Author(s): PAMBORIS, G.M., WILLIAMS, D.S.B., WELCH, L., POWELL, D.W., Institution: EUROPEAN UNIVERSITY CYPRUS, Country: CYPRUS, Abstract-ID: 1302

INTRODUCTION:
Recreational running, popular worldwide for its health benefits and accessibility, often leads to overuse injuries, affecting a significant percentage of runners annually (1). Running intensity and volume strain the musculoskeletal system, often leading to injuries (2). Hamstring flexibility is crucial in preventing injuries, yet optimal stretching techniques, such as static stretching (SS) and dynamic stretching (DS), on hamstring flexibility and lower extremity running biomechanics warrant further investigation. This study aimed to quantify the effects of SS and DS on hamstring flexibility and lower extremity running biomechanics in healthy athletes.
METHODS:
Eighteen healthy recreational runners with inflexible hamstrings (popliteal angle >25° away from zero) were randomly assigned to SS, DS, or control (CON) groups. Hamstring flexibility was measured using a standard goniometer, and running biomechanics were assessed using a motion analysis system and two force platforms before and after the six-week stretching program. Two-way repeated measures ANOVA and independent samples t-tests were performed.
RESULTS:
The six-week intervention significantly improved hamstring flexibility; with post-intervention assessment, the CONT had significantly greater popliteal angles than the SS (p=0.018) or DS groups (p=0.046). No differences in popliteal angles were observed between the SS and DS groups (p=0.192). While ankle and knee joint angles showed no significant changes, in the post-stretching intervention, the DS group exhibited significantly greater hip flexion at initial contact compared to CON (p=0.029), while the SS had similar hip joint angles at initial contact when compared to CON (p=0.088) and DS groups (p=0.241). No significant changes in ankle joint range of motion (RoM) during running were observed. No significant differences were found at the knee from pre- to post for all groups. However, the SS group had significantly greater RoM at the knee compared to the CON (p=0.013) and DS groups (p = 0.046). No differences in knee RoM were observed between the CON and DS groups (p=0.492). At the hip post-intervention, the CON group exhibited a significantly greater RoM than the DS group (p=0.029), while no differences in hip joint RoM were observed between the CON (p=0.118) and SS or SS and DS groups (p=0.423).
CONCLUSION:
SS and DS increased static RoM and altered lower extremity positions at initial contact during the stance phase of running. However, no significant differences were observed between the two techniques. Yet, moderate effect sizes indicate DS induces more pronounced changes. These findings support that stretching interventions can alter lower extremity running biomechanics. However, it is not clear whether these changes would be considered beneficial.
REFERENCES:
1) Fredericson & Misra, Sports Medicine, 2007
2) Taunton et al., British Journal of Sports Medicine, 2003