Acute Muscle Damage Following Resistance ExerciseNCT07431879
Acute Muscle Damage After Eccentric Quasi-Isometric Exercise of the Elbow Flexors
A study testing Eccentric Quasi-Isometric Exercise and Traditional Eccentric Exercise in people with Acute Muscle Damage Following Resistance Exercise, run by Chinese Culture University at 1 site in Taiwan.
Trial summary
This study compared the acute muscle damage responses of the elbow flexor muscles following two types of resistance exercise: eccentric quasi-isometric (EQI) exercise and traditional eccentric (ECC) exercise. Read more about this study
- Who is it for?
- Ages 20 to 30 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Acute Muscle Damage Following Resistance Exercise
- What is being tested?
- Eccentric Quasi-Isometric Exercise and Traditional Eccentric Exercise
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 30 participants
- Where
- 1 siteTaiwan
- Study dates
- 1 Aug 2020to 1 Aug 2021
- 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 20 to 30 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy young men
- Age between 20 and 30 years
- No participation in any regular exercise training programs during the previous 12 months
- No history of cardiovascular disease, diabetes mellitus, liver disease, respiratory disorders, neuromuscular disease, or musculoskeletal disorders
- No long-term use of chronic prescription medications
- No history of dizziness, chest discomfort, or falls during physical activity
- Not previously diagnosed by a physician as unsuitable for exercise
Who cannot join
- History of upper limb musculoskeletal, joint, or bone injuries
- Inability to independently perform activities of daily living
- Presence of cardiovascular, metabolic, respiratory, neuromuscular, or musculoskeletal disorders
- Requirement for assistive devices for ambulation in daily life
- Previous medical diagnosis indicating unsuitability for exercise participation
- Presence of acute illness at the time of enrollment
- History of major surgery within the past 12 months
- Severe physical injury that could impair exercise performance or daily activities
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Acute Muscle Damage Responses in Elbow Flexors Following Eccentric Quasi-isometric Exercise
This study compared the acute muscle damage responses of the elbow flexor muscles following two types of resistance exercise: eccentric quasi-isometric (EQI) exercise and traditional eccentric (ECC) exercise. Thirty healthy young men were randomly assigned to perform either EQI or ECC using a dumbbell elbow flexion exercise. Both groups exercised with the same relative external load and performed the exercise to voluntary fatigue.
Muscle function, muscle soreness, and blood markers related to muscle damage were assessed before exercise, immediately after exercise, and over a 7-day recovery period. The purpose of this study was to examine whether EQI exercise, which involves a prolonged isometric phase followed by a very slow eccentric action, induces different levels of acute muscle damage and recovery compared with traditional eccentric exercise.
Read the detailed description
Eccentric resistance exercise is widely used in strength training but is often associated with substantial exercise-induced muscle damage, resulting in strength loss, muscle soreness, swelling, and prolonged recovery. Eccentric quasi-isometric (EQI) exercise is a recently proposed contraction mode that combines a sustained isometric hold with a subsequent extremely slow eccentric lengthening under continuous voluntary resistance. This contraction pattern results in prolonged time under tension while avoiding rapid lengthening or abrupt force spikes.
In this randomized interventional study, thirty healthy young men with no recent resistance training experience were randomly assigned to perform either EQI or traditional eccentric (ECC) exercise of the elbow flexors. Participants performed unilateral dumbbell elbow flexion exercise at 70% of their one-repetition maximum. The EQI group completed five sets of single repetitions consisting of an initial isometric hold at 90 degrees of elbow flexion until task failure, followed by very slow eccentric lengthening to full elbow extension. The ECC group performed five sets of repeated eccentric-only elbow flexion exercises at a controlled tempo until failure. Rest intervals were standardized between sets.
Muscle damage and recovery were evaluated using multiple functional and biochemical indicators, including maximal voluntary isometric contraction torque, elbow joint range of motion, upper arm circumference, pressure pain threshold, and circulating concentrations of creatine kinase and myoglobin. Measurements were obtained before exercise, immediately after exercise, and at 1, 2, 3, and 7 days following the exercise bout.
The primary objective of this study was to compare the acute muscle damage responses and recovery profiles of the elbow flexors following EQI and ECC exercise when performed to voluntary fatigue at the same relative external load.
