HealthyNCT06987344
How Eccentric Closed Chain Training Affects Knee Strength and Muscle Properties in Soccer Players
A study testing Field-based closed kinetic chain exercise with progressively increased time under tension and Regular soccer training routines in people with Healthy, run by University of Americas - Chili at 1 site in Chile.
Trial summary
The goal of this study is to learn whether a 6-week lower-body training program using closed kinetic chain (CKC) exercises with slow, controlled movements (called "eccentric time under tension") can improve leg muscle strength and muscle-tendon viscoelastic properties in male university soccer players. Read more about this study
- Who is it for?
- Ages 18 to 25 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- Field-based closed kinetic chain exercise with progressively increased time under tension and Regular soccer training routines
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteChile
- Study dates
- 6 Jan 2025to 31 Mar 2025
- Phase
- Interventional
- 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 25 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Absence of any medical conditions that could compromise their ability to participate.
- Active membership in their university's soccer team for a minimum of one year.
Who cannot join
- Musculoskeletal injuries reported in the two months prior to the start of the study.
- Surgical interventions involving the lower limbs within the past year.
Trial locations and contacts
1 site in 1 country.
Chile1 site
Human Movement Analysis Laboratory
Viña del Mar, V región/Valparaíso, 2340000
About this study
Official title: Field-based Closed Kinetic Chain Training With Progressive Eccentric Time Under Tension: Effects on Knee Strength and Lower Limb Viscoelasticity in Soccer Players: a Randomized Controlled Trial
The goal of this study is to learn whether a 6-week lower-body training program using closed kinetic chain (CKC) exercises with slow, controlled movements (called "eccentric time under tension") can improve leg muscle strength and muscle-tendon viscoelastic properties in male university soccer players.
The Main Questions Are:
Read more
- Does this type of training improve knee strength?
- Does it change the way muscles and tendons respond to movement or pressure?
What Will Participants Do?
- Join one of two groups: one does the CKC training program, the other continues regular soccer training
- Train twice a week for 6 weeks
- Have their leg strength tested using special equipment
- Have their muscle and tendon properties measured with a handheld device
Read the detailed description
This randomized controlled trial investigated the effects of a 6-week, field-based closed kinetic chain (CKC) exercise program with progressively increased eccentric time under tension (TUT) on isokinetic knee performance and lower limb muscle-tendon viscoelastic properties in male university soccer players.
A total of 24 healthy participants were randomly assigned (1:1) to either an intervention group performing supervised CKC exercises or an active control group that maintained routine soccer training. The CKC training was performed twice per week and included progressive increases in eccentric phase duration and external loading. Training volume was quantified using both mechanical load and eccentric TUT. Each session lasted approximately 35 minutes and included a variety of multi-joint, bilateral and unilateral exercises performed on a soccer field.
Baseline and post-intervention assessments were conducted using:
Isokinetic dynamometry (Biodex System 3 Pro) to measure concentric peak torque, mean power, and agonist/antagonist ratio at 60°/s.
MyotonPRO handheld myotonometer to assess oscillation frequency and stiffness of specific lower limb muscles (VM, VL, ST, GM) and tendons (Achilles, patellar).
Muscle and tendon assessments were performed following standardized anatomical landmarks. To ensure data reliability, repeated trials were used and measurements with high variability were repeated. Pre-testing familiarization was implemented to reduce learning effects.
The statistical approach included a two-way repeated measures ANOVA to compare group (CKC vs. control) and time (pre vs. post) effects. Holm-Sidak post hoc tests were applied when appropriate, and effect sizes were interpreted using eta squared (η²). All data analyses were conducted using JASP software (v0.18.3).
The protocol was reviewed and approved by an institutional ethics committee , and written informed consent was obtained from all participants. No serious adverse events were reported, and dropout was minimal (n = 4). No dietary interventions were applied; however, participants were instructed to maintain consistent routines throughout.
- Conditions
- Healthy
- Being tested
- Field-based closed kinetic chain exercise with progressively increased time under tension, Regular soccer training routines
- Keywords
- Exercise therapy, Muscle strength, Lower extremity, Tendons
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Field-based closed kinetic chain exercise with progressively increased time under tensionOther
This intervention is uniquely characterized by the integration of field-based closed kinetic chain (CKC) exercises with a systematically increased eccentric time under tension (TUT), specifically tailored for university-level soccer players. Unlike conventional strength training protocols, which are often gym-based and rely on traditional resistance machines or free weights, this program emphasizes functional, sport-specific movement patterns performed on the field, enhancing ecological validity and transfer to soccer performance.
