight back on the deadlift). So... when you're learning a new skill, wheather is a new exercise like a Squat for a begginer, or a calisthenic skill such as a Planche, you should stop your set when reaching tempo failure (the earliest sign of fatigue), or even before, depending on the movement.
Because you're body is adapting, training the movement in any form different than the correct technique may lead to improper motor pattern learninig which is very difficult to correct... as we all know, habits are tough to break.
When traininig for strength, you're also teaching your nervous system something new, although not as new as skill learning, you're trying to adapt your central nervous system to be able to recruit as many muscle fibres as possible. Tempo failure is not desirable in a perfect world, but is acceptable when trying to push yourself through high intensities.
Hypertrophy training is more forgiving, bacause the intensity is much lower and the movements are well executed already. In some cases, a little cheat in the last few reps maybe ok to generate more overload on the eccentric to create more muscle damage and metabolic fatigue. Wouldn't recommend it in big compounds though.
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