Journal des nouvelles physiothérapies

Abstrait

Phototherapy and Grip Muscle Performance

Peter C. Douris, Lev Borukhov, Jeffrey Espinoza, Joshua Klien, Katherine Levane, Tony Li, Ray Northern, Christina Rando and Michael Santo

Background: Grip strength and endurance has been shown to be an overall indicator of physical strength, function, and health. Previous research has provided evidence that phototherapy may increase muscle endurance. The purpose of this study was to investigate the effects of red/infrared light and blue/infrared light on grip endurance, lactic acid accumulation, and delayed onset muscle soreness (DOMS).

Materials and Methods: Fourteen subjects, seven men, and seven women (mean age 23.2 ± 1.7) took part in this randomized crossover double-blinded study. The subjects received either phototherapy (red/infrared probe with 4 red light emitting diodes (LEDs); λ= 670nm; 5 infrared laser diodes; λ= 850nm; 540mW power output; 65 seconds of irradiation, applied in 3 locations over the forearm and hand of the dominant arm; 35.1 J of total energy per site), phototherapy (blue/infrared probe with 28 blue LEDs emitting λ= 405nm; 8 infrared LEDs emitting λ= 880nm; 500mW of power output; 80 seconds, applied to the same points for a 40.0 J total energy per site) or placebo phototherapy using an identical cluster probe. The dosage in energy density units for the phototherapy treatments were 8 J/cm² per site. Each intervention was applied immediately before performance of the grip endurance exercise. All subjects performed voluntary grip strength repetitions until they reached 50% of their initial maximal voluntary contraction. The number of repetitions performed was utilized for data analysis. Lactic acid (La) accumulation was measured five minutes after the exercise has been completed. A visual pain analog scale measured DOMS at 24 and 48 hours post exercise.

Results: There were no significant differences between any of the three conditions on muscle endurance, La accumulation and pain scores as analyzed by Repeated Measures ANOVA.

Conclusion: The application of a standard therapeutic dosage of phototherapy did not improve grip endurance.