Muscle StrengthNCT07705698
Nordic vs Blood Flow Restriction Nordic Exercise in Elite Female Pole Vaulters
A study testing Nordic Hamstring Exercise and Blood Flow Restriction-Assisted Nordic Hamstring Exercise in people with Muscle Strength and Athletic Performance, run by Toros University at 1 site in Turkey (Türkiye).
Trial summary
The purpose of this randomized controlled trial is to compare the effects of Nordic Hamstring Exercise (NHE) and Blood Flow Restriction-assisted Nordic Hamstring Exercise (BFR-NHE) on hamstring muscle strength, muscle morphology, and functional performance in elite adolescent female pole vaulters. Read more about this study
- Who is it for?
- Ages 12 to 18 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Muscle Strength, Athletic Performance, Hamstring Adaptation
- What is being tested?
- Nordic Hamstring Exercise and Blood Flow Restriction-Assisted Nordic Hamstring Exercise
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 36 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 27 May 2026to Apr 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
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 12 to 18 years
- Women only
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Female athletes aged between 12 and 18 years.
- Elite pole vault athletes actively participating in organized training and competition.
- Minimum of 1 year of regular pole vault training experience.
- Participation in regular training at least 3 times per week.
- Ability to participate in an 8-week exercise program.
- Written informed assent from the athlete and written informed consent from a parent or legal guardian.
Who cannot join
- Any lower extremity musculoskeletal injury within the previous 6 months.
- Previous hamstring muscle surgery.
- Current pain or injury limiting sports participation.
- Neurological disorders affecting movement or balance.
- Cardiovascular conditions contraindicating exercise training or blood flow restriction.
- Any contraindication to blood flow restriction training.
- Participation in another structured hamstring strengthening program during the study period.
- Inability or unwillingness to comply with study procedures.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Adana Olympic Preparation Center
Adana
Burçin Uğur, PHD, +90 507 772 17 72, burcnugur@yahoo.com
About this study
Official title: Effects of Nordic Hamstring Exercise and Blood Flow Restriction-Assisted Nordic Hamstring Exercise on Hamstring Strength, Muscle Morphology and Functional Performance in Elite Adolescent Female Pole Vaulters: A Randomized Controlled Trial
The purpose of this randomized controlled trial is to compare the effects of Nordic Hamstring Exercise (NHE) and Blood Flow Restriction-assisted Nordic Hamstring Exercise (BFR-NHE) on hamstring muscle strength, muscle morphology, and functional performance in elite adolescent female pole vaulters. Thirty-six athletes aged 12-18 years will be randomly assigned to a Nordic Hamstring Exercise group, a Blood Flow Restriction-assisted Nordic Hamstring Exercise group, or a control group. Intervention groups will participate in supervised exercise training three times per week for eight weeks, while the control group will continue routine sports training. Outcomes will be assessed before and after the intervention period.
Read the detailed description
Hamstring muscles play a crucial role in sprinting, acceleration, deceleration, and explosive athletic performance. Nordic Hamstring Exercise is widely recommended for increasing eccentric hamstring strength and reducing injury risk. However, evidence regarding the additional effects of blood flow restriction during Nordic Hamstring Exercise is limited, particularly in elite adolescent female athletes.
This randomized controlled trial aims to investigate whether adding blood flow restriction to Nordic Hamstring Exercise enhances adaptations in hamstring muscle strength, muscle morphology, and functional performance compared with conventional Nordic Hamstring Exercise and routine training alone.
Thirty-six elite adolescent female pole vaulters aged 12-18 years will be recruited from the Turkish Olympic Preparation Center. Participants will be allocated using block randomization into three groups:
Nordic Hamstring Exercise Group Blood Flow Restriction Nordic Hamstring Exercise Group Control Group Intervention groups will perform supervised exercise sessions three times weekly for eight weeks. The control group will continue regular training activities without additional hamstring-specific intervention.
Assessments will include hamstring muscle strength measured with a MicroFET2 handheld dynamometer, muscle morphology assessed using ultrasonography, and functional performance evaluated using a 30-meter sprint test.
- Being tested
- Nordic Hamstring Exercise, Blood Flow Restriction-Assisted Nordic Hamstring Exercise
- Keywords
- Nordic Hamstring Exercise, Blood Flow Restriction Training, Ultrasonography, Functional Performance, Adolescent Athletes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nordic Hamstring ExerciseBehavioural
Participants will perform a supervised Nordic Hamstring Exercise program three times per week for 8 weeks in addition to their routine pole vault training. The exercise program will be progressively increased according to participant tolerance and training progression.
