Publications
Altered Hamstring Mechanics and Strength Deficits Impair Balance Control in Athletes Following Hamstring Strain
Authors: Amornthep Jankaew 1, 2, Cheng-Feng Lin 1, 3
Affiliations:
- Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Integrated Neuro-Musculoskeletal, Chronic Disease, and Aging Research Engagement Center (ICARE Center), Department of Physical Therapy, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
- Physical Therapy Center, National Cheng Kung University Hospital, Tainan, Taiwan
Journal: Journal of Applied Biomechanics - July 2026, Ahead of Print (DOI: 10.1123/jab.2025-0359)
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Field & Applications:
- Sport
- Recovery from injury
- Balance / Postural control
- Musculoskeletal rehabilitation
Hamstring strains result in alterations to muscle function; however, evidence regarding how these changes affect balance performance remains limited. This study investigated the impact of altered hamstring function on balance control in athletes with hamstring injuries.
Thirty-two participants (16 injured hamstrings and 16 controls) participated in this study. Hamstring properties and strength were assessed to evaluate muscle function. Participants performed maximum lean forward in both single- and double-leg stances under eyes-closed and eyes-open conditions on a force platform. Then, the center of pressure was analyzed.
Injured athletes exhibited higher hamstring stiffness (P = .028) and decrement (P = .019), and lower strength (P = .024 at 0° and P = .005 at 90°). Also, they displayed a greater sway range in both the anteroposterior (P = .029) and mediolateral directions (P = .030), together with increased center of pressure velocity (P = .019) and a larger sway area (P = .020) during a forward lean task under eye-closed conditions.
Significant associations were identified between hamstring function and balance control. These findings indicate that alterations in hamstring function following muscle strains contribute to impaired balance control. This factor should be considered in training and rehabilitation for athletes recovering from hamstring injuries.
Keywords: hamstring injury, hamstring function, muscle mechanics, muscle strength, postural stability
In conclusion, athletes with hamstring injuries exhibited persistent deficits in muscle mechanical properties and function. Alterations in muscle function following injury demonstrated weak, task-specific correlations with poor balance performance, particularly during challenging postural tasks, such as forward leaning. These findings support the consideration of individualized poststrain rehabilitation programs that integrate sport-specific strengthening and targeted neuromuscular training to effectively restore balance control during demanding tasks.