This kind of training helps muscles to be able to keep performing a movement for a prolonged period of time such as in rowing. Training for muscular endurance involves doing 20 repetitions or more at a controlled speed, generally for one to three sets. It is recommended that short rest periods be used for muscular endurance training, 1-2 minutes between sets of 20 repetitions and even less than a minute if you are doing a more moderate number of repetitions.