This cross-sectional observational study investigated posterior chain muscle activation patterns in football players with and without a history of hamstring strain injury. Forty-two male athletes were assessed using surface electromyography (sEMG) during Nordic Hamstring Curl, Kettlebell Swing, and Supine Sliding Leg Curl exercises. Results demonstrated persistent deficits in biceps femoris, gluteus maximus, latissimus dorsi, and iliocostalis lumborum activation in previously injured athletes compared to controls, suggesting that neuromuscular alterations extend beyond the hamstring itself and may increase reinjury risk.

Inclusion Criteria:

• Male football players, aged 18-30 years
• Body mass index (BMI) between 18.5-24.9 kg/m²
• Voluntary participation and written informed consent
• Ability to perform all test exercises (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl)
• For injured group: unilateral hamstring strain within the past 6 months
• For control group: no hamstring injury within the past 6 months

Exclusion Criteria:

• Professional sports background
• Lower or upper extremity injury within the last year (other than index hamstring strain for the injured group)
• Neurological, musculoskeletal, respiratory, or cardiovascular conditions limiting participation
• Recent spinal surgery
• Acute low-back or lower-limb pain
• Sensory impairments interfering with performance
• History of malignancy

Forty-two male football players aged 18-30 years participated, including 21 with a history of unilateral hamstring strain injury and 21 healthy controls. All were recreational to semi-professional athletes with BMI within the normal range and able to complete functional posterior chain exercises.

De-identified individual participant data (IPD) that underlie the results reported in this article (text, tables, figures) will be made available upon reasonable request to the corresponding author, following publication. Data will be shared with qualified researchers for academic purposes, subject to ethical approval and institutional data protection policies. Supporting documents (study protocol, statistical analysis plan) may also be provided on request.

De-identified individual participant data (IPD), study protocol, and statistical analysis plan will be available beginning 6 months after publication of the main results article and will remain available for a period of 5 years thereafter.

Qualified researchers affiliated with academic or research institutions may request access to de-identified IPD, the study protocol, and the statistical analysis plan. Requests must be made in writing to the corresponding author and will be reviewed by the study team. Access will be granted for scientifically sound proposals, with data shared via secure transfer following institutional data protection policies.