Affiliations: [a] Federal University of Amapá, Campus Marco Zero, Macapá, AP, Brazil | [b] Biomedical Engineering Institute, Camilo Castelo Branco University, São Paulo, Brazil | [c] Human Movement Science Department, Federal University of São Paulo, Santos, SP, Brazil
Correspondence:
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Corresponding author: Antonio Balbin Villaverde, Biomedical Engineering Institute, Camilo Castelo Branco University (UNICASTELO), Estrada Dr. Altino Bondesan, 500, Distrito de Eugênio de Melo, 12247-004, São José dos Campos, São Paulo, Brazil. Tel.: +55 12 3905 4001; E-mail:[email protected]
Abstract: BACKGROUND: LED phototherapy can attenuate muscle fatigue and accelerate
muscle recovery in young persons, but little is known about
photobiomodulation effects on muscle strength in the elderly. OBJECTIVE: To assess the effects of LED phototherapy on the grip strength
and muscle fatigue of wrist flexors in elderly women. METHODS: Twenty-nine women were recruited and allocated to Placebo Group
(PG) (n= 14) and LED Group (LG) (n= 15). Grip strength, number of resisted
wrist flexion repetitions, and serum creatine kinase (CK) were measured. The
subjects were irradiated with one diode (638 nm, 150 mW, 11.7 J/cm2,
4.5 J/point) at four points on the wrist flexor muscles, and fatigue was
induced by exercise using 75% of one maximum repetition (1MR). When
muscle fatigue was reached, grip strength and CK were reassessed. RESULTS: In the LG, there was no intra-group difference for grip strength
(N), 217.7 ± 34.3 to 209.9 ± 35.3 (p = 0.063) whereas in the PG,
there was decrease in strength from 203.0 ± 22.5 to 181.4 ± 21.6
(p < 0.001). LED increased the number of repetitions by 22.0%. An
increase in CK (U/L) was observed in PG in all post-fatigue periods (p =
0.003) but no difference was found in the LG (p = 0.972). CONCLUSIONS: A single application of LED before muscle fatigue induction may
effectively maintain grip strength and reduce muscle fatigue and damage.