- Being tested
- Eccentric Quasi-Isometric Exercise, Traditional Eccentric Exercise
- Keywords
- Resistance exercise, Exhaustive exercise, Muscle fatigue, Mechanical tension, Contraction characteristics
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Eccentric Quasi-Isometric ExerciseBehavioural
Eccentric quasi-isometric (EQI) exercise of the elbow flexors was performed using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. Each repetition began with a sustained isometric contraction at 90 degrees of elbow flexion until task failure, followed immediately by a very slow eccentric lengthening to full elbow extension while participants continued to resist the load. One repetition was defined as the continuous task from the onset of the isometric hold to full elbow extension. Participants completed five sets of one repetition with 90 seconds of rest between sets. All repetitions were performed to voluntary fatigue under supervision.
Traditional Eccentric ExerciseBehavioural
Traditional eccentric-only exercise of the elbow flexors was performed using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. From a starting position of 90 degrees of elbow flexion, participants repeatedly lowered the dumbbell through the full range of motion using controlled eccentric contractions at a cadence of approximately 2.5 seconds per repetition, guided by a metronome. Each set was performed to voluntary failure, and a total of five sets were completed with 90 seconds of rest between sets.
| Study group | Role | What they receive |
|---|---|---|
| eccentric quasi-isometric (EQI) | Experimental | Participants assigned to this arm performed eccentric quasi-isometric (EQI) exercise of the elbow flexors using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. Each repetition began with a sustained isometric hold at 90 degrees of elbow flexion until task failure, followed immediately by a very slow eccentric lengthening to full elbow extension while participants continued to resist the load. Participants completed five sets of one repetition, with 90 seconds of rest between sets. All repetitions were performed to voluntary fatigue under supervision. Receives: Behavioral: Eccentric Quasi-Isometric Exercise |
| Traditional Eccentric Exercise (ECC) | Active comparator | Participants assigned to this arm performed traditional eccentric-only exercise of the elbow flexors using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. From a starting position of 90 degrees of elbow flexion, participants repeatedly lowered the dumbbell through the full range of motion using controlled eccentric contractions at a cadence of approximately 2.5 seconds per repetition, guided by a metronome. Each set was performed to voluntary failure, and a total of five sets were completed with 90 seconds of rest between sets. Receives: Behavioral: Traditional Eccentric Exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maximal Voluntary Isometric Contraction (MVC) Torque
Maximal voluntary isometric contraction (MVC) torque of the elbow flexors was assessed using an isokinetic dynamometer with the elbow positioned at 90 degrees of flexion. Participants performed three maximal 3-second isometric contractions with standardized verbal encouragement. The highest torque value obtained across trials was used for analysis as an indicator of muscle function and strength loss following exercise.
Measured: Baseline (Day 0) and Days 1, 2, 3, and 7
Secondary outcomes (6)
Elbow Joint Range of Motion (ROM)
Elbow joint range of motion (ROM) was assessed using a manual goniometer by measuring the relaxed elbow joint angle and the fully flexed elbow joint angle. ROM was calculated as the difference between these two angles and used as an indicator of joint mobility restriction following exercise-induced muscle damage.
Measured: Baseline (Day 0) and Days 1, 2, 3, and 7
Upper Arm Circumference (CIR)
Upper arm circumference (CIR) was measured at the midpoint between the acromion and the lateral epicondyle with the arm relaxed and extended. Circumference measurements were used as an indirect indicator of muscle swelling following exercise.
Measured: Baseline (Day 0) and Days 1, 2, 3, and 7
Pressure Pain Threshold (PPT)
Pressure pain threshold (PPT) of the elbow flexors was assessed using a digital pressure algometer at the proximal, middle, and distal regions of the biceps brachii. PPT values were used to quantify changes in pain sensitivity following exercise.
Measured: Baseline (Day 0) and Days 1, 2, 3, and 7
Plasma Creatine Kinase (CK)
Plasma creatine kinase (CK) activity was measured from venous blood samples using an automated clinical chemistry analyzer. CK concentration was used as a biochemical marker of muscle membrane disruption following exercise.
Measured: Baseline (Day 0) and Days 1, 2, 3, and 7
Plasma Myoglobin (Mb)
Plasma myoglobin (Mb) concentration was determined from venous blood samples using a chemiluminescent immunoassay. Myoglobin levels were used as a biochemical indicator of muscle damage following exercise.
Measured: Baseline (Day 0) and Days 1, 2, 3, and 7
Time Under Tension (TUT)
Time under tension (TUT) was recorded during the exercise session as the total duration of muscle contraction. TUT was measured for each exercise set and used to characterize differences in contraction duration between exercise conditions.
