Exercise-Induced FatigueNCT07742163
Muscle Oxygenation and Autonomic Recovery After Repeated Sprint in Competitive Soccer Players
A study testing 8 x 30 m Repeated Sprint Exercise in people with Exercise-Induced Fatigue, run by Pamukkale University at 1 site in Turkey (Türkiye).
Trial summary
This study evaluates the acute and short-term recovery responses to repeated sprint exercise in competitive male soccer players. Forty-eight licensed male soccer players complete an 8 × 30 m repeated sprint protocol under field conditions, with 25 seconds of active recovery between sprints. Read more about this study
- Who is it for?
- Ages 18 to 26 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Exercise-Induced Fatigue
- What is being tested?
- 8 x 30 m Repeated Sprint Exercise
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 48 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 2 Jun 2026to 28 Jun 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 26 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Licensed male competitive soccer player
- Age between 18 and 26 years
- Regularly participating in soccer training within a club
- Actively participating in official competitions
- At least 4 years of soccer training experience
- Physically able to complete the repeated sprint protocol
- No acute injury or illness on the measurement day
- Voluntary agreement to participate and provision of written informed consent
Who cannot join
- Acute lower-extremity injury
- Acute illness on the measurement day
- Inability to complete the repeated sprint protocol
- Missing data at any required measurement time point
- Failure to complete the 24-hour follow-up measurements
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Pamukkale University Sports Science Research Laboratory
Denizli, Pamukkale, 20000
About this study
Official title: Muscle Oxygenation and Autonomic Recovery After Repeated Sprint in Competitive Soccer Players: A NIRS-HRV-Based Field Study
This study evaluates the acute and short-term recovery responses to repeated sprint exercise in competitive male soccer players. Forty-eight licensed male soccer players complete an 8 × 30 m repeated sprint protocol under field conditions, with 25 seconds of active recovery between sprints.
The study examines several aspects of recovery. Muscle oxygenation is assessed using portable near-infrared spectroscopy sensors placed on the vastus lateralis and biceps femoris muscles. Cardiac autonomic recovery is evaluated using heart rate variability measurements obtained at baseline, 5 minutes, 30 minutes, and 24 hours after the repeated sprint protocol. Countermovement jump performance is measured before the protocol, 10 minutes after the protocol, and 24 hours later.
Sprint performance, blood lactate concentration, and perceived exertion are also recorded to characterize the physiological and performance demands of the repeated sprint protocol. The study aims to determine how muscle oxygenation, cardiac autonomic recovery, and neuromuscular performance change during the recovery period following repeated sprint exercise and whether these recovery indicators are associated with repeated sprint performance.
Read the detailed description
This study uses a single-group repeated-measures design to investigate muscle oxygenation, cardiac autonomic recovery, and neuromuscular performance responses following repeated sprint exercise in competitive male soccer players.
A total of 48 licensed male soccer players participate in the study. Participants regularly train and compete in soccer and have at least four years of soccer training experience.
During the measurement session, demographic and anthropometric characteristics are recorded first. Baseline measurements include heart rate variability, muscle oxygen saturation, blood lactate concentration, and countermovement jump performance. After a standardized 10-minute warm-up, participants complete an 8 × 30 m repeated sprint protocol. Each sprint is performed with maximal effort, and a 25-second active/light jogging recovery period is provided between sprints. Sprint times are recorded using an electronic timing gate system.
Muscle oxygenation is continuously assessed using portable near-infrared spectroscopy sensors placed on the vastus lateralis and biceps femoris muscles of the dominant leg. The evaluated muscle oxygenation variables include baseline muscle oxygen saturation, minimum muscle oxygen saturation, desaturation difference, 30-second reoxygenation muscle oxygen saturation, and reoxygenation rate.
Cardiac autonomic recovery is evaluated using heart rate variability derived from R-R interval recordings obtained with a Polar H10 chest strap. Five-minute HRV recordings are obtained at baseline, 5 minutes after the repeated sprint protocol, 30 minutes after the protocol, and 24 hours after the protocol. RMSSD and SDNN are used as the primary time-domain HRV parameters.
Neuromuscular performance is evaluated using countermovement jump height before the repeated sprint protocol, 10 minutes after the protocol, and 24 hours after the protocol. Blood lactate concentration is measured before the protocol and at 3 minutes after the protocol. Rating of perceived exertion is recorded after completion of the sprint protocol using the Borg CR10 scale.
The study is designed to characterize the time course of recovery following repeated sprint exercise and to examine relationships among sprint performance, muscle oxygenation, cardiac autonomic recovery, and neuromuscular performance. Because the study uses a single-group design without a control group, the findings are interpreted as recovery-related associations rather than evidence of causal effects.