Blood Flow Restriction-Assisted Nordic Hamstring ExerciseBehavioural
articipants will perform a supervised Nordic Hamstring Exercise program combined with individualized blood flow restriction training three times per week for 8 weeks in addition to their routine pole vault training. Blood flow restriction will be applied using pneumatic cuffs at a predetermined percentage of arterial occlusion pressure.
| Study group | Role | What they receive |
|---|---|---|
| Nordic Hamstring Exercise | Experimental | Participants will perform a supervised Nordic Hamstring Exercise program three times per week for 8 weeks in addition to their routine pole vault training. Receives: Behavioral: Nordic Hamstring Exercise |
| Blood Flow Restriction-Assisted Nordic Hamstring Exercise | Experimental | Participants will perform Nordic Hamstring Exercise combined with blood flow restriction training three times per week for 8 weeks in addition to their routine pole vault training. Receives: Behavioral: Blood Flow Restriction-Assisted Nordic Hamstring Exercise |
| Control | No intervention | Participants will continue their routine sports training without additional hamstring-specific exercise intervention. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Hamstring Muscle Strength
Isometric hamstring muscle strength will be assessed bilaterally using a MicroFET2 handheld dynamometer. Three measurements will be recorded and the average value will be used for analysis.
Measured: Baseline and 8 weeks
Hamstring Muscle Thickness
Hamstring muscle thickness will be evaluated bilaterally using ultrasonography. Three measurements will be obtained and averaged.
Measured: Baseline and 8 weeks
Hamstring Cross-Sectional Area
Cross-sectional area of the hamstring muscle will be assessed bilaterally using ultrasonography.
Measured: Baseline and 8 weeks
Secondary outcomes (1)
30-Meter Sprint Performance
Sprint performance will be assessed using a 30-meter sprint test. The average of three trials will be used for analysis.
Measured: Baseline and 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jul 2026
- Study start27 May 2026
- Primary completionMar 2027 (estimated)
- Study completionApr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Muscle StrengthStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants will be allocated to one of three parallel groups: Nordic Hamstring Exercise, Blood Flow Restriction-assisted Nordic Hamstring Exercise, or control. Intervention groups will complete supervised training three times weekly for eight weeks, while the control group will continue routine training. Outcomes will be assessed before and after the intervention period.
- Masking
- None (open label)
- Enrolment
- 36 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Toros University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Idil Esin Unlu, Toros University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07705698
- Sponsor's protocol ID
- 25.05.2026-05/82
- Status last verified
- Jul 2026
- First submitted
- 6 Jul 2026
- Last updated
- 15 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Ripley NJ, Cuthbert M, Comfort P, McMahon JJ. Effect of additional Nordic hamstring exercise or sprint training on the modifiable risk factors of hamstring strain injuries and performance. PLoS One. 2023 Mar 2;18(3):e0281966. doi: 10.1371/journal.pone.0281966. eCollection 2023.
PubMed 36862645Vianna KB, Rodrigues LG, Oliveira NT, Ribeiro-Alvares JB, Baroni BM. A Preseason Training Program With the Nordic Hamstring Exercise Increases Eccentric Knee Flexor Strength and Fascicle Length in Professional Female Soccer Players. Int J Sports Phys Ther. 2021 Apr 1;16(2):459-467. doi: 10.26603/001c.19452.
PubMed 33842041
Study at a glance
From the registry record, last updated by the sponsor on 15 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Nordic Hamstring Exercise and Blood Flow Restriction-Assisted Nordic Hamstring Exercise on Hamstring Strength, Muscle Morphology and Functional Performance in Elite Adolescent Female Pole Vaulters: A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07705698
- Acronym / sponsor ID
- 25.05.2026-05/82
- Keywords
- Nordic Hamstring Exercise, Blood Flow Restriction Training, Ultrasonography, Functional Performance, Adolescent Athletes
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 36 participants (estimated)
- Lead sponsor
- Toros UniversityUniversity, hospital or other
- Study start
- 27 May 2026 (actual)
- Primary completion
- Mar 2027 (estimated)
- Study completion
- Apr 2027 (estimated)
- First posted
- 15 Jul 2026 (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.
The purpose of this randomized controlled trial is to compare the effects of Nordic Hamstring Exercise (NHE) and Blood Flow Restriction-assisted Nordic Hamstring Exercise (BFR-NHE) on hamstring muscle strength, muscle morphology, and functional performance in elite adolescent female pole vaulters. Thirty-six athletes aged 12-18 years will be randomly assigned to a Nordic Hamstring Exercise group, a Blood Flow Restriction-assisted Nordic Hamstring Exercise group, or a control group. Intervention groups will participate in supervised exercise training three times per week for eight weeks, while the control group will continue routine sports training. Outcomes will be assessed before and after the intervention period.
Detailed description
Hamstring muscles play a crucial role in sprinting, acceleration, deceleration, and explosive athletic performance. Nordic Hamstring Exercise is widely recommended for increasing eccentric hamstring strength and reducing injury risk. However, evidence regarding the additional effects of blood flow restriction during Nordic Hamstring Exercise is limited, particularly in elite adolescent female athletes.
This randomized controlled trial aims to investigate whether adding blood flow restriction to Nordic Hamstring Exercise enhances adaptations in hamstring muscle strength, muscle morphology, and functional performance compared with conventional Nordic Hamstring Exercise and routine training alone.
