Could static stretching decrease anaerobic power in young soccer players?

BACKGROUND: The aim of this study was to analyze the effect of SS (2x45s) on the anaerobic power (Wingate Anaerobic Test [WAnT]) in young soccer athletes, and to determine if there was a the relationship between SS and anaerobic power output was influenced by subjects' fitness. METHODS: A randomized and crossover study was applied in twenty-one male athletes (16.2 +/- 0.5 years, 65.7 +/- 2.3 kg, 173.3 +/- 1.3 cm). Twenty days before beginning the experimental sessions, a Yo-Yo Intermittent Recovery test 2 (Yo-Yo IR2) was administered. The session experimental (EXP) involved 5 min of warm-up, followed by a SS protocol and then the WAnT. The session control (CON) involved 5 min of warm-up, followed by 5 min of passive rest and then the WAnT. The stretched muscle groups were the quadriceps and hamstrings, which were stretched for 2x45s per muscle group. RESULTS: When clustering subjects by high tertile (HP, N.=7) and low tertile (LP, N.=7) Yo-Yo IR2 results (High and low performance group, respectively), LP displayed a significant impairment after SS for both the peak power (EXP=621.4 +/- 46.6 W, CON= 667.2 +/- 58.3 W; P=0.038; difference of 7.4%) and average power (EXP=481.5 +/- 34.0 W, CON= 502.8 +/- 37.9 W; P=0.018; difference of 4.4%).In contrast, SS did not alter power output in HP peak power (W) P=0.064, average power (W) P=0.239 or minimum power (W) P=0.167. CONCLUSIONS: Therefore, SS can decrease subsequent anaerobic performance in less-fit young soccer players on Yo-Yo IR2.