Regular soccer training routinesOther
Trained three times a week: two days were dedicated to functional and tactical on-field training, while the third day was reserved for a two-hour gym session focused on flexibility, muscular strength, and endurance development.
| Study group | Role | What they receive |
|---|---|---|
| Active Control Group | Active comparator | Maintained their customary daily activities and regular soccer training routines: Trained three times a week, two days were dedicated to functional and tactical on-field training, while the third day was reserved for a two-hour gym session focused on flexibility, muscular strength, and endurance development. Receives: Other: Regular soccer training routines |
| Closed Kinetic Chain Group | Experimental | In addition to the same activities as the active cotrol group, participants performed five to seven different closed kinetic chain drills during the two days of field-based training, completing two to three sets per drill and eight to fourteen repetitions per set. The training volume underwent gradual increments over the course of every week. The total training volume for externally loaded CKC exercises was calculated by summing sets × repetitions × load (kg), yielding a cumulative volume of approximately 10,863 kg over 12 sessions. For exercises involving bodyweight or elastic resistance, training volume was estimated using time under tension (TUT), computed as the product of repetitions and eccentric phase duration. The cumulative TUT throughout the 6-week protocol amounted to 9,300 seconds (155 minutes) of eccentric loading. Receives: Other: Field-based closed kinetic chain exercise with progressively increased time under tension; Other: Regular soccer training routines |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from baseline in the rotational peak torque relative to body mass at 6 weeks
Assessed using a Biodex® System 3 Pro isokinetic dynamometer (Shirley, NY, USA), with a validated accuracy of ±1%.
Testing was performed at 60°/s angular velocity, a standard velocity for evaluating maximal voluntary muscle contraction.
Participants were seated with their hips and knees at approximately 90° flexion. The dominant leg was tested and stabilized using straps at the trunk, thigh, and lower leg. Gravity correction was applied prior to testing.
Following a 5-minute warm-up and 3 submaximal practice repetitions, each participant performed 3 maximal concentric repetitions of knee extension and flexion.
The dominant leg was defined as the preferred leg for kicking, confirmed via observation of a standardized ball-kicking task.
Measured: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Change from baseline in the rotational mean power at 6 weeks
Assessed using a Biodex® System 3 Pro isokinetic dynamometer (Shirley, NY, USA), with a validated accuracy of ±1%.
Testing was performed at 60°/s angular velocity, a standard velocity for evaluating maximal voluntary muscle contraction.
Participants were seated with their hips and knees at approximately 90° flexion. The dominant leg was tested and stabilized using straps at the trunk, thigh, and lower leg. Gravity correction was applied prior to testing.
Following a 5-minute warm-up and 3 submaximal practice repetitions, each participant performed 3 maximal concentric repetitions of knee extension and flexion.
The dominant leg was defined as the preferred leg for kicking, confirmed via observation of a standardized ball-kicking task.
Measured: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Secondary outcomes (3)
Change from baseline in the agonist/antagonist strength ratio at 6 weeks
Assessed using a Biodex® System 3 Pro isokinetic dynamometer (Shirley, NY, USA), with a validated accuracy of ±1%. Was calculated as the percentage of knee flexor peak torque relative to knee extensor peak torque.
Testing was performed at 60°/s angular velocity, a standard velocity for evaluating maximal voluntary muscle contraction.
Participants were seated with their hips and knees at approximately 90° flexion. The dominant leg was tested and stabilized using straps at the trunk, thigh, and lower leg. Gravity correction was applied prior to testing.
Following a 5-minute warm-up and 3 submaximal practice repetitions, each participant performed 3 maximal concentric repetitions of knee extension and flexion.
The dominant leg was defined as the preferred leg for kicking, confirmed via observation of a standardized ball-kicking task.
Measured: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Change from Baseline in the muscle oscillation frequency at 6 weeks
Evaluated using the MyotonPRO® handheld myotonometer (Myoton AS, Estonia), a non-invasive digital palpation device validated for muscle and tendon assessment.
Muscles assessed on the dominant leg included:
Muscles: Vastus Medialis (VM), Vastus Lateralis (VL), Semitendinosus (ST), Gastrocnemius Medialis (GM)
Participants were positioned supine or prone, depending on the target tissue. The device probe was applied perpendicularly to the skin over the anatomical landmark recommended by the manufacturer.
Each site was measured three times, and the mean value was used for analysis. Measurements were repeated if the coefficient of variation exceeded 10%.
Measured: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Change from Baseline in the stiffness at 6 weeks
Evaluated using the MyotonPRO® handheld myotonometer (Myoton AS, Estonia), a non-invasive digital palpation device validated for muscle and tendon assessment.
Muscles and tendons assessed on the dominant leg included:
Muscles: Vastus Medialis (VM), Vastus Lateralis (VL), Semitendinosus (ST), Gastrocnemius Medialis (GM) Tendons: Patellar Tendon (PT), Achilles Tendon (AT)
Participants were positioned supine or prone, depending on the target tissue. The device probe was applied perpendicularly to the skin over the anatomical landmark recommended by the manufacturer.
Each site was measured three times, and the mean value was used for analysis. Measurements were repeated if the coefficient of variation exceeded 10%.
Measured: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 May 2025
- Study start6 Jan 2025
- Primary completion28 Mar 2025
- Study completion31 Mar 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Americas - Chili
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Maximiliano Torres-Banduc, University of Americas - Chili
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06987344
- Sponsor's protocol ID
- 2025015
- Status last verified
- May 2025
- First submitted
- 15 May 2025
- Last updated
- 29 May 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Will be reported or made available upon reasonable request.
Study at a glance
From the registry record, last updated by the sponsor on 29 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Field-based Closed Kinetic Chain Training With Progressive Eccentric Time Under Tension: Effects on Knee Strength and Lower Limb Viscoelasticity in Soccer Players: a Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT06987344
- Acronym / sponsor ID
- 2025015
- Conditions
- Healthy
- Keywords
- Exercise therapy, Muscle strength, Lower extremity, Tendons
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- University of Americas - ChiliUniversity, hospital or other
- Study start
- 6 Jan 2025 (actual)
- Primary completion
- 28 Mar 2025 (actual)
- Study completion
- 31 Mar 2025 (actual)
- First posted
- 23 May 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.
The goal of this study is to learn whether a 6-week lower-body training program using closed kinetic chain (CKC) exercises with slow, controlled movements (called "eccentric time under tension") can improve leg muscle strength and muscle-tendon viscoelastic properties in male university soccer players.
The Main Questions Are:
- Does this type of training improve knee strength?
- Does it change the way muscles and tendons respond to movement or pressure?
What Will Participants Do?
- Join one of two groups: one does the CKC training program, the other continues regular soccer training
- Train twice a week for 6 weeks
- Have their leg strength tested using special equipment
- Have their muscle and tendon properties measured with a handheld device
Detailed description
This randomized controlled trial investigated the effects of a 6-week, field-based closed kinetic chain (CKC) exercise program with progressively increased eccentric time under tension (TUT) on isokinetic knee performance and lower limb muscle-tendon viscoelastic properties in male university soccer players.
A total of 24 healthy participants were randomly assigned (1:1) to either an intervention group performing supervised CKC exercises or an active control group that maintained routine soccer training. The CKC training was performed twice per week and included progressive increases in eccentric phase duration and external loading. Training volume was quantified using both mechanical load and eccentric TUT. Each session lasted approximately 35 minutes and included a variety of multi-joint, bilateral and unilateral exercises performed on a soccer field.
Baseline and post-intervention assessments were conducted using:
Isokinetic dynamometry (Biodex System 3 Pro) to measure concentric peak torque, mean power, and agonist/antagonist ratio at 60°/s.
MyotonPRO handheld myotonometer to assess oscillation frequency and stiffness of specific lower limb muscles (VM, VL, ST, GM) and tendons (Achilles, patellar).
Muscle and tendon assessments were performed following standardized anatomical landmarks. To ensure data reliability, repeated trials were used and measurements with high variability were repeated. Pre-testing familiarization was implemented to reduce learning effects.
The statistical approach included a two-way repeated measures ANOVA to compare group (CKC vs. control) and time (pre vs. post) effects. Holm-Sidak post hoc tests were applied when appropriate, and effect sizes were interpreted using eta squared (η²). All data analyses were conducted using JASP software (v0.18.3).
The protocol was reviewed and approved by an institutional ethics committee , and written informed consent was obtained from all participants. No serious adverse events were reported, and dropout was minimal (n = 4). No dietary interventions were applied; however, participants were instructed to maintain consistent routines throughout.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Active Control Group | Active comparator | Other: Regular soccer training routinesMaintained their customary daily activities and regular soccer training routines: Trained three times a week, two days were dedicated to functional and tactical on-field training, while the third day was reserved for a two-hour gym session focused on flexibility, muscular strength, and endurance development. |
| Closed Kinetic Chain Group | Experimental | Other: Field-based closed kinetic chain exercise with progressively increased time under tension, Other: Regular soccer training routinesIn addition to the same activities as the active cotrol group, participants performed five to seven different closed kinetic chain drills during the two days of field-based training, completing two to three sets per drill and eight to fourteen repetitions per set. The training volume underwent gradual increments over the course of every week. The total training volume for externally loaded CKC exercises was calculated by summing sets × repetitions × load (kg), yielding a cumulative volume of approximately 10,863 kg over 12 sessions. For exercises involving bodyweight or elastic resistance, training volume was estimated using time under tension (TUT), computed as the product of repetitions and eccentric phase duration. The cumulative TUT throughout the 6-week protocol amounted to 9,300 seconds (155 minutes) of eccentric loading. |
Who may qualify
- Ages
- 18 to 25 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Absence of any medical conditions that could compromise their ability to participate.
- Active membership in their university's soccer team for a minimum of one year.
Key exclusion criteria (2 listed)
- Musculoskeletal injuries reported in the two months prior to the start of the study.
- Surgical interventions involving the lower limbs within the past year.
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 |
|---|---|---|
| Field-based closed kinetic chain exercise with progressively increased time under tensionThis intervention is uniquely characterized by the integration of field-based closed kinetic chain (CKC) exercises with a systematically increased eccentric time under tension (TUT), specifically tailored for university-level soccer players. Unlike conventional strength training protocols, which are often gym-based and rely on traditional resistance machines or free weights, this program emphasizes functional, sport-specific movement patterns performed on the field, enhancing ecological validity and transfer to soccer performance. | Other | Closed Kinetic Chain Group |
| Regular soccer training routinesTrained three times a week: two days were dedicated to functional and tactical on-field training, while the third day was reserved for a two-hour gym session focused on flexibility, muscular strength, and endurance development. | Other | Active Control Group, Closed Kinetic Chain Group |
Primary outcome
Change from baseline in the rotational peak torque relative to body mass at 6 weeks
Time frame: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Assessed using a Biodex® System 3 Pro isokinetic dynamometer (Shirley, NY, USA), with a validated accuracy of ±1%. Testing was performed at 60°/s angular velocity, a standard velocity for evaluating maximal voluntary muscle contraction. Participants were seated with their hips and knees at approximately 90° flexion. The dominant leg was tested and stabilized using straps at the trunk, thigh, and lower leg. Gravity correction was applied prior to testing. Following a 5-minute warm-up and 3 submaximal practice repetitions, each participant performed 3 maximal concentric repetitions of knee extension and flexion. The dominant leg was defined as the preferred leg for kicking, confirmed via observation of a standardized ball-kicking task.
Change from baseline in the rotational mean power at 6 weeks
Time frame: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Assessed using a Biodex® System 3 Pro isokinetic dynamometer (Shirley, NY, USA), with a validated accuracy of ±1%. Testing was performed at 60°/s angular velocity, a standard velocity for evaluating maximal voluntary muscle contraction. Participants were seated with their hips and knees at approximately 90° flexion. The dominant leg was tested and stabilized using straps at the trunk, thigh, and lower leg. Gravity correction was applied prior to testing. Following a 5-minute warm-up and 3 submaximal practice repetitions, each participant performed 3 maximal concentric repetitions of knee extension and flexion. The dominant leg was defined as the preferred leg for kicking, confirmed via observation of a standardized ball-kicking task.
3 secondary outcomes
Change from baseline in the agonist/antagonist strength ratio at 6 weeks
Time frame: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Change from Baseline in the muscle oscillation frequency at 6 weeks
Time frame: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
Change from Baseline in the stiffness at 6 weeks
Time frame: From enrollment to the end of closed kinetic chain training protocol at 6 weeks
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 29 May 2025.
- Individual participant dataSharing planned: No. Will be reported or made available upon reasonable 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?
A study testing Field-based closed kinetic chain exercise with progressively increased time under tension and Regular soccer training routines in people with Healthy, run by University of Americas - Chili 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 2 inclusion and 2 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 29 May 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 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?
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?
Change from baseline in the rotational peak torque relative to body mass at 6 weeks (time frame: From enrollment to the end of closed kinetic chain training protocol at 6 weeks). 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 29 May 2025.