Immediate effects and one-week follow-up after neuromuscular electric stimulation alone or combined with stretching on hamstrings extensibility in healthy football players with hamstring shortening.

OBJECTIVE: To assess the immediate and mid-term (after 7 days) effects of electric current combined with simultaneous muscle stretching (EME technique) per comparison to the isolated use of the same current (without applying simultaneous muscle stretching), over the hamstring extensibility in football players with hamstring shortening, and to estimate the clinical benefit of the interventions according to the muscular extensibility.

METHODS: Forty-eight participants were randomized to receive one session of EME technique (n = 26) or one session of the electrical current (EC) alone (n = 22). The measurement of the hamstrings extensibility through the active knee test was carried out before and immediately after each intervention and one week later.

RESULTS: A significant interaction group x time was observed (F2,84 = 7.112, p = 0.001; partial eta squared = 0.145). The hamstrings extensibility changed significantly immediately after the EME technique (147.3° ± 16.4° to 153.5° ± 14.2°, p < 0.05), but not after the EC only (144.2 ± 10.2° to 141.7 ± 7.8°, p > 0.05). One week after the intervention no significant differences were found to the baseline values in both groups. The number needed to treat to prevent one new case of hamstring shortening was 3.

CONCLUSION: The combination of electric current with simultaneous stretching is an effective technique to acutely increase the hamstring extensibility of football players with hamstring shortness.