Thirty-six elite adolescent female pole vaulters aged 12-18 years will be recruited from the Turkish Olympic Preparation Center. Participants will be allocated using block randomization into three groups:
Nordic Hamstring Exercise Group Blood Flow Restriction Nordic Hamstring Exercise Group Control Group Intervention groups will perform supervised exercise sessions three times weekly for eight weeks. The control group will continue regular training activities without additional hamstring-specific intervention.
Assessments will include hamstring muscle strength measured with a MicroFET2 handheld dynamometer, muscle morphology assessed using ultrasonography, and functional performance evaluated using a 30-meter sprint test.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- Participants will be allocated to one of three parallel groups: Nordic Hamstring Exercise, Blood Flow Restriction-assisted Nordic Hamstring Exercise, or control. Intervention groups will complete supervised training three times weekly for eight weeks, while the control group will continue routine training. Outcomes will be assessed before and after the intervention period.
| Arm | Type | Receives |
|---|---|---|
| Nordic Hamstring Exercise | Experimental | Behavioral: Nordic Hamstring ExerciseParticipants will perform a supervised Nordic Hamstring Exercise program three times per week for 8 weeks in addition to their routine pole vault training. |
| Blood Flow Restriction-Assisted Nordic Hamstring Exercise | Experimental | Behavioral: Blood Flow Restriction-Assisted Nordic Hamstring ExerciseParticipants will perform Nordic Hamstring Exercise combined with blood flow restriction training three times per week for 8 weeks in addition to their routine pole vault training. |
| Control | No intervention | –Participants will continue their routine sports training without additional hamstring-specific exercise intervention. |
Who may qualify
- Ages
- 12 to 18 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (6 listed)
- Female athletes aged between 12 and 18 years.
- Elite pole vault athletes actively participating in organized training and competition.
- Minimum of 1 year of regular pole vault training experience.
- Participation in regular training at least 3 times per week.
- Ability to participate in an 8-week exercise program.
Key exclusion criteria (8 listed)
- Any lower extremity musculoskeletal injury within the previous 6 months.
- Previous hamstring muscle surgery.
- Current pain or injury limiting sports participation.
- Neurological disorders affecting movement or balance.
- Cardiovascular conditions contraindicating exercise training or blood flow restriction.
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 ExerciseParticipants will perform a supervised Nordic Hamstring Exercise program three times per week for 8 weeks in addition to their routine pole vault training. The exercise program will be progressively increased according to participant tolerance and training progression. | Behavioural | Nordic Hamstring Exercise |
| Blood Flow Restriction-Assisted Nordic Hamstring Exercisearticipants will perform a supervised Nordic Hamstring Exercise program combined with individualized blood flow restriction training three times per week for 8 weeks in addition to their routine pole vault training. Blood flow restriction will be applied using pneumatic cuffs at a predetermined percentage of arterial occlusion pressure. | Behavioural | Blood Flow Restriction-Assisted Nordic Hamstring Exercise |
Primary outcome
Hamstring Muscle Strength
Time frame: Baseline and 8 weeks
Isometric hamstring muscle strength will be assessed bilaterally using a MicroFET2 handheld dynamometer. Three measurements will be recorded and the average value will be used for analysis.
Hamstring Muscle Thickness
Time frame: Baseline and 8 weeks
Hamstring muscle thickness will be evaluated bilaterally using ultrasonography. Three measurements will be obtained and averaged.
Hamstring Cross-Sectional Area
Time frame: Baseline and 8 weeks
Cross-sectional area of the hamstring muscle will be assessed bilaterally using ultrasonography.
1 secondary outcome
30-Meter Sprint Performance
Time frame: Baseline and 8 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Jul 2026.
- Results publication: PubMed 36862645Ripley NJ, Cuthbert M, Comfort P, McMahon JJ. Effect of additional Nordic hamstring exercise or sprint training on the modifiable risk factors of hamstring strain injuries and performance. PLoS One. 2023 Mar 2;18(3):e0281966. doi: 10.1371/journal.pone.0281966. eCollection 2023.
- Results publication: PubMed 33842041Vianna KB, Rodrigues LG, Oliveira NT, Ribeiro-Alvares JB, Baroni BM. A Preseason Training Program With the Nordic Hamstring Exercise Increases Eccentric Knee Flexor Strength and Fascicle Length in Professional Female Soccer Players. Int J Sports Phys Ther. 2021 Apr 1;16(2):459-467. doi: 10.26603/001c.19452.
- Individual participant dataSharing planned: No
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Nordic Hamstring Exercise and Blood Flow Restriction-Assisted Nordic Hamstring Exercise in people with Muscle Strength and Athletic Performance, run by Toros 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 8 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: looking for participants now, as of the sponsor's last update on 15 Jul 2026. 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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact İdil Esin Ünlü, Assist. Prof. Dr. (+90 506 515 66 22, idil.unlu@toros.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Hamstring Muscle Strength (time frame: Baseline and 8 weeks). The study lists 3 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 NCT07705698, which also lists 2 linked publications.
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 15 Jul 2026.