Effect of 808 nm low-level laser therapy in exercise-induced skeletal muscle fatigue in elderly women

Abstract

Aging process involves several structural changes in muscle tissue which lead to decrease in musculoskeletal function. One of the most common physiological modifications is the increase in fatigability in elderly people, which leads to inability to maintain strength and motor control. In this context, low-level laser therapy (LLLT) has demonstrated positive results in reducing fatigue during physical exercise. Thus, this study aimed to investigate the effects of LLLT on skeletal muscle fatigue in elderly women. Twenty-four subjects divided in two groups entered a crossover randomized triple-blinded placebo-controlled trial. Active LLLT (808 nm wavelength, 100 mW, energy 7 J) or an identical placebo LLLT was delivered on the rectus femoris muscle immediately before a fatigue protocