A single session with a roller massager improves hamstring flexibility in healthy athletes: a randomized placebo-controlled crossover study

Purpose The aim of this randomized placebo-controlled crossover study was to compare the acute effect on young athletes of a single session of roller massager (RM) with that obtained from passive static stretching (PSS) and a placebo intervention (PL) on hamstring flexibility and on strength. Methods Twenty-nine (23 male, 6 female) young athletes completed the study. Maximal voluntary contraction (MVC) and two-leg sit-and-reach test were performed before and immediately after PL, PSS and RM on three different days. Results Results showed that all three interventions increased the flexibility of the hamstring muscles compared to the pre-test measurements (Wilcoxon signed-rank test, p < 0.05). Only the RM intervention was significantly higher than the PL intervention (sham ultrasound). Stretching intervention was not significantly different from either of the other two interventions. None of the three interventions significantly changed the muscle strength in the short term. Conclusions RM can be considered as an effective alternative to stretching to increase the flexibility of the hamstring. This could be meaningful when stretching is contraindicated or evokes pain.