- Conditions
- Exercise-Induced Fatigue
- Being tested
- 8 x 30 m Repeated Sprint Exercise
- Keywords
- Repeated Sprint, Muscle Oxygenation, Near-Infrared Spectroscopy, Heart Rate Variability, Countermovement Jump, Exercise Recovery, Soccer, Blood Lactate, Neuromuscular Performance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
8 x 30 m Repeated Sprint ExerciseOther
Participants perform eight 30-m maximal sprints under field conditions. A 25-second active recovery period consisting of light jogging is provided between consecutive sprints. Before the repeated sprint protocol, participants complete a standardized 10-minute warm-up consisting of low-intensity running, dynamic mobility exercises, and progressive acceleration runs.
| Study group | Role | What they receive |
|---|---|---|
| Repeated Sprint Exercise Group | Experimental | Participants complete an 8 × 30 m repeated sprint exercise protocol with maximal effort and 25 seconds of active recovery between sprints. Receives: Other: 8 x 30 m Repeated Sprint Exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Heart Rate Variability: RMSSD
RMSSD was calculated from 5-minute R-R interval recordings obtained using a Polar H10 chest strap and analyzed with Kubios HRV Standard software. RMSSD was expressed in milliseconds and used as an indicator of parasympathetic cardiac autonomic recovery.
Measured: Baseline, 5 minutes, 30 minutes, and 24 hours after the repeated sprint protocol.
Secondary outcomes (13)
Baseline Muscle Oxygen Saturation
Baseline muscle oxygen saturation (SmO2) was measured as a percentage using portable Moxy Monitor near-infrared spectroscopy sensors placed on the vastus lateralis and biceps femoris muscles of the dominant leg.
Measured: Immediately before the repeated sprint protocol.
Minimum Muscle Oxygen Saturation
The lowest muscle oxygen saturation (SmO2) value recorded during the repeated sprint protocol was determined separately for the vastus lateralis and biceps femoris muscles and expressed as a percentage.
Measured: During the 8 × 30 m repeated sprint protocol.
Muscle Oxygen Desaturation Difference
The muscle oxygen desaturation difference was calculated separately for the vastus lateralis and biceps femoris as baseline SmO2 minus minimum SmO2 and expressed in percentage points.
Measured: Baseline and during the 8 × 30 m repeated sprint protocol on Study Day 1.
Thirty-Second Muscle Reoxygenation
Muscle oxygen saturation was recorded 30 seconds after completion of the repeated sprint protocol using NIRS sensors placed on the vastus lateralis and biceps femoris muscles and expressed as a percentage.
Measured: 30 seconds after completion of the repeated sprint protocol.
Muscle Reoxygenation Rate
Muscle reoxygenation rate was calculated separately for the vastus lateralis and biceps femoris using the formula [(30-second reoxygenation SmO2 minus minimum SmO2) / 30] and expressed as percentage points per second.
Measured: During the first 30 seconds after completion of the repeated sprint protocol.
Countermovement Jump Height
Countermovement jump height was measured in centimeters using the My Jump 2 smartphone application. Three valid trials were performed at each time point, and the best valid trial was used for analysis.
Measured: Baseline, 10 minutes after the repeated sprint protocol, and 24 hours after the protocol.
Blood Lactate Concentration
Blood lactate concentration was measured in mmol/L using a Lactate Plus portable analyzer with capillary blood samples obtained from the fingertip.
Measured: Immediately before and 3 minutes after the repeated sprint protocol.
Rating of Perceived Exertion
Perceived exertion was assessed using the Borg CR10 scale ranging from 0 to 10, where higher values indicate greater perceived exercise intensity.
Measured: Immediately after completion of the repeated sprint protocol.
Sprint Time Across Repetitions
Completion time for each of the eight 30-m maximal sprints was recorded in seconds using a Witty wireless electronic timing gate system.
Measured: During each of the eight repetitions of the repeated sprint protocol on the test day.
Best Sprint Time
The fastest completion time among the eight 30-m maximal sprint repetitions was recorded in seconds.
Measured: During the 8 × 30 m repeated sprint protocol on the test day.
Mean Sprint Time
The arithmetic mean of the completion times recorded for the eight 30-m maximal sprint repetitions was calculated and expressed in seconds.
Measured: During the 8 × 30 m repeated sprint protocol on the test day.
Total Sprint Time
The sum of the completion times recorded for all eight 30-m maximal sprint repetitions was calculated and expressed in seconds.
