Effects of Laser Photobiomodulation Therapy at 808 nm on Muscle Performance and Perceived Exertion in Elderly Women: A Randomized, Controlled, Crossover Trial.

Objective: This study aimed to investigate the acute effects of laser photobiomodulation (λ: 808 nm) therapy on muscle performance and perceived exertion in physically active elderly women. Methods: Seventeen physically active elderly women (72.6 ± 4.1 years) participated in a crossover study in which they received active or placebo laser therapy on the rectus femoris muscle on 2 occasions, separated by a 7-day washout period. On each occasion, the following performance outcomes were assessed: functional capacity by short physical performance battery, knee extensor strength by maximum voluntary isometric contraction, muscle endurance by repetitions-to-failure test and blood lactate levels, and perceived exertion. Results: No statistical (P > .05) differences were observed between active and placebo laser conditions for all muscle performance outcome (ie, short physical performance battery, maximum voluntary isometric contraction, repetitions-to-failure, and lactate) and perceived exertion. Conclusions: Acute laser photobiomodulation therapy at 808 nm does not improve muscle performance (functional capacity, strength, and endurance) and perceived exertion in physically active elderly women. Trial registration: NCT04241991. [ABSTRACT FROM AUTHOR]