Athletic Performance, Muscle Fatigue, Muscle Strength, Sports
Conditions
Keywords
Phototherapy, Laser therapy, Muscle fatigue, Muscle damage, Soccer
Brief summary
This study aims to investigate the effects of whole-body photobiomodulation on professional soccer players during a state championship. The primary question is whether photobiomodulation improves recovery, reduces muscle fatigue, and enhances performance compared to standard training without photobiomodulation.
Detailed description
Detailed Description: This randomized, controlled clinical trial aims to evaluate the effects of whole-body photobiomodulation (PBM) on recovery and performance in professional soccer players during a state championship. The intervention will be performed twice weekly on non-consecutive days for 8 weeks, in combination with each athlete's standard training routine. Participants will be allocated to either an active PBM group or a sham PBM group, both following identical procedures to maintain blinding. Throughout the study, participants will complete scheduled assessments at baseline, during, and after the 8-week period to monitor performance, muscle soreness, and hematological responses. Data will be analyzed using appropriate statistical tests, with a significance level of 5% (two-tailed).
Interventions
RADIATIONWhole-Body Photobiomodulation (PBM) (Active PBM)
This intervention consists of whole-body photobiomodulation delivered using a full-body PBM device. Sessions are performed twice weekly on non-consecutive days for 8 weeks, coinciding with the athletes' standard training. The device emits therapeutic light at specified wavelengths and power, targeting the entire body. The protocol is standardized according to prior research, ensuring consistent exposure for all participants in the active arm. The intervention aims to improve muscle performance and recovery while reducing delayed onset muscle soreness (DOMS).
RADIATIONSham PBM
Intervention Description (Sham PBM): Participants receive a sham photobiomodulation intervention using the same device and schedule, but without emission of therapeutic light. The procedure mimics the active intervention to maintain blinding while allowing comparison of outcomes, including muscle performance, DOMS, and blood markers.
Sponsors
Universidade Federal de Sao Carlos
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
Triple-masked trial. Participants wear protective eyewear; the sham device is physically identical and runs the same schedule, fan noise, and indicator covers, but emits no therapeutic light. Operators who run sessions are distinct from outcomes assessors; participants and assessors are unaware of group assignment. Scheduling and room procedures minimize cross-talk between teams. Randomization and assignment are concealed using sealed, opaque envelopes prepared by an independent researcher.
Intervention model description
Model Description: Participants are randomly assigned to two parallel groups: an Active Photobiomodulation (PBM) group and a Sham PBM group. Both groups undergo the same training schedule and assessment timeline, but only the active group receives therapeutic light exposure. There is no crossover between groups throughout the 8-week intervention period.
Eligibility
Sex/Gender
MALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Male professional soccer players currently competing in the championship * Age 18-35 years * Training frequency ≥5 times per week * Able to attend all PBM/sham sessions and all assessments during the 8-week intervention * Signed informed consent
Exclusion criteria
* Lower-limb musculoskeletal injury in the last 6 months or currently receiving treatment * Current use of phototherapy or any other recovery-enhancing modality * Chronic medical conditions that may affect performance or recovery * Known sensitivity or contraindication to light-based therapies * Inability to comply with the intervention or training schedule
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Delayed Onset Muscle Soreness (DOMS) | Baseline (T1), weekly (T2, weeks 1-8), and end of week 8 (T3). | Pain intensity measured using the Numeric Rating Scale (NRS; 0-10 points; higher scores = worse pain) during a maximal voluntary knee-extension contraction in sitting. Pain location/extent captured with a standardized pain drawing (exploratory). Primary analysis uses NRS. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Knee Extensor Strength (Hand-Held Dynamometry) | Baseline (T1), weekly (T2, weeks 1-8), end of week 8 (T3) | Peak force of dominant-leg knee extensors measured with a handheld dynamometer in standardized seated position; mean of two MVC attempts used for analysis. |
| Squat Jump (SJ) Height | Baseline (T1), weekly (T2, weeks 1-8), end of week 8 (T3) Unit: cm | Vertical jump height (cm) from Squat Jump (SJ) with hands on hips; mean of two trials; flight-time method on contact device. |
| Countermovement Jump (CMJ) Height | Baseline (T1), weekly (T2, weeks 1-8), end of week 8 (T3) | Vertical jump height (cm) from Countermovement Jump (CMJ) with hands on hips; mean of two trials; flight-time method on contact device. |
Countries
Brazil
Contacts
Primary ContactItalo A Oliveira, MSc
Outcome results
None listed