Photobiomodulation Therapy at 808 nm Does Not Improve Biceps Brachii Performance to Exhaustion and Delayed-Onset Muscle Soreness in Young Adult Women: A Randomized, Controlled, Crossover Trial
Bibliographic record
Abstract
Objective This study aims to investigate the effects of laser photobiomodulation (PBM) at 808 nm on biceps brachii performance to exhaustion, rating of perceived exertion (RPE), and delayed onset muscle soreness (DOMS) in untrained young women. Methods Thirteen young women (20.1 ± 2.9 years) participated in a crossover study in which they received, in a counterbalanced manner, active and placebo laser PBM on two occasions (T1 and T2), separated by a 7-day washout period. During T1 and T2, participants received active (100 mW output power, irradiance of 35.7 W cm–2, and total energy of 28 J/arm) or placebo laser irradiation on the biceps brachii muscle at 20 min before the repetitions-to-failure test [six sets at 60% of one-repetition maximum (1RM) until failure] for elbow flexion exercise. The number of repetitions performed and RPE over the six sets, as well as DOMS from basal up to 72 h after the repetitions-to-failure test, were recorded. Results There was a significant (time, p < 0.05) reduction in the number of repetitions performed and an increase in RPE over six sets, with no statistical differences between placebo and active laser conditions (treatment × time, p > 0.05). DOMS increased at 24 h postexercise and progressively returned to baseline after 72 h in both conditions (time, p < 0.05; treatment × time, p > 0.05). Conclusion Our results indicate that acute laser PBM at 808 nm does not improve biceps brachii performance to exhaustion, RPE, and DOMS in untrained women.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".