The immediate effects of foam rolling of the hamstrings muscle group on the contractile properties of the knee muscles in football players.

Excessive amounts of intense training, without adequate recovery time, can overload the musculoskeletal, immune, and metabolic systems, resulting in a potentially negative effects on later exercise performance. During the competitive period, the ability to recover after intense training and competition is an important factor of success in soccer. The purpose of this study was to determine the effect of hamstring foam rolling on the knee muscle contractile properties in soccer players, after a sports-specific load. 20 male professional soccer players were included and contractile properties of the biceps femoris, rectus femoris, vastus medialis and vastus lateralis muscles were measured with tensiomyography, before and after a Yo-Yo interval test and after 5 × 45 s of hamstring foam rolling. Additionally, active and passive knee extensibility before and after the intervention were measured. A mixed linear model was performed to determine the differences between the mean values of the groups. The experimental group performed foam rolling, while the control was resting. Five repetitions of 45 s of hamstring foam rolling had no statistically significant effect (p > 0.05) on any of the measured muscles following the Yo-Yo interval test or foam rolling intervention. There were no statistically significant differences in delay time, contraction time and maximum muscle amplitude between groups. Active and passive knee extensibility did not differ between groups. It seems that foam rolling does not affect mechanical properties of the knee muscles or hamstring extensibility in soccer players, after a sports-specific load. • Foam rolling does not affect muscle contractility. • A researchers' dilemma is what to do about the clinical practices that are widely accepted without scientific basis. • Foam rolling does not affect hamstring extensibility in soccer players, after a sports-specific load. [ABSTRACT FROM AUTHOR]