Acute effects of different stretching exercises on muscular endurance

This study aims to evaluate the acute effects of different stretching exercises on muscular endurance in men, in terms of the number of sets, set duration, and type of stretching. Two experiments were conducted; in the first one (E1), the subjects (n = 19) were evaluated to test the effect on the number of sets, and, in the second one (E2), the subjects (n = 15) were tested for the effect of set duration and type of stretching. After a warm-up of 10-15 repetitions of a bench press (BP) with submaximal effort, a one-repetition maximum (1RM) test was applied. For E1, BP endurance was evaluated after static stretching comprising one set of 20 seconds (1 x 20), two sets of 20 seconds (2 x 20), and three sets of 20 seconds (3 x 20). For E2, BP endurance was evaluated after static stretching comprising one set of 20 seconds (1 x 20), one set of 40 seconds (1 x 40), and proprioceptive neuromuscular facilitation (PNF) stretching. All tests were performed 48-72 hours apart, at which time the muscular endurance was assessed through the maximal number of repetitions (NR) of BP at 85% of 1RM until fatigue. The NR and the overload volume (OV) were compared among tests through repeated-measures analysis of variance. No significant effect of the number of sets on muscular endurance was observed because no statistically significant difference was found when comparing all stretching exercises of E1 in terms of NS (p = 0.5377) and OV (p = 0.5723). However, significant reductions were obtained in the set duration and PNF on NR (p < 0.0001) and OV (p < 0.0001), as observed in E2. The results suggest that a stretching protocol can influence BP endurance, whereas a decrease in endurance is suggested to be attributable to set duration and PNF. On the other hand, a low volume of static stretching does not seem to have a significant effect on muscular endurance.