The Immediate Effect of Static Hamstring Stretching on Dynamic Balance and Gait Biomechanical Variables in Athletes With Hamstring Tightness: A Preliminary Study

Abstract

Introduction: Flexibility is an essential component of muscle function, and insufficient muscle flexibility may lead to muscle injuries. Decreased hamstring flexibility is one of the frequently reported risk factors for a hamstring strain and diminished athletic performance. Stretching is a commonly used intervention for increasing muscle length. There is a lack of evidence concerning the possible effects of hamstring stretching in balance and gait biomechanics. So, this study was designed to investigate the potential effects of static hamstring stretching on the range of motion (ROM), dynamic balance, and biomechanical variables of gait in athletes with hamstring tightness.
 Materials and Methods: This study is a single-group, pretest-posttest clinical trial performed on semi-professional female athletes. Twelve female athletes aged 20 to 35 years with bilateral hamstring tightness received a single session of unilateral static hamstring stretching on their randomly selected side. All subjects were assessed for straight leg raise, popliteal angle (using standard goniometry), perceived hamstring tightness (using a visual analog scale). They completed single-leg standing and 15-m walking and running tasks before and immediately after the intervention. The biomechanical parameters, including gait-line length, swing duration, and stance duration in walking tasks, maximum total force and mean total force in running task, and center of pressure (COP) displacement and standard deviation during balance task were measured using OpenGo sensor insole system. The pre-post values were compared using the paired sample t-test, and the level of significance was 0.05.
 Results: The values for straight leg raise and popliteal angle significantly increased (P<0.05) compared with the baseline, while perceived tightness significantly decreased following stretching (P<0.001). The amplitude (P₌0.006) and standard deviation (P₌0.016) of COP displacement in the mediolateral direction during the single leg stance balance task were significantly decreased after the intervention. Stance duration in slow walking (P₌0.004), as well as stance duration (P₌0.012) and swing duration (P<0.001) in fast walking, were significantly decreased (P<0.05) after stretching. No change was observed in gait biomechanical variables during the running test (P>0.05).
 Conclusion: The results of this study indicate that static hamstring stretching can be a promising intervention not just for increasing hamstring flexibility but also for improving balance ability.

The Effect of Augmented Reality-Based Proprioceptive Training Program on Balance, Positioning Sensation and Flexibility in Healthy Young Adults: A Randomized Controlled Trial

“…Therefore, warming up, which includes stretching, results in beneficial results in exercise performance [ 37 ]. Salami et al (2021) announced that static stretching of the hamstring could have a positive effect on improving balance ability as well as increasing flexibility [ 38 ]. Furthermore, Mani et al (2021) compared static and PNF stretching in the short and long term and found that both groups greatly improved flexibility [ 36 ].…”

Association of Hamstring Tightness with Lower Extremity Injuries in Athletes (Analytical Cross-Sectional Study)

“…Stretching exercises, particularly eccentric training, have been shown to improve hamstring flexibility and reduce the risk of HSIs. (17,18) Additionally, regular massage and physiotherapy and kinesiotaping can help alleviate muscle tightness and improve ROM. (19,20) Moreover, incorporating flexibility training into the athletes' regular training regimen can help prevent the development of hamstring tightness.…”