The muscles in our bodies enable us to complete a movement by pulling on our bones. This movement requires an impulse or task from the brain to the muscles. The amount of muscle fibers used to complete a movement is dictated by the resistance or task. In different terms, we don´t run on 100% of the capacity of our muscles all the time. Actually, we run movements below 100% more often then we do on our maximum capacities
i.e. when you pick up a bottle you don´t use all the muscle fibers inside a muscle or else the body would use all of its capabilities to complete a movement every time.
So the body has a specific order in which it uses the number of muscle fibers required to complete a movement, this is referred to as ´rate coding´. Now comes the important piece of the puzzle.
The efficiency of the neuromuscular system correlates a lot with the number of motor units you are able to turn on. How well the nerves and muscles are able to collaborate dictates the possibility of performing at the maximum capabilities of the skeletal muscle.
Let´s put this in a more familiar model, one individual is able to perform a back squat at 300 pounds. If he puts more weight on the bar he is not able to stand back up again. His buddy also does 300 pounds as a maximum and when increasing weight he is also not able to stand back up again. We refer to these to people as subject A and subject B.
When subject A performs the back squat at his maximum we refer to this as his 100%. If we grab 85% of this weight he is able to perform just about 3 reps with it.
When subject B performs the back squat at his maximum also his 100%, grabs 85% but he is able to complete 7 reps with this weight.
Who is the one with a less efficient neuromuscular system?
WRITE DOWN ON A PIECE OF PAPER
Just kidding...read on it wasn't really a question.
Subject B is the one with a less efficient neuromuscular system because in comparison to subject A who doesn´t have any ´reserves´ subject B was able to squeeze out a lot of reps while being close to his so-called ´maximum capacity´. So knowing that he is able to do so much work close to his max the questions immediately should be, is the 100% even a realistic number? Wouldn´t he be able to get a much higher 100% if he just focuses on creating a more efficient collaboration between the nerves and the muscles? (again these are not really questions of course)
So the moral of the story is, if a person is truly able to express his or her maximum capabilities in strength (or power/speed) he or she should need time to recover when you consider the ATP-CP system to work to its fullest. But when an individual is not able to express it effectively, he or she will not need that much time to rest. You´ll see this often times during regular gym classes when a beginner does a set, rests for one minute, and immediately jumps back for another set whereas an advanced client needs way more time to be able to repeat the same effort. The main focus of the beginner should be to increase the ability to express strength (or power/speed). This means that he or she should identify where limitations occur and fix them. Limitations like: mobility, stability, imbalances, coordination, and more. Improvements will ideally bring the 1 rep max higher while creating a more realistic 85% max effort.