Eccentric ExerciseMUSOX-EXNCT07548333
Metabolic, Respiratory, and Muscle Oxygenation Responses to Sub-maximal Eccentric and Concentric Isokinetic Exercise to Exhaustion
A study testing Sub maximal concentric exercise and Sub maximal eccentric exercise in people with Eccentric Exercise and Isokinetic Test, run by National and Kapodistrian University of Athens at 1 site in Greece.
Trial summary
This study aims to measure and compare the metabolic response during sub maximal eccentric and concentric isokinetic exercise performed to exhaustion. Fourteen healthy female participants in the early phase of the menstrual cycle will perform concentric exercise with one lower limb and eccentric exercise with the… Read more about this study
- Who is it for?
- Ages 18 to 30 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Eccentric Exercise, Isokinetic Test
- What is being tested?
- Sub maximal concentric exercise and Sub maximal eccentric exercise
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 14 participants
- Where
- 1 siteGreece
- Study dates
- 12 Sep 2025to 28 Mar 2026
- 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 30 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Physically active young females
- No experience in activities involving significant resistance exercise components
- No experience in muscle-damaging activities for at least 6-months prior to the study.
Who cannot join
- Any musculoskeletal injuries in the lower limbs within the past 6 months
- Use of contraceptives
- Irregular menstrual cycles
- Smoking
- Consumption of protein and antioxidant supplements
- Potential inflammatory conditions.
Trial locations and contacts
1 site in 1 country.
Greece1 site
School of Physical Education and Sport Science
Athens, Attica, 17234
About this study
Official title: Responses to Sub-maximal Eccentric and Concentric Isokinetic Exercise to Exhaustion
This study aims to measure and compare the metabolic response during sub maximal eccentric and concentric isokinetic exercise performed to exhaustion. Fourteen healthy female participants in the early phase of the menstrual cycle will perform concentric exercise with one lower limb and eccentric exercise with the contralateral limb. The assignment of exercise mode to limb and the order of testing will be randomized. The exercise protocol will consist of repeated knee extensor contractions on an isokinetic dynamometer for 10 minutes at 40% of maximal torque, followed by exercise at 70% of maximal torque until exhaustion. Oxygen consumption and respiratory quotient and will be measured continuously throughout exercise using open-circuit spirometry. Muscle oxygenation will be measured also continuously using near infrared spectroscopy. Lactate and pH concentration will be measured at frequent time points during the exercise to exhaustion.
Read the detailed description
The purpose of this study is to investigate and compare the metabolic responses during sub maximal eccentric and concentric isokinetic exercise performed to exhaustion. Eccentric and concentric muscle actions differ in their physiological and metabolic demands, but their effects on respiratory parameters during fatiguing isokinetic exercise are not fully understood. This study is designed to examine whether these two contraction modes produce distinct metabolic responses under controlled exercise conditions.
Fourteen healthy female participants will be recruited and tested during the early phase of their menstrual cycle in order to reduce the possible influence of hormonal variation on physiological responses. A within-subject design will be used, with each participant completing both exercise conditions. One lower limb will perform concentric exercise and the contralateral lower limb will perform eccentric exercise. The limb allocation and the order of the two exercise conditions will be randomized.
All exercise testing will be conducted on an isokinetic dynamometer. The protocol will involve repeated contractions of the knee extensor muscles. Each trial will begin with 10 minutes of exercise at 40% of maximal torque. Following this initial stage, the intensity will be increased to 70% of maximal torque and maintained until volitional exhaustion is reached.
Oxygen consumption and respiratory quotient will be measured continuously throughout the exercise bout using open-circuit spirometry. Continuous monitoring of gas exchange during exercise will allow evaluation of substrate utilization and metabolic responses associated with each mode of contraction. Muscle oxygenation will be measured also continuously using near infrared spectroscopy. Lactate and pH concentration will be measured at frequent time points during the exercise to exhaustion.
The study is expected to provide further insight into the metabolic and respiratory differences between eccentric and concentric exercise performed under submaximal but fatiguing isokinetic conditions. The findings may have implications for exercise testing, training prescription, and rehabilitation settings in which eccentric and concentric muscle actions are used for different physiological purposes.
- Conditions
- Eccentric Exercise, Isokinetic Test
- Being tested
- Sub maximal concentric exercise, Sub maximal eccentric exercise
- Keywords
- Eccentric exercise, Concentric exercise, oxygen consumption, muscle oxygenation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Sub maximal concentric exerciseOther
Based on their maximal performance on isokinetic concentric muscle contractions, participants performed sub-maximal concentric knee extensor exercise on an isokinetic dynamometer. The protocol consists of 10 minutes exercise at 40% of maximal torque followed by exercise at 70% of maximal torque until exhaustion. The exercise protocol was continuous, which mean that no interval was adopted at any stage of the protocol.
