Laser light before training left athletes stronger and less sore

Athletes need to hold their strength at a peak while recovering fast between sessions, which is why recovery gadgets attract so much attention and money. Low-level laser therapy, where light is applied to muscle tissue, had already been examined in a previous systematic review, but that work covered healthy participants in general rather than physically active athletes. Whether the technique helps the people most likely to pay for it was an open question. This review set out to answer it directly: does laser therapy improve muscular performance and soreness recovery specifically in athletes?

The reviewers swept PubMed, EMBASE and the Cochrane Library for trials published up to December 2020, including both trials where people were assigned at random and crossover designs. Study quality was judged using the Cochrane Handbook's risk of bias method for randomised trials. In total 24 studies made the cut and were pooled in a meta-analysis. The outcomes examined covered lower-limb muscle strength at several follow-up points, a soreness index, and blood markers including creatine kinase, interleukin-6 and thiobarbituric acid reactive substances.

Applying laser therapy before exercise significantly improved lower-limb muscle strength, and the benefit appeared at the 24-hour, 48-hour and 96-hour follow-ups as well as at 8 weeks. Soreness scores fell, as did blood concentrations of creatine kinase, interleukin-6 and thiobarbituric acid reactive substances, all of which are used as markers of muscle damage, inflammation and oxidative stress. There was also a trend towards more contraction repetitions and better oxygen uptake kinetics, though these were trends rather than clear effects. The reviewers conclude the evidence supports a performance benefit while stating a definite therapeutic effect is yet to be established.

This review extends earlier work that had only looked at healthy participants in general, showing the same direction of effect in physically active athletes, the group with the strongest interest in the answer. The consistency across strength, soreness and blood markers is what makes the signal interesting. But the reviewers' own conclusion is notably cautious: they call for additional trials with large sample sizes and robust designs before strong recommendations are made. How big the real-world benefit is, and which protocols deliver it, remain open questions.

If you have seen laser or light therapy devices marketed for recovery, this review is a reason to take the idea more seriously than the average gadget: the pooled evidence in athletes points towards better strength and less soreness when light is applied before exercise. It is equally a reason to hold off on strong conclusions, because the reviewers themselves say the effect is not yet definitively established. For now this sits in the promising category, worth knowing about and worth watching as bigger trials arrive.