Muscle Stretching ExerciseCOEESSNCT06469346
Comparison of Eccentric Exercise and Static Stretching on Muscle Flexibility
A study testing Nordic Hamstring Eccentric Exercise Training and Passive Hamstring Static Stretching Training in people with Muscle Stretching Exercise and Range of Motion, Articular, run by Universidad de La Frontera at 1 site in Chile.
Trial summary
Background: Muscle flexibility is a fundamental physical quality for body development, daily life and sports activities, and also for maintaining muscle quality during aging. Limited flexibility leads to an increased prevalence of musculoskeletal injury in general population and longer return to sports activities. Read more about this study
- Who is it for?
- Ages 18 to 35 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Muscle Stretching Exercise, Range of Motion, Articular
- What is being tested?
- Nordic Hamstring Eccentric Exercise Training and Passive Hamstring Static Stretching Training
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 42 participants
- Where
- 1 siteChile
- Study dates
- 3 Mar 2025to 30 Sep 2026
- 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 18 to 35 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Masculine University students between 18 and 35 years old
- Physically Inactive considering physical activity recommendations from World Health Organization
- Bilateral hamstring muscle stiffness defined as <160° in passive Knee Extension Angle Test
- Body Max Index 18,5 < BMI < 24,9 kg/m2
Who cannot join
- Lower back and lower limb (hip, thigh, knee, ankle) musculoskeletal injury in the last 12 months.
- Hamstring injury (strain, tendinopathy, tendon avulsion) previously during the period of life
- Dietary anabolic supplements consumption
- Musculoskeletal, cardiovascular, respiratory o similar health condition that limits participation on physical activity programs
- Regular resistance training (2 or more times per week, carrying out progressive training) in the previous 6 months
- Smoker (1 cigarette per day)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Comparison Between Eccentric Exercise and Static Stretching on Hamstring Muscle Flexibility in Healthy Young
Background: Muscle flexibility is a fundamental physical quality for body development, daily life and sports activities, and also for maintaining muscle quality during aging. Limited flexibility leads to an increased prevalence of musculoskeletal injury in general population and longer return to sports activities.
Among the existent strategies to increase muscle flexibility in sports training and physical rehabilitation, static stretching is commonly used by health and physical activity professionals. Its effectiveness in increasing flexibility has been widely demonstrated; however its effects on muscle strength and power remains controversial.
Therefore, eccentric resistance exercise has been proposed as an effective intervention for increasing muscle flexibility through structural changes on muscle architecture (pennation angle and fascicle length) with the additional benefit of resistance training on muscle strength and power. Nonetheless, its unknown if the increase in muscle flexibility through eccentric resistance exercise could be similar to what has been previously demonstrated with static stretching.
Read the detailed description
Hypothesis: The increase in hamstring flexibility after 6 weeks of eccentric resistance training in young males would be similar compared to 6 weeks static stretching training in the same population.
Goals: The primary aim of the study is to compare the effectiveness of 6 weeks eccentric resistance training vs 6 weeks static stretching training on hamstring flexibility in young males.
Specific Goals: Determine the effect of 6 weeks excentric exercise training and 6 weeks static stretching training on unilateral maximal isometric voluntary strength between both groups
To compare the effect of 6 weeks excentric exercise training and 6 weeks static stretching training in structural changes on muscle architecture (pennation angle, fascicle length and muscle thickness).
Methodology:
Study design: Forty two young males between 18 and 35 years will be divided into three groups: hamstring eccentric resistance training group (EEG, n=14), hamstring static stretching group (SSG, n=14) and control group (CG, n=14). Volunteers of eccentric resistance training group will be subjected to 6 weeks of Nordic hamstring exercise (3x/wk), while volunteers of static stretching group will be subjected to 6 weeks of hamstring passive static stretching (3x/wk). Control group will not attend any type of intervention. Before and after 6 weeks of training, Knee Extension Angle and Sit and Reach test will be performed for measuring hamstring flexibility. Unilateral Hamstring Isometric Maximal Voluntary Strength will be determined by load cell force transducer, and pennation angle, fascicle length and muscle thickness of Long Head Biceps Femoris will be conducted through muscle ultrasonography
Study parameters/endpoint:
The main study endpoint is the increase in hamstring flexibility assessed with Knee Extension Angle and Sit and Reach Test.
Secondary endpoints include Unilateral Hamstring Isometric Maximal Voluntary Strength (IMVS) and Architectural changes in Long Head Biceps Femoris muscle.
Other parameters include age, body weight, body height, body mass index (BMI), level of physical activity.
