Exercise-Induced Fatigue
Conditions
Keywords
Repeated Sprint, Muscle Oxygenation, Near-Infrared Spectroscopy, Heart Rate Variability, Countermovement Jump, Exercise Recovery, Soccer, Blood Lactate, Neuromuscular Performance
Brief 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. 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.
Interventions
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.
Sponsors
Study design
Intervention 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.
Eligibility
Inclusion criteria
* 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
Exclusion criteria
* 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Heart Rate Variability: RMSSD | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Baseline Muscle Oxygen Saturation | Immediately before the repeated sprint protocol. | 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. |
| Minimum Muscle Oxygen Saturation | During the 8 × 30 m repeated sprint protocol. | 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. |
| Muscle Oxygen Desaturation Difference | Baseline and during the 8 × 30 m repeated sprint protocol on Study Day 1. | 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. |
| Thirty-Second Muscle Reoxygenation | 30 seconds after completion of the repeated sprint protocol. | 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. |
| Muscle Reoxygenation Rate | During the first 30 seconds after completion of the repeated sprint protocol. | 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. |
| Countermovement Jump Height | Baseline, 10 minutes after the repeated sprint protocol, and 24 hours after the protocol. | 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. |
| Blood Lactate Concentration | Immediately before and 3 minutes after the repeated sprint protocol. | Blood lactate concentration was measured in mmol/L using a Lactate Plus portable analyzer with capillary blood samples obtained from the fingertip. |
| Rating of Perceived Exertion | Immediately after completion of the repeated sprint protocol. | Perceived exertion was assessed using the Borg CR10 scale ranging from 0 to 10, where higher values indicate greater perceived exercise intensity. |
| Sprint Time Across Repetitions | During each of the eight repetitions of the repeated sprint protocol on the test day. | Completion time for each of the eight 30-m maximal sprints was recorded in seconds using a Witty wireless electronic timing gate system. |
| Best Sprint Time | During the 8 × 30 m repeated sprint protocol on the test day. | The fastest completion time among the eight 30-m maximal sprint repetitions was recorded in seconds. |
| Mean Sprint Time | During the 8 × 30 m repeated sprint protocol on the test day. | The arithmetic mean of the completion times recorded for the eight 30-m maximal sprint repetitions was calculated and expressed in seconds. |
| Total Sprint Time | During the 8 × 30 m repeated sprint protocol on the test day. | The sum of the completion times recorded for all eight 30-m maximal sprint repetitions was calculated and expressed in seconds. |
| Sprint Performance Decrement | Calculated from the eight sprint times recorded during the repeated sprint protocol on the test day. | 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. |
Countries
Turkey (Türkiye)
Contacts
Pamukkale Üniversitesi