Measured: Day 1
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Feb 2026
- Study start1 Aug 2020
- Primary completion1 Aug 2021
- Study completion1 Aug 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute Muscle Damage Following Resistance 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
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study used a parallel-group randomized design. Participants were randomly assigned to one of two intervention arms (eccentric quasi-isometric exercise or traditional eccentric exercise) and completed a single supervised exercise session. All outcomes were assessed repeatedly within the same participants at predefined time points before and after the intervention.
- Masking
- None (open label)
- Enrolment
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- Chinese Culture University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, TSUNG-LIN CHIANG, Chinese Culture University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07431879
- Sponsor's protocol ID
- PCCU
- Other IDs
- MOST 109-2410-H-034-041
- Status last verified
- Feb 2026
- First submitted
- 10 Feb 2026
- Last updated
- 25 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 25 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Muscle Damage Responses in Elbow Flexors Following Eccentric Quasi-isometric Exercise
- ClinicalTrials.gov ID
- NCT07431879
- Acronym / sponsor ID
- PCCU
- Keywords
- Resistance exercise, Exhaustive exercise, Muscle fatigue, Mechanical tension, Contraction characteristics
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- Chinese Culture UniversityUniversity, hospital or other
- Study start
- 1 Aug 2020 (actual)
- Primary completion
- 1 Aug 2021 (actual)
- Study completion
- 1 Aug 2021 (actual)
- First posted
- 25 Feb 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 compared the acute muscle damage responses of the elbow flexor muscles following two types of resistance exercise: eccentric quasi-isometric (EQI) exercise and traditional eccentric (ECC) exercise. Thirty healthy young men were randomly assigned to perform either EQI or ECC using a dumbbell elbow flexion exercise. Both groups exercised with the same relative external load and performed the exercise to voluntary fatigue.
Muscle function, muscle soreness, and blood markers related to muscle damage were assessed before exercise, immediately after exercise, and over a 7-day recovery period. The purpose of this study was to examine whether EQI exercise, which involves a prolonged isometric phase followed by a very slow eccentric action, induces different levels of acute muscle damage and recovery compared with traditional eccentric exercise.
Detailed description
Eccentric resistance exercise is widely used in strength training but is often associated with substantial exercise-induced muscle damage, resulting in strength loss, muscle soreness, swelling, and prolonged recovery. Eccentric quasi-isometric (EQI) exercise is a recently proposed contraction mode that combines a sustained isometric hold with a subsequent extremely slow eccentric lengthening under continuous voluntary resistance. This contraction pattern results in prolonged time under tension while avoiding rapid lengthening or abrupt force spikes.
In this randomized interventional study, thirty healthy young men with no recent resistance training experience were randomly assigned to perform either EQI or traditional eccentric (ECC) exercise of the elbow flexors. Participants performed unilateral dumbbell elbow flexion exercise at 70% of their one-repetition maximum. The EQI group completed five sets of single repetitions consisting of an initial isometric hold at 90 degrees of elbow flexion until task failure, followed by very slow eccentric lengthening to full elbow extension. The ECC group performed five sets of repeated eccentric-only elbow flexion exercises at a controlled tempo until failure. Rest intervals were standardized between sets.
Muscle damage and recovery were evaluated using multiple functional and biochemical indicators, including maximal voluntary isometric contraction torque, elbow joint range of motion, upper arm circumference, pressure pain threshold, and circulating concentrations of creatine kinase and myoglobin. Measurements were obtained before exercise, immediately after exercise, and at 1, 2, 3, and 7 days following the exercise bout.
The primary objective of this study was to compare the acute muscle damage responses and recovery profiles of the elbow flexors following EQI and ECC exercise when performed to voluntary fatigue at the same relative external load.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- This study used a parallel-group randomized design. Participants were randomly assigned to one of two intervention arms (eccentric quasi-isometric exercise or traditional eccentric exercise) and completed a single supervised exercise session. All outcomes were assessed repeatedly within the same participants at predefined time points before and after the intervention.