Expected results: With the proposed project, the investigators expect that eccentric exercise training will increase hamstring muscle flexibility at similar level compared with static stretching training. The findings will define the potential of eccentric exercise training on muscle flexibility in healthy participants. These results could expand the benefits of this type of exercise training focused on being included in populations with limited mobility such as elderly and injured populations
- Being tested
- Nordic Hamstring Eccentric Exercise Training, Passive Hamstring Static Stretching Training, Control Group
- Keywords
- Eccentric resistance exercise, Static Stretching, Muscle Flexibility, Range of Movement
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nordic Hamstring Eccentric Exercise TrainingOther
Warm up: stationary bycicle at 50 watts and 60 bpm Mobility exercises for hip and knee joint
Nordic eccentric exercise protocol:
- Week 1: 2 sets x 5 repetitions
- Week 2: 2 sets x 6 repetitions
- Week 3: 3 sets x 6 repetitions
- Week 4-6: 3 sets x 8 repetitions
Passive Hamstring Static Stretching TrainingOther
Warm up: stationary bycicle at 50 watts and 60 bpm Mobility exercises for hip and knee joint
- Week 1-2: 1 set x 2 repetitions of 30 seconds
- Week 3: 1 set x 3 repetitions of 30 seconds
- Week 4-6: 1 set x 3 reps of 40 seconds
Control GroupOther
No intervention
| Study group | Role | What they receive |
|---|---|---|
| Eccentric Exercise Group (EEG) | Experimental | These participants will be subjected to 6 weeks of Nordic hamstring eccentric exercise (3 times per week) Receives: Other: Nordic Hamstring Eccentric Exercise Training |
| Static Stretching Group (SSG) | Experimental | These participants will be subjected to 6 weeks of passive static stretching on hamstring muscle (3 times per week) Receives: Other: Passive Hamstring Static Stretching Training |
| Control Group | Other | These participants will not be under any type of treatment during the intervention protocol Receives: Other: Control Group |
What is being measured
The primary outcome is the main question the study is designed to answer.
Knee Extension Angle
The degree changes in passive knee extension will be assessed using Passive Knee Extension Angle Test after intervention
Measured: Before and after 6 weeks of training
Sit-and-Reach
The distance (in centimeters) of change on functional posterior chain flexibility will be obtained in Sit-and-Reach Test after intervention
Measured: Before and after 6 weeks of training
Secondary outcomes (4)
Maximal Isometric Voluntary Strength
Change in unilateral isometric hamstring strength will be evaluated with load cell force transducer after intervention
Measured: Before and after 6 weeks of training
Long Head Biceps Femoris Pennation Angle
Change in pennation angle will be measured using muscular ultrasound after intervention
Measured: Before and after 6 weeks of training
Long Head Biceps Femoris Fascicle Length
Change in fascicle length will be measured using muscular ultrasound after intervention
Measured: Before and after 6 weeks of training
Long Head Biceps Femoris Muscle Thickness
Change in muscle thickness will be measured using muscular ultrasound after intervention
Measured: Before and after 6 weeks of training
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jun 2024
- Study start3 Mar 2025
- Primary completion30 Dec 2025
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Muscle Stretching ExerciseStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 42 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Universidad de La Frontera
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gabriel Nasri Marzuca-Nassr, Universidad de La Frontera
- Investigators
- Gabriel N Marzuca-Nassr, Principal investigator, Universidad de La Frontera
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06469346
- Sponsor's protocol ID
- MGTFNG-2024
- Acronym
- COEESS
- Status last verified
- Jun 2026
- First submitted
- 13 Jun 2024
- Last updated
- 12 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 12 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison Between Eccentric Exercise and Static Stretching on Hamstring Muscle Flexibility in Healthy Young
- ClinicalTrials.gov ID
- NCT06469346
- Acronym / sponsor ID
- COEESS / MGTFNG-2024
- Keywords
- Eccentric resistance exercise, Static Stretching, Muscle Flexibility, Range of Movement
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 42 participants (estimated)
- Lead sponsor
- Universidad de La FronteraUniversity, hospital or other
- Study start
- 3 Mar 2025 (actual)
- Primary completion
- 30 Dec 2025 (actual)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 21 Jun 2024 (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.
Background: Muscle flexibility is a fundamental physical quality for body development, daily life and sports activities, and also for maintaining muscle quality during aging. Limited flexibility leads to an increased prevalence of musculoskeletal injury in general population and longer return to sports activities.
Among the existent strategies to increase muscle flexibility in sports training and physical rehabilitation, static stretching is commonly used by health and physical activity professionals. Its effectiveness in increasing flexibility has been widely demonstrated; however its effects on muscle strength and power remains controversial.
Therefore, eccentric resistance exercise has been proposed as an effective intervention for increasing muscle flexibility through structural changes on muscle architecture (pennation angle and fascicle length) with the additional benefit of resistance training on muscle strength and power. Nonetheless, its unknown if the increase in muscle flexibility through eccentric resistance exercise could be similar to what has been previously demonstrated with static stretching.
Detailed description
Hypothesis: The increase in hamstring flexibility after 6 weeks of eccentric resistance training in young males would be similar compared to 6 weeks static stretching training in the same population.
Goals: The primary aim of the study is to compare the effectiveness of 6 weeks eccentric resistance training vs 6 weeks static stretching training on hamstring flexibility in young males.
Specific Goals: Determine the effect of 6 weeks excentric exercise training and 6 weeks static stretching training on unilateral maximal isometric voluntary strength between both groups
To compare the effect of 6 weeks excentric exercise training and 6 weeks static stretching training in structural changes on muscle architecture (pennation angle, fascicle length and muscle thickness).