Measured: During the 8 × 30 m repeated sprint protocol on the test day.
Sprint Performance Decrement
Sprint performance decrement was calculated as [(total sprint time / (best sprint time × number of sprints)) - 1] × 100. Higher values indicate a greater decline in repeated sprint performance.
Measured: Calculated from the eight sprint times recorded during the repeated sprint protocol on the test day.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Aug 2026
- Study start2 Jun 2026
- Primary completion28 Jun 2026
- Study completion28 Jun 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Exercise-Induced FatigueStudies of the same condition, open and under way.
- More trials run by Pamukkale UniversityThe 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
- Not applicable
- Intervention model
- Single group
- Model description
- All participants are assigned to a single study group and complete the same 8 × 30 m repeated sprint exercise protocol. Physiological, muscle oxygenation, cardiac autonomic, and neuromuscular responses are assessed before and at predefined time points after the exercise protocol. No control or comparator group is included.
- Masking
- None (open label)
- Enrolment
- 48 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pamukkale University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Engin Güneş Atabaş, Pamukkale University
- Investigators
- Engin Güneş Atabaş, PhD, Principal investigator, Pamukkale Üniversitesi
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07742163
- Sponsor's protocol ID
- PAU-NIRS-HRV-RSA-2026
- Status last verified
- Jul 2026
- First submitted
- 28 Jul 2026
- Last updated
- 3 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- 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 3 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Muscle Oxygenation and Autonomic Recovery After Repeated Sprint in Competitive Soccer Players: A NIRS-HRV-Based Field Study
- ClinicalTrials.gov ID
- NCT07742163
- Acronym / sponsor ID
- PAU-NIRS-HRV-RSA-2026
- Conditions
- Exercise-Induced Fatigue
- Keywords
- Repeated Sprint, Muscle Oxygenation, Near-Infrared Spectroscopy, Heart Rate Variability, Countermovement Jump, Exercise Recovery, Soccer, Blood Lactate
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 48 participants (actual)
- Lead sponsor
- Pamukkale UniversityUniversity, hospital or other
- Study start
- 2 Jun 2026 (actual)
- Primary completion
- 28 Jun 2026 (actual)
- Study completion
- 28 Jun 2026 (actual)
- First posted
- 3 Aug 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 evaluates the acute and short-term recovery responses to repeated sprint exercise in competitive male soccer players. Forty-eight licensed male soccer players complete an 8 × 30 m repeated sprint protocol under field conditions, with 25 seconds of active recovery between sprints.
The study examines several aspects of recovery. Muscle oxygenation is assessed using portable near-infrared spectroscopy sensors placed on the vastus lateralis and biceps femoris muscles. Cardiac autonomic recovery is evaluated using heart rate variability measurements obtained at baseline, 5 minutes, 30 minutes, and 24 hours after the repeated sprint protocol. Countermovement jump performance is measured before the protocol, 10 minutes after the protocol, and 24 hours later.
Sprint performance, blood lactate concentration, and perceived exertion are also recorded to characterize the physiological and performance demands of the repeated sprint protocol. The study aims to determine how muscle oxygenation, cardiac autonomic recovery, and neuromuscular performance change during the recovery period following repeated sprint exercise and whether these recovery indicators are associated with repeated sprint performance.
Detailed description
This study uses a single-group repeated-measures design to investigate muscle oxygenation, cardiac autonomic recovery, and neuromuscular performance responses following repeated sprint exercise in competitive male soccer players.
A total of 48 licensed male soccer players participate in the study. Participants regularly train and compete in soccer and have at least four years of soccer training experience.
During the measurement session, demographic and anthropometric characteristics are recorded first. Baseline measurements include heart rate variability, muscle oxygen saturation, blood lactate concentration, and countermovement jump performance. After a standardized 10-minute warm-up, participants complete an 8 × 30 m repeated sprint protocol. Each sprint is performed with maximal effort, and a 25-second active/light jogging recovery period is provided between sprints. Sprint times are recorded using an electronic timing gate system.
Muscle oxygenation is continuously assessed using portable near-infrared spectroscopy sensors placed on the vastus lateralis and biceps femoris muscles of the dominant leg. The evaluated muscle oxygenation variables include baseline muscle oxygen saturation, minimum muscle oxygen saturation, desaturation difference, 30-second reoxygenation muscle oxygen saturation, and reoxygenation rate.
Cardiac autonomic recovery is evaluated using heart rate variability derived from R-R interval recordings obtained with a Polar H10 chest strap. Five-minute HRV recordings are obtained at baseline, 5 minutes after the repeated sprint protocol, 30 minutes after the protocol, and 24 hours after the protocol. RMSSD and SDNN are used as the primary time-domain HRV parameters.
