Athletes like baseball pitchers, sprinters, 50-m freestyle swimmers, martial artists, wrestlers, fencers, tennis players and so on must produce powerful movements and repeat them several times with little or no rest. In order to maintain the same amount of power with each effort, a certain level of power endurance is required.
Power endurance is typically characterized by intense, repeated efforts for a relatively short period of time (less than 30 seconds) (1). A tennis player for example, has to produce several powerful shots in quick succession during a rally that may only last 10 seconds. A 100-m sprinter may take 48-54 powerful strides over a 10-12 second race and their success depends, in part, on maintaining a high power output in the last 20 meters.
Once maximal strength has been developed (earlier on in the annual strength program) it can be converted into explosive power through various methods of power training. Now power endurance training can be used to train the fast twitch fibres to resist fatgiue allowing explosive power to be maintained for longer.
Power endurance training uses moderate loads of 50-70% 1RM lifted for 15 to 30 repetitions. Because this can lead to a significant build up of lactic acid, rest periods between sets are long (5-7 minutes) and a minimum number of sport-specific exercises are used (about 3-4). Exercises are also completed in a circuit training format i.e. one set of one exercise is completed, then one set of the next exercise and so on. Alternating exercises allows maximum recovery and sufficient time for lactic acid to disperse.
This is a critical rule to follow. If rest intervals are too short and sets are completed while the athlete is fatigued the result will be hypertrophy (increase muscle mass) rather than power endurance. Sets should not be completed to failure but should end when repetitions are no longer powerful and rhythmic.