Methodology:
Study design: Forty two young males between 18 and 35 years will be divided into three groups: hamstring eccentric resistance training group (EEG, n=14), hamstring static stretching group (SSG, n=14) and control group (CG, n=14). Volunteers of eccentric resistance training group will be subjected to 6 weeks of Nordic hamstring exercise (3x/wk), while volunteers of static stretching group will be subjected to 6 weeks of hamstring passive static stretching (3x/wk). Control group will not attend any type of intervention. Before and after 6 weeks of training, Knee Extension Angle and Sit and Reach test will be performed for measuring hamstring flexibility. Unilateral Hamstring Isometric Maximal Voluntary Strength will be determined by load cell force transducer, and pennation angle, fascicle length and muscle thickness of Long Head Biceps Femoris will be conducted through muscle ultrasonography
Study parameters/endpoint:
The main study endpoint is the increase in hamstring flexibility assessed with Knee Extension Angle and Sit and Reach Test.
Secondary endpoints include Unilateral Hamstring Isometric Maximal Voluntary Strength (IMVS) and Architectural changes in Long Head Biceps Femoris muscle.
Other parameters include age, body weight, body height, body mass index (BMI), level of physical activity.
Expected results: With the proposed project, the investigators expect that eccentric exercise training will increase hamstring muscle flexibility at similar level compared with static stretching training. The findings will define the potential of eccentric exercise training on muscle flexibility in healthy participants. These results could expand the benefits of this type of exercise training focused on being included in populations with limited mobility such as elderly and injured populations
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Eccentric Exercise Group (EEG) | Experimental | Other: Nordic Hamstring Eccentric Exercise TrainingThese participants will be subjected to 6 weeks of Nordic hamstring eccentric exercise (3 times per week) |
| Static Stretching Group (SSG) | Experimental | Other: Passive Hamstring Static Stretching TrainingThese participants will be subjected to 6 weeks of passive static stretching on hamstring muscle (3 times per week) |
| Control Group | Other | Other: Control GroupThese participants will not be under any type of treatment during the intervention protocol |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Masculine University students between 18 and 35 years old
- Physically Inactive considering physical activity recommendations from World Health Organization
- Bilateral hamstring muscle stiffness defined as <160° in passive Knee Extension Angle Test
- Body Max Index 18,5 < BMI < 24,9 kg/m2
Key exclusion criteria (6 listed)
- Lower back and lower limb (hip, thigh, knee, ankle) musculoskeletal injury in the last 12 months.
- Hamstring injury (strain, tendinopathy, tendon avulsion) previously during the period of life
- Dietary anabolic supplements consumption
- Musculoskeletal, cardiovascular, respiratory o similar health condition that limits participation on physical activity programs
- Regular resistance training (2 or more times per week, carrying out progressive training) in the previous 6 months
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 Eccentric Exercise TrainingWarm up: stationary bycicle at 50 watts and 60 bpm Mobility exercises for hip and knee joint Nordic eccentric exercise protocol: * Week 1: 2 sets x 5 repetitions * Week 2: 2 sets x 6 repetitions * Week 3: 3 sets x 6 repetitions * Week 4-6: 3 sets x 8 repetitions | Other | Eccentric Exercise Group (EEG) |
| Passive Hamstring Static Stretching TrainingWarm up: stationary bycicle at 50 watts and 60 bpm Mobility exercises for hip and knee joint * Week 1-2: 1 set x 2 repetitions of 30 seconds * Week 3: 1 set x 3 repetitions of 30 seconds * Week 4-6: 1 set x 3 reps of 40 seconds | Other | Static Stretching Group (SSG) |
| Control GroupNo intervention | Other | Control Group |
Primary outcome
Knee Extension Angle
Time frame: Before and after 6 weeks of training
The degree changes in passive knee extension will be assessed using Passive Knee Extension Angle Test after intervention
Sit-and-Reach
Time frame: Before and after 6 weeks of training
The distance (in centimeters) of change on functional posterior chain flexibility will be obtained in Sit-and-Reach Test after intervention
4 secondary outcomes
Maximal Isometric Voluntary Strength
Time frame: Before and after 6 weeks of training
Long Head Biceps Femoris Pennation Angle
Time frame: Before and after 6 weeks of training
Long Head Biceps Femoris Fascicle Length
Time frame: Before and after 6 weeks of training
Long Head Biceps Femoris Muscle Thickness
Time frame: Before and after 6 weeks of training
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 12 Jun 2026.
- Individual participant dataSharing planned: Undecided
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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.
Gabriel N Marzuca-Nassr principal investigator
Universidad de La Frontera
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 Eccentric Exercise Training and Passive Hamstring Static Stretching Training in people with Muscle Stretching Exercise and Range of Motion, Articular, run by Universidad de La Frontera at 1 site in Chile.
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 4 inclusion and 6 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: enrolling by invitation, as of the sponsor's last update on 12 Jun 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 Chile. 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?
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?
Knee Extension Angle (time frame: Before and after 6 weeks of training). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 Jun 2026.