Posterior Chain EMG Patterns in Athletes With and Without Hamstring Injury

Persistent Neuromuscular Deficits in the Posterior Kinetic Chain Following Hamstring Strain Injury: A Cross-Sectional Study Using EMG

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