Muscle StrainNCT07171385
Posterior Chain EMG Patterns in Athletes With and Without Hamstring Injury
An observational study of Muscle Strain and Neuromuscular Diseases, run by Ankara Yildirim Beyazıt University at 1 site in Turkey (Türkiye).
Trial 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… Read more about this study
- Who is it for?
- Ages 18 to 30 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Muscle Strain, Neuromuscular Diseases, Athletic Injuries
- What is being tested?
- Nordic Hamstring Curl (NHC), Kettlebell Swing (KS) and Supine Sliding Single-Leg Curl (SSLC)
- How many people
- 42 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 11 Nov 2023to 10 Mar 2024
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 30 years
- Men only
- Healthy volunteers accepted
- Adult
Study population: 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.
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
University of Health Sciences
Ankara, Etlik, 06100
About this study
Official title: 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.
- Conditions
- Muscle Strain, Neuromuscular Diseases, Athletic Injuries
- Being tested
- Nordic Hamstring Curl (NHC), Kettlebell Swing (KS), Supine Sliding Single-Leg Curl (SSLC)
- 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
- Medical subject headings
- Sprains and Strains, Neuromuscular Diseases, Athletic Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nordic Hamstring Curl (NHC)Other
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.
Kettlebell Swing (KS)Other
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.
Supine Sliding Single-Leg Curl (SSLC)Other
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.
| Study group | Role | What they receive |
|---|---|---|
| Injured Group | Male football players aged 18-30 years with a history of unilateral hamstring strain injury (HSI) within the past 6 months, BMI 18.5-24.9 kg/m², able to perform study exercises (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Leg Curl). Surface electromyography (sEMG) was used to measure activation of biceps femoris, gluteus maximus, latissimus dorsi, and iliocostalis lumborum during a single session. No interventions were applied (observational study). Receives: Other: Nordic Hamstring Curl (NHC); Other: Kettlebell Swing (KS); Other: Supine Sliding Single-Leg Curl (SSLC) | |
| Healthy Control Group | Male football players aged 18-28 years, no history of hamstring strain injury in the past 6 months, BMI 18.5-24.9 kg/m², straight-leg raise on dominant limb <80°, able to perform study exercises (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Leg Curl). Surface electromyography (sEMG) measured activation of biceps femoris, gluteus maximus, latissimus dorsi, and iliocostalis lumborum in a single session. No interventions were applied (observational study). Receives: Other: Nordic Hamstring Curl (NHC); Other: Kettlebell Swing (KS); Other: Supine Sliding Single-Leg Curl (SSLC) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Gluteus Maximus Activation (%MVIC)
Surface EMG amplitude (RMS) normalized to MVIC, averaged across three functional exercises. Mean %MVIC compared between groups.
Measured: Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl)
Biceps Femoris Long Head Activation (%MVIC)
Surface EMG amplitude (RMS) normalized to MVIC. Mean %MVIC across repetitions compared between injured and healthy athletes.
Measured: Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl)
Latissimus Dorsi Activation (%MVIC)
Surface EMG amplitude (RMS) normalized to MVIC, averaged across three functional exercises. Mean %MVIC compared between groups.
Measured: Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl)
Iliocostalis Lumborum Activation (%MVIC)
Surface EMG amplitude (RMS) normalized to MVIC. Mean %MVIC across repetitions compared between injured and healthy athletes.
Measured: Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Sep 2025
- Study start11 Nov 2023
- Primary completion10 Dec 2023
- Study completion10 Mar 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Muscle StrainStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Cross-sectional
- Enrolment
- 42 participants (actual)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Ankara Yildirim Beyazıt University
- Sponsor type
- University, hospital or other
- Collaborators
- Mersin University, T.C. Dumlupınar Üniversitesi, Eskisehir Technical University, Istanbul Gelisim University, Çanakkale Onsekiz Mart University, Saglik Bilimleri Universitesi, Manisa Celal Bayar University
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07171385
- Sponsor's protocol ID
- 2023-350
- Status last verified
- Sep 2025
- First submitted
- 6 Sep 2025
- Last updated
- 12 Sep 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.