| Arm | Type | Receives |
|---|---|---|
| eccentric quasi-isometric (EQI) | Experimental | Behavioral: Eccentric Quasi-Isometric ExerciseParticipants assigned to this arm performed eccentric quasi-isometric (EQI) exercise of the elbow flexors using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. Each repetition began with a sustained isometric hold at 90 degrees of elbow flexion until task failure, followed immediately by a very slow eccentric lengthening to full elbow extension while participants continued to resist the load. Participants completed five sets of one repetition, with 90 seconds of rest between sets. All repetitions were performed to voluntary fatigue under supervision. |
| Traditional Eccentric Exercise (ECC) | Active comparator | Behavioral: Traditional Eccentric ExerciseParticipants assigned to this arm performed traditional eccentric-only exercise of the elbow flexors using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. From a starting position of 90 degrees of elbow flexion, participants repeatedly lowered the dumbbell through the full range of motion using controlled eccentric contractions at a cadence of approximately 2.5 seconds per repetition, guided by a metronome. Each set was performed to voluntary failure, and a total of five sets were completed with 90 seconds of rest between sets. |
Who may qualify
- Ages
- 20 to 30 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Healthy young men
- Age between 20 and 30 years
- No participation in any regular exercise training programs during the previous 12 months
- No history of cardiovascular disease, diabetes mellitus, liver disease, respiratory disorders, neuromuscular disease, or musculoskeletal disorders
- No long-term use of chronic prescription medications
Key exclusion criteria (8 listed)
- History of upper limb musculoskeletal, joint, or bone injuries
- Inability to independently perform activities of daily living
- Presence of cardiovascular, metabolic, respiratory, neuromuscular, or musculoskeletal disorders
- Requirement for assistive devices for ambulation in daily life
- Previous medical diagnosis indicating unsuitability for exercise participation
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 |
|---|---|---|
| Eccentric Quasi-Isometric ExerciseEccentric quasi-isometric (EQI) exercise of the elbow flexors was performed using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. Each repetition began with a sustained isometric contraction at 90 degrees of elbow flexion until task failure, followed immediately by a very slow eccentric lengthening to full elbow extension while participants continued to resist the load. One repetition was defined as the continuous task from the onset of the isometric hold to full elbow extension. Participants completed five sets of one repetition with 90 seconds of rest between sets. All repetitions were performed to voluntary fatigue under supervision. | Behavioural | eccentric quasi-isometric (EQI) |
| Traditional Eccentric ExerciseTraditional eccentric-only exercise of the elbow flexors was performed using a unilateral dumbbell preacher curl. The external load was set at 70% of each participant's one-repetition maximum. From a starting position of 90 degrees of elbow flexion, participants repeatedly lowered the dumbbell through the full range of motion using controlled eccentric contractions at a cadence of approximately 2.5 seconds per repetition, guided by a metronome. Each set was performed to voluntary failure, and a total of five sets were completed with 90 seconds of rest between sets. | Behavioural | Traditional Eccentric Exercise (ECC) |
Primary outcome
Maximal Voluntary Isometric Contraction (MVC) Torque
Time frame: Baseline (Day 0) and Days 1, 2, 3, and 7
Maximal voluntary isometric contraction (MVC) torque of the elbow flexors was assessed using an isokinetic dynamometer with the elbow positioned at 90 degrees of flexion. Participants performed three maximal 3-second isometric contractions with standardized verbal encouragement. The highest torque value obtained across trials was used for analysis as an indicator of muscle function and strength loss following exercise.
6 secondary outcomes
Elbow Joint Range of Motion (ROM)
Time frame: Baseline (Day 0) and Days 1, 2, 3, and 7
Upper Arm Circumference (CIR)
Time frame: Baseline (Day 0) and Days 1, 2, 3, and 7
Pressure Pain Threshold (PPT)
Time frame: Baseline (Day 0) and Days 1, 2, 3, and 7
Plasma Creatine Kinase (CK)
Time frame: Baseline (Day 0) and Days 1, 2, 3, and 7
Plasma Myoglobin (Mb)
Time frame: Baseline (Day 0) and Days 1, 2, 3, and 7
Time Under Tension (TUT)
Time frame: Day 1
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 25 Feb 2026.
- Individual participant dataSharing planned: No
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 Eccentric Quasi-Isometric Exercise and Traditional Eccentric Exercise in people with Acute Muscle Damage Following Resistance Exercise, run by Chinese Culture University at 1 site in Taiwan.
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 7 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: finished, as of the sponsor's last update on 25 Feb 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 Taiwan. 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?
Maximal Voluntary Isometric Contraction (MVC) Torque (time frame: Baseline (Day 0) and Days 1, 2, 3, and 7). 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 25 Feb 2026.