The foam rolling of quadriceps decrease the kinematics of step during a 30-m sprint run

The objective of this study was to investigate the effects of foam rolling of the hamstrings or quadriceps muscle groups on the step kinematics during a30-m sprint run.Moderately active physical education male students (n =23, 21.4 ± 0.7 years, 79.2 ± 8.3 kg, 1.80 ± 0.06 m) participated in this study. The Optojump Next with the Witty timing system were used to measure the kinematics of sprint running (contact time, step length, flight time, step velocity). Each subject completed two maximal 30-m sprints after the warm-upunder three conditions: foam rolling of quadriceps, foam rolling of hamstrings, and dynamic stretching. The main results of this study showed that the foam rolling of quadriceps decreased velocity of step, step length and flight time as well as increased contact time during sprint immediately after warm-up (2 min) compared to warm-up with foam rolling of hamstrings. There were not significant differences between the three warm-up conditions during the second run (after 8 min passive break). The results suggest that practitioners should avoid the foam rolling of quadriceps exclusively in terms of performance a 30-m maximal sprint. It should also pay more attention to apply the optimal volume of quadriceps to hamstrings foam rolling during the warm-up procedures.