Effects of Warm-up on Hamstring Stiffness, Stress-Relaxation, Flexibility and Knee Proprioception in Young Soccer Players.

CONTEXT Nerves or fascia may limit motion in young soccer players, thereby contributing to frequent hamstring injuries. Nerve gliding exercises and self-myofascial release techniques may enhance the range of motion. OBJECTIVE The aim of this study was to compare the acute effect of foam rolling (FR) and neurodynamic nerve gliding (NDNG) on hamstring flexibility, passive stiffness, viscoelasticity and proprioception during the warm-up of soccer players. DESIGN Crossover study design. SETTING Research laboratory. PARTICIPANTS Fifteen male soccer players on the same team (age 18.0 ± 1.4 years, body mass 76.9 ± 7.8 kg, height 183 ± 6 cm). INTERVENTION FR and NDNG included six sets of 45 s with 15 s rest between each set. Over a two-week period subjects performed NDNG and FR on two separate occasions. MAIN OUTCOME MEASURE(S) Hip flexion angle (SLR), knee extension range of motion (ROM), knee joint position sense (AKJPS), hamstring passive resistance torque (PRT), stiffness (STFmax and STF80%) and viscoelasticity (stress-relaxation test (SRT)). RESULTS A significant interaction between time and intervention was found for knee ROM (p = 0.017), PRT (p = 0.044), and STFmax (p = 0.042). NDNG induced an increase in ROM (p = 0.011), PRT (p = 0.008), and STFmax (p = 0.030). Both NDNG and FR induced an increase in SLR (p < 0.001). No interaction or main effects was found for SRT and AKJPS. CONCLUSION The inclusion of NDNG in the warm-up routine increased the ROM more in comparison with FR and may be of benefit to soccer players.