There is something to be said for the time you take between each set of repetitions. In order to function at near full capacity a muscle needs to rest 2-4 minutes. After a set of repetitions the muscles supply of adenosine triphosphate or ATP and phosphocreatine or PC will be depleted. It takes about 2 minutes for this to be replenished. This is your muscles’ energy for contraction. So make sure you are getting plenty of rest between sets!!!!!!