Static Stretch And Warm-up

Abstract

Stretching is generally recommended to prevent injury and to improve individual's performance. Many authors have demonstrated the thermal agents benefits on the flexibility enhancement. For instance, Williford et al. (1986) proposed stretching alone, i.e. without warm-up, for a better flexibility improvement. However, such stretching modality may be moot for some athletes due to the high stress on the musculoskeletal system. Therefore, warm-up followed by a short rest period prior to stretching seems to be more appropriate. PURPOSE Thus, we investigated the effects of a 5-weeks static stretch program following a warm-up interspersed or not with a 20-minutes rest period. The training-induced effects were examined on the lower-limb flexibility and vertical jumping ability. METHODS Ten physical education students volunteered to participate in this study. Five of them conducted the static stretches of the lower-limb immediately after 10 minutes warm-up (jogging). The remaining five performed the same stretching training after a 20-minutes rest period following the warm-up. Static stretch sessions consisted of four bilateral 30-second passive stretches of the quadriceps femoris, hamstring, adductor and calf muscles, conducted two times a week for five weeks. flexibility (i.e., range of motion) of the hamstring, adductor and calf muscles was measured before and after the stretch training using goniometry. Moreover, the explosive strength was assessed using vertical jump tests (squat jump and counter movement jump). Stretch effects were then analyzed using a two-way analysis of variance with repeated measures. RESULTS While no significant improvement was recorded for the vertical jump performance and the calf and adductor muscles flexibility, our results indicate a significant hamstring flexibility increase (P <0.05) after the 5-weeks period. Indeed, the right leg to hip angle (supine subject), exhibited 14.6 ± 6.2° and 11.0 ± 6.0° mean (± S.D.) increases respectively for the group with and without the resting period between warm-up and stretching. Nevertheless, these flexibility improvements were not different between groups. CONCLUSIONS Our results reveal that a 5-weeks stretch program is sufficient to improve the hamstring flexibility but not for calf and adductor muscles. Increasing either or both training duration and session number per week seems required to obtain a flexibility increase for these two muscle groups. Performing stretches after a rest period or immediately after the warm-up does not appear to significantly modify the effectiveness of static stretching. Finally, stretching does not improve jump height.