A Systematic Review and Meta-Analysis of the Acute Effects of Photobiomodulation Therapy on the Maximum Number of Repetitions in Resistance Exercise in Young Adults

Researchers investigated whether photobiomodulation therapy (PBMT) using red light, near-infrared light, lasers, or LEDs can improve muscular endurance during resistance training. The primary goal was to determine whether PBMT helps people perform more repetitions before fatigue and whether factors such as light source, sex, treatment dose, and muscle group influence the results.

Study Design

This was a systematic review and meta-analysis of randomized controlled trials.

Researchers analyzed:

  • 12 clinical studies
  • 346 healthy young adult participants
  • Resistance exercise performance outcomes
  • Laser and LED photobiomodulation treatments
  • Upper-body and lower-body exercise performance

What Researchers Measured

The primary outcome was:

  • Maximum number of repetitions completed during resistance exercise

Researchers also analyzed:

  • Muscle endurance
  • Exercise performance
  • Differences between LED and laser devices
  • Differences between upper- and lower-body muscles
  • Differences between men and women
  • Dose-response relationships

Key Findings

The meta-analysis found that photobiomodulation therapy significantly improved muscular endurance compared with placebo treatments.

Researchers reported:

  • Increased number of repetitions before fatigue
  • Improved resistance exercise performance
  • Benefits with both LED and laser devices
  • Positive effects for both upper- and lower-body muscles
  • Stronger improvements in upper-body exercise performance compared with lower-body performance

LED vs. Laser Results

One important finding was that:

  • LED-based photobiomodulation produced benefits similar to laser-based treatments.
  • No significant performance difference was found between LEDs and lasers for improving repetition performance.

This is especially relevant for red light therapy panel users because many consumer wellness devices utilize high-output LEDs rather than medical lasers.

Muscle Recovery & Performance Mechanisms

Researchers noted that previous studies suggest PBMT may:

  • Increase mitochondrial ATP production
  • Improve cellular energy availability
  • Reduce oxidative stress
  • Improve muscle metabolism
  • Delay fatigue development
  • Support exercise recovery processes

These mechanisms help explain why athletes and physically active individuals may experience improved endurance and training performance after photobiomodulation treatments.

Important Limitation

The authors noted that:

  • The number of available studies remains limited.
  • Evidence certainty was rated low to very low.
  • More large-scale trials are needed to determine ideal treatment parameters and confirm long-term benefits.

Conclusion

Researchers concluded that photobiomodulation therapy improves muscular endurance by increasing the number of repetitions healthy young adults can perform during resistance exercise. Benefits were observed with both LED and laser devices, supporting the growing use of red and near-infrared light therapy for exercise performance and recovery applications.

https://pubmed.ncbi.nlm.nih.gov/40205065/

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