Publications
Gulgosteren E, Yuksel O, Gurol B, Yildirim O, Atar O, Soylu C, Altundag E, Acar G. Persistent neuromuscular deficits in the posterior kinetic chain following hamstring strain injury: EMG insights from nordic hamstring curl, kettlebell swing, and supine sliding leg curl. BMC Sports Sci Med Rehabil. 2025 Nov 29;18(1):6. doi: 10.1186/s13102-025-01435-5.
PubMed 41318473
Study at a glance
From the registry record, last updated by the sponsor on 12 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Persistent Neuromuscular Deficits in the Posterior Kinetic Chain Following Hamstring Strain Injury: A Cross-Sectional Study Using EMG
- ClinicalTrials.gov ID
- NCT07171385
- Acronym / sponsor ID
- 2023-350
- Conditions
- Muscle Strain, Neuromuscular Diseases, Athletic Injuries
- Keywords
- Hamstring Muscles, Electromyography, Athletic Injuries, Muscle, Skeletal, Exercise Therapy, Soccer, Rehabilitation, Biceps Femoris
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 42 participants (actual)
- Lead sponsor
- Ankara Yildirim Beyazıt UniversityUniversity, hospital or other
- Collaborators
- Mersin University, T.C. Dumlupınar Üniversitesi, Eskisehir Technical University, Istanbul Gelisim University, Çanakkale Onsekiz Mart University, Saglik Bilimleri Universitesi, Manisa Celal Bayar University
- Study start
- 11 Nov 2023 (actual)
- Primary completion
- 10 Dec 2023 (actual)
- Study completion
- 10 Mar 2024 (actual)
- First posted
- 12 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Other
- Time perspective
- Cross-sectional
- Target follow-up
- 1 Day
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Injured Group | – | Other: Nordic Hamstring Curl (NHC), Other: Kettlebell Swing (KS), Other: Supine Sliding Single-Leg Curl (SSLC)Male football players aged 18-30 years with a history of unilateral hamstring strain injury (HSI) within the past 6 months, BMI 18.5-24.9 kg/m², able to perform study exercises (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Leg Curl). Surface electromyography (sEMG) was used to measure activation of biceps femoris, gluteus maximus, latissimus dorsi, and iliocostalis lumborum during a single session. No interventions were applied (observational study). |
| Healthy Control Group | – | Other: Nordic Hamstring Curl (NHC), Other: Kettlebell Swing (KS), Other: Supine Sliding Single-Leg Curl (SSLC)Male football players aged 18-28 years, no history of hamstring strain injury in the past 6 months, BMI 18.5-24.9 kg/m², straight-leg raise on dominant limb <80°, able to perform study exercises (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Leg Curl). Surface electromyography (sEMG) measured activation of biceps femoris, gluteus maximus, latissimus dorsi, and iliocostalis lumborum in a single session. No interventions were applied (observational study). |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- 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.
Key inclusion criteria (6 listed)
- 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
Key exclusion criteria (7 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Nordic 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. | Other | Healthy Control Group, Injured Group |
| Kettlebell 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. | Other | Healthy Control Group, Injured Group |
| Supine 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. | Other | Healthy Control Group, Injured Group |
Primary outcome
Gluteus Maximus Activation (%MVIC)
Time frame: 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)
Time frame: 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)
Time frame: 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)
Time frame: 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.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Sep 2025.
- Derived from this study: PubMed 41318473Gulgosteren E, Yuksel O, Gurol B, Yildirim O, Atar O, Soylu C, Altundag E, Acar G. Persistent neuromuscular deficits in the posterior kinetic chain following hamstring strain injury: EMG insights from nordic hamstring curl, kettlebell swing, and supine sliding leg curl. BMC Sports Sci Med Rehabil. 2025 Nov 29;18(1):6. doi: 10.1186/s13102-025-01435-5.
- Individual participant dataSharing planned: Yes. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Muscle Strain and Neuromuscular Diseases, run by Ankara Yildirim Beyazıt University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Gluteus Maximus Activation (%MVIC) (time frame: Single laboratory visit; measurements during 3 repetitions of each exercise (Nordic Hamstring Curl, Kettlebell Swing, Supine Sliding Single-Leg Curl)). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07171385, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Sep 2025.