It’s no secret: training to failure is the special sauce that makes muscles grow. As anyone who’s studied basic exercise physiology can tell you, the body isn’t going to adapt unless it is challenged to do so. This point is not up for discussion or debate.
What is debatable and entirely subjective is the definition of “training to failure”. When is a set of push-ups complete? Is it when you’re face down on the floor, arms quivering, completed gassed and swimming in your own spit and sweat? Or is it a few reps before that?
Personally, I see “failure” as the breakdown of technique. I don’t like seeing people grind out ugly reps for the sake of chasing failure. I guarantee those last reps are garbage. All the body learns from that approach is how to adopt compensatory motor patterns; i.e., you learn how to move poorly.
It’s like lifting legend Tommy Kono said: ”practice makes permanent.” I tell all of my clients to keep a rep or two in the tank for this very reason. As long as they’re working with enough intensity to challenge themselves, that’s what’s most important.
So what happens if you reach the end of a prescribed rep range and find you’re not sufficiently challenged? Treat that set as a warm-up, add some weight and start over. Or, if calisthenics are your jam, progress the movement to a more challenging variation (e.g., move from a split squat to a skater squat, a pike push-up to a handstand push-up). Just remember, don’t increase the challenge too much. You need to accumulate a sufficient number of reps when training to failure, otherwise you won’t trigger the necessary adaptations. A decent rule of thumb: if you can’t do at least five reps, the exercise is too challenging.
Working hard is essential. Pushing sets past the point of productivity is not. As soon as reps start to slow to a grind, give yourself one or two more and that’s that. Work hard, but stay fresh. It’s a delicate balance, but therein lies the art of training.