Neuromuscular performance is evaluated using countermovement jump height before the repeated sprint protocol, 10 minutes after the protocol, and 24 hours after the protocol. Blood lactate concentration is measured before the protocol and at 3 minutes after the protocol. Rating of perceived exertion is recorded after completion of the sprint protocol using the Borg CR10 scale.
The study is designed to characterize the time course of recovery following repeated sprint exercise and to examine relationships among sprint performance, muscle oxygenation, cardiac autonomic recovery, and neuromuscular performance. Because the study uses a single-group design without a control group, the findings are interpreted as recovery-related associations rather than evidence of causal effects.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- All participants are assigned to a single study group and complete the same 8 × 30 m repeated sprint exercise protocol. Physiological, muscle oxygenation, cardiac autonomic, and neuromuscular responses are assessed before and at predefined time points after the exercise protocol. No control or comparator group is included.
| Arm | Type | Receives |
|---|---|---|
| Repeated Sprint Exercise Group | Experimental | Other: 8 x 30 m Repeated Sprint ExerciseParticipants complete an 8 × 30 m repeated sprint exercise protocol with maximal effort and 25 seconds of active recovery between sprints. |
Who may qualify
- Ages
- 18 to 26 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Licensed male competitive soccer player
- Age between 18 and 26 years
- Regularly participating in soccer training within a club
- Actively participating in official competitions
- At least 4 years of soccer training experience
Key exclusion criteria (5 listed)
- Acute lower-extremity injury
- Acute illness on the measurement day
- Inability to complete the repeated sprint protocol
- Missing data at any required measurement time point
- Failure to complete the 24-hour follow-up measurements
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 |
|---|---|---|
| 8 x 30 m Repeated Sprint ExerciseParticipants perform eight 30-m maximal sprints under field conditions. A 25-second active recovery period consisting of light jogging is provided between consecutive sprints. Before the repeated sprint protocol, participants complete a standardized 10-minute warm-up consisting of low-intensity running, dynamic mobility exercises, and progressive acceleration runs. | Other | Repeated Sprint Exercise Group |
Primary outcome
Heart Rate Variability: RMSSD
Time frame: Baseline, 5 minutes, 30 minutes, and 24 hours after the repeated sprint protocol.
RMSSD was calculated from 5-minute R-R interval recordings obtained using a Polar H10 chest strap and analyzed with Kubios HRV Standard software. RMSSD was expressed in milliseconds and used as an indicator of parasympathetic cardiac autonomic recovery.
13 secondary outcomes
Baseline Muscle Oxygen Saturation
Time frame: Immediately before the repeated sprint protocol.
Minimum Muscle Oxygen Saturation
Time frame: During the 8 × 30 m repeated sprint protocol.
Muscle Oxygen Desaturation Difference
Time frame: Baseline and during the 8 × 30 m repeated sprint protocol on Study Day 1.
Thirty-Second Muscle Reoxygenation
Time frame: 30 seconds after completion of the repeated sprint protocol.
Muscle Reoxygenation Rate
Time frame: During the first 30 seconds after completion of the repeated sprint protocol.
Countermovement Jump Height
Time frame: Baseline, 10 minutes after the repeated sprint protocol, and 24 hours after the protocol.
Blood Lactate Concentration
Time frame: Immediately before and 3 minutes after the repeated sprint protocol.
Rating of Perceived Exertion
Time frame: Immediately after completion of the repeated sprint protocol.
Sprint Time Across Repetitions
Time frame: During each of the eight repetitions of the repeated sprint protocol on the test day.
Best Sprint Time
Time frame: During the 8 × 30 m repeated sprint protocol on the test day.
Mean Sprint Time
Time frame: During the 8 × 30 m repeated sprint protocol on the test day.
Total Sprint Time
Time frame: During the 8 × 30 m repeated sprint protocol on the test day.
Sprint Performance Decrement
Time frame: Calculated from the eight sprint times recorded during the repeated sprint protocol on the test day.
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 3 Aug 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Engin Güneş Atabaş, PhD principal investigator
Pamukkale Üniversitesi
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing 8 x 30 m Repeated Sprint Exercise in people with Exercise-Induced Fatigue, run by Pamukkale University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 5 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 3 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
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?
Heart Rate Variability: RMSSD (time frame: Baseline, 5 minutes, 30 minutes, and 24 hours after the repeated sprint protocol.). 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 3 Aug 2026.