Sub maximal eccentric exerciseOther
Based on their maximal performance on isokinetic eccentric muscle contractions, participants performed sub-maximal concentric knee extensor exercise on an isokinetic dynamometer. The protocol consists of 10 minutes exercise at 40% of maximal torque followed by exercise at 70% of maximal torque until exhaustion. The exercise protocol was continuous, which mean that no interval was adopted at any stage of the protocol.
| Study group | Role | What they receive |
|---|---|---|
| Isokinetic concentric exercise | Experimental | The concentric isokinetic exercise will be consisted of 10 minutes at 40% of maximal torque followed by repetitions at an intensity of 70% of maximal torque until exhaustion. Receives: Other: Sub maximal concentric exercise |
| Isokinetic eccentric exercise | Experimental | The eccentric isokinetic exercise will be consisted of 10 minutes at 40% of maximal torque followed by repetitions at an intensity of 70% of maximal torque until exhaustion. Receives: Other: Sub maximal eccentric exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Oxygen consumption
Oxygen consumption will be measured continuously using a open circuit chart during the whole duration of the isokinetic (either eccentric or concentric) exercise.
Measured: From the first intervention to the last intervention 2 weeks
Muscle oxygenation
Muscle oxygenation will be measured continuously using a open circuit chart during the whole duration of the isokinetic (either eccentric or concentric) exercise.
Measured: From the first intervention to the last intervention 2 weeks
Duration of the isokinetic exercise
The whole duration of both isokinetic concentric and eccentric exercise will be recored
Measured: From the first intervention to the last intervention 2 weeks
Secondary outcomes (3)
Respiratory quotient
Respiratory quotient will be measured continuously using a open circuit chart during the whole duration of the isokinetic (either eccentric or concentric) exercise.
Measured: From the first intervention to the last intervention 2 weeks
Lactate concentration
Blood from fingertips will be collected periodically during the isokinetic exercise for both types of muscle contraction (concentric and eccentric)
Measured: From the first intervention to the last intervention 2 weeks
pH measurement
Blood will be collected periodically during the isokinetic exercise for both types of muscle contraction (concentric and eccentric)
Measured: From the first intervention to the last intervention 2 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2026
- Study start12 Sep 2025
- Primary completion18 Jan 2026
- Study completion28 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Eccentric ExerciseStudies of the same condition, open and under way.
- More trials run by National and Kapodistrian University of AthensThe sponsor's other registered studies.
- 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
- Crossover
- Model description
- Each participant will complete both exercise conditions. One lower limb will perform concentric exercise and the contralateral lower limb will perform eccentric exercise. The limb allocation and the order of the two exercise conditions will be randomized.
- Masking
- None (open label)
- Enrolment
- 14 participants (actual)
Sponsor and investigators
- Lead sponsor
- National and Kapodistrian University of Athens
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Vassilis Paschalis, National and Kapodistrian University of Athens
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07548333
- Sponsor's protocol ID
- 1424/21-11-2022
- Acronym
- MUSOX-EX
- Status last verified
- Apr 2026
- First submitted
- 17 Apr 2026
- Last updated
- 30 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be made publicly available.
Study at a glance
From the registry record, last updated by the sponsor on 30 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Responses to Sub-maximal Eccentric and Concentric Isokinetic Exercise to Exhaustion
- ClinicalTrials.gov ID
- NCT07548333
- Acronym / sponsor ID
- MUSOX-EX / 1424/21-11-2022
- Conditions
- Eccentric Exercise, Isokinetic Test
- Keywords
- Eccentric exercise, Concentric exercise, oxygen consumption, muscle oxygenation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 14 participants (actual)
- Lead sponsor
- National and Kapodistrian University of AthensUniversity, hospital or other
- Study start
- 12 Sep 2025 (actual)
- Primary completion
- 18 Jan 2026 (actual)
- Study completion
- 28 Mar 2026 (actual)
- First posted
- 23 Apr 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.
This study aims to measure and compare the metabolic response during sub maximal eccentric and concentric isokinetic exercise performed to exhaustion. Fourteen healthy female participants in the early phase of the menstrual cycle will perform concentric exercise with one lower limb and eccentric exercise with the contralateral limb. The assignment of exercise mode to limb and the order of testing will be randomized. The exercise protocol will consist of repeated knee extensor contractions on an isokinetic dynamometer for 10 minutes at 40% of maximal torque, followed by exercise at 70% of maximal torque until exhaustion. Oxygen consumption and respiratory quotient and will be measured continuously throughout exercise using open-circuit spirometry. Muscle oxygenation will be measured also continuously using near infrared spectroscopy. Lactate and pH concentration will be measured at frequent time points during the exercise to exhaustion.
Detailed description
The purpose of this study is to investigate and compare the metabolic responses during sub maximal eccentric and concentric isokinetic exercise performed to exhaustion. Eccentric and concentric muscle actions differ in their physiological and metabolic demands, but their effects on respiratory parameters during fatiguing isokinetic exercise are not fully understood. This study is designed to examine whether these two contraction modes produce distinct metabolic responses under controlled exercise conditions.
Fourteen healthy female participants will be recruited and tested during the early phase of their menstrual cycle in order to reduce the possible influence of hormonal variation on physiological responses. A within-subject design will be used, with each participant completing both exercise conditions. One lower limb will perform concentric exercise and the contralateral lower limb will perform eccentric exercise. The limb allocation and the order of the two exercise conditions will be randomized.
All exercise testing will be conducted on an isokinetic dynamometer. The protocol will involve repeated contractions of the knee extensor muscles. Each trial will begin with 10 minutes of exercise at 40% of maximal torque. Following this initial stage, the intensity will be increased to 70% of maximal torque and maintained until volitional exhaustion is reached.
Oxygen consumption and respiratory quotient will be measured continuously throughout the exercise bout using open-circuit spirometry. Continuous monitoring of gas exchange during exercise will allow evaluation of substrate utilization and metabolic responses associated with each mode of contraction. Muscle oxygenation will be measured also continuously using near infrared spectroscopy. Lactate and pH concentration will be measured at frequent time points during the exercise to exhaustion.
The study is expected to provide further insight into the metabolic and respiratory differences between eccentric and concentric exercise performed under submaximal but fatiguing isokinetic conditions. The findings may have implications for exercise testing, training prescription, and rehabilitation settings in which eccentric and concentric muscle actions are used for different physiological purposes.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Each participant will complete both exercise conditions. One lower limb will perform concentric exercise and the contralateral lower limb will perform eccentric exercise. The limb allocation and the order of the two exercise conditions will be randomized.
| Arm | Type | Receives |
|---|---|---|
| Isokinetic concentric exercise | Experimental | Other: Sub maximal concentric exerciseThe concentric isokinetic exercise will be consisted of 10 minutes at 40% of maximal torque followed by repetitions at an intensity of 70% of maximal torque until exhaustion. |
| Isokinetic eccentric exercise | Experimental | Other: Sub maximal eccentric exerciseThe eccentric isokinetic exercise will be consisted of 10 minutes at 40% of maximal torque followed by repetitions at an intensity of 70% of maximal torque until exhaustion. |
Who may qualify
- Ages
- 18 to 30 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Physically active young females
- No experience in activities involving significant resistance exercise components
- No experience in muscle-damaging activities for at least 6-months prior to the study.
Key exclusion criteria (6 listed)
- Any musculoskeletal injuries in the lower limbs within the past 6 months
- Use of contraceptives
- Irregular menstrual cycles
- Smoking
- Consumption of protein and antioxidant supplements
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 |
|---|---|---|
| Sub maximal concentric exerciseBased on their maximal performance on isokinetic concentric muscle contractions, participants performed sub-maximal concentric knee extensor exercise on an isokinetic dynamometer. The protocol consists of 10 minutes exercise at 40% of maximal torque followed by exercise at 70% of maximal torque until exhaustion. The exercise protocol was continuous, which mean that no interval was adopted at any stage of the protocol. | Other | Isokinetic concentric exercise |
| Sub maximal eccentric exerciseBased on their maximal performance on isokinetic eccentric muscle contractions, participants performed sub-maximal concentric knee extensor exercise on an isokinetic dynamometer. The protocol consists of 10 minutes exercise at 40% of maximal torque followed by exercise at 70% of maximal torque until exhaustion. The exercise protocol was continuous, which mean that no interval was adopted at any stage of the protocol. | Other | Isokinetic eccentric exercise |
Primary outcome
Oxygen consumption
Time frame: From the first intervention to the last intervention 2 weeks
Oxygen consumption will be measured continuously using a open circuit chart during the whole duration of the isokinetic (either eccentric or concentric) exercise.
Muscle oxygenation
Time frame: From the first intervention to the last intervention 2 weeks
Muscle oxygenation will be measured continuously using a open circuit chart during the whole duration of the isokinetic (either eccentric or concentric) exercise.
Duration of the isokinetic exercise
Time frame: From the first intervention to the last intervention 2 weeks
The whole duration of both isokinetic concentric and eccentric exercise will be recored
3 secondary outcomes
Respiratory quotient
Time frame: From the first intervention to the last intervention 2 weeks
Lactate concentration
Time frame: From the first intervention to the last intervention 2 weeks
pH measurement
Time frame: From the first intervention to the last intervention 2 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 30 Apr 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be made publicly available.
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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 Sub maximal concentric exercise and Sub maximal eccentric exercise in people with Eccentric Exercise and Isokinetic Test, run by National and Kapodistrian University of Athens at 1 site in Greece.
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 3 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: finished, as of the sponsor's last update on 30 Apr 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 Greece. 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?
Oxygen consumption (time frame: From the first intervention to the last intervention 2 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?
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 30 Apr 2026.