Athletic Injuries, Muscle Strain, Neuromuscular Diseases
Conditions
Keywords
Hamstring Muscles, Electromyography, Athletic Injuries, Muscle, Skeletal, Exercise Therapy, Soccer, Rehabilitation, Biceps Femoris, Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Leg Curl, Reinjury Prevention
Brief summary
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.
Interventions
OTHERNordic Hamstring Curl (NHC)
Knee-dominant eccentric hamstring strengthening exercise performed on a padded surface. Participants control the descent of the torso while knees remain fixed, emphasizing eccentric activation of hamstring muscles.
OTHERKettlebell Swing (KS)
Hip-dominant ballistic movement involving rapid hip flexion-extension using a kettlebell (16-20 kg depending on participant's ability). Each repetition includes concentric, isometric, and eccentric phases standardized by metronome pacing.
OTHERSupine Sliding Single-Leg Curl (SSLC)
Closed-chain exercise performed in supine position with heels placed on sliding discs. One leg is extended while the other leg performs concentric-eccentric sliding curl.
Sponsors
Mersin University
T.C. Dumlupınar Üniversitesi
Eskisehir Technical University
Istanbul Gelisim University
Çanakkale Onsekiz Mart University
Saglik Bilimleri Universitesi
Manisa Celal Bayar University
Ankara Yildirim Beyazıt University
Study design
Observational model
OTHER
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
MALE
Age
18 Years to 30 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Gluteus Maximus Activation (%MVIC) | Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl) | Surface EMG amplitude (RMS) normalized to MVIC, averaged across three functional exercises. Mean %MVIC compared between groups. |
| Biceps Femoris Long Head Activation (%MVIC) | Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl) | Surface EMG amplitude (RMS) normalized to MVIC. Mean %MVIC across repetitions compared between injured and healthy athletes. |
| Latissimus Dorsi Activation (%MVIC) | Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl) | Surface EMG amplitude (RMS) normalized to MVIC, averaged across three functional exercises. Mean %MVIC compared between groups. |
| Iliocostalis Lumborum Activation (%MVIC) | Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl) | Surface EMG amplitude (RMS) normalized to MVIC. Mean %MVIC across repetitions compared between injured and healthy athletes. |
Countries
Turkey (Türkiye)
Outcome results
None listed