Acute neuromuscular and fatigue responses to the rest-pause method

Objectives: To compare muscle recruitment, maximal force, and rate of force development changes following different resistance exercise protocols with a constant volume-load. Design: Within-subjects randomized crossover trial. Methods: Fourteen (n=14) resistance trained male participants completed three different resistance exercise protocols involving 20 squat repetitions, prescribed at 80% of 1-repetition-maximum. Protocol A consisted of 5 sets of 4 repetitions with 3. min inter-set rest intervals, protocol B was 5 sets of 4 repetitions with 20. s inter-set rest intervals, and the rest-pause method was an initial set to failure with subsequent sets performed with a 20. s inter-set rest interval. Maximal squat isometric force output and rate of force development (RFD) were measured before, immediately upon completion (IP), and 5. min (5P) following each protocol. Muscle activity from 6 different thigh and hip muscles was measured with surface electromyography (EMG) at each time point, and during every squat repetition. Results: Participants completed the rest-pause method in 2.1 ± 0.4 sets, with a total protocol duration of 103. s compared to 140. s and 780. s for protocols B and A, respectively. All protocols elicited similar decreases (p< 0.05) in maximal force and RFD at IP, with full recovery at 5P. Increased motor unit recruitment was observed during the rest-pause method compared to both protocols A and B for all muscles measured (p< 0.05). Conclusions: As a result of the increased EMG during exercise and no greater post-exercise fatigue, it was concluded that the rest-pause method may be an efficacious training method for resistance-trained individuals.