Ensuring optimal range of motion and muscle stiffness represents an important factor for preventing the occurrence of sport-related injuries or injuries of the muscle-tendon unit. One of the methods that have been shown to improve flexibility is foam rolling, which has gained popularity in the past few years. Foam rolling is widely used by recreational athletes, therapists and professional athletes as a method for flexibility training and is increasingly more investigated by researchers, who have attributed numerous positive effects to it. In the literature, a number of acute and chronic effects of self-massage with a foam roller have been explored, but mechanisms that pertaining to reduction in stiffness and thus a potential reduction in injuries and increased mobility are largely unknown.
The purpose of this study was to investigate and compare acute effects of 2 x 60 seconds of foam rolling and 3 x 30 seconds of dynamic stretching on flexibility and passive muscle stiffness of the hamstrings.
18 individuals participated in this study (13 men and 5 women). All subjects were healthy and had no lower extremity injury during this study. A repeated measures design with randomised order of interventions was employed, which were carried out in 2 sessions, with a minimum of 48 hours between sessions. Measurements of range of motion of the knee, knee angle and torque, were assessed with the help of an isokinetic dynamometer after warm-up, 10 minutes after warm-up, immediately after sham intervention or immediately before intervention, immediately after intervention, 15 minutes after intervention and 30 minutes after intervention.
Results of this study show a significant increase in range of motion after both interventions immediately after intervention, compared to the measurements after warm-up and immediately before intervention. There were no significant differences between interventions. Results showed no significant changes in passive muscle stiffness of the hamstrings by any intervention.
The results of this study show, that both foam rolling and dynamic stretching are equally effective in acutely increasing range of motion without any significant effects on passive muscle stiffness of the hamstrings.