Acute effects of static and proprioceptive neuromuscular facilitation stretching on sprint performance in male swimmers

Aim. This study verified the acute effect of static stretching (SS) and proprioceptive neuromuscular facilitation (PNF) stretching on front crawl swimming performance. Methods. Thirteen young males (22.7 +/- 1.42 years; 77.2 +/- 7.25 kg; 172.5 +/- 1.33 cm; BMI, 25.9 +/- 4.09) were submitted to three randomly select experimental protocols as follows: a) 50 m front crawl swimming maximal sprint test without any stretching training (CTRL); b) 50 m front crawl swimming maximal sprint test preceded by SS (2 sets of 30 s) for pectoral and quadriceps muscles (SS); and c) 50 m front crawl swimming maximal sprint test preceded by PNF (2 sets of 30 s using the Scientific Stretching for Sports [3S] method) for pectoral and quadriceps muscles (FNP). A one-way ANOVA with repeated measures was performed to identify differences between groups. Results. When the effects of control versus the stretching protocols were compared, a significant decrease was observed in the 50 m sprint test times: CTRL: 32.12 +/- 2.92 s vs. SS: 32.92 +/- 2.51 s, P<0.05; and CTRL: 32.12 +/- 2.92 s vs. PNF: 33.52 +/- 3.07 s, P<0.0001. We did not find any difference in performance when we compared the stretching protocols (P>0.05). This study is the first to demonstrate a loss in swimming performance following muscle stretching exercises. Our results demonstrated that SS and PNF caused statistically significant deleterious effects on swimming performance as evaluated by time taken to complete a 50 m front crawl swimming test. Moreover, SS did not generate a significantly different response compared to PNF. Conclusion. This study shows that acute SS and PNF cause deficits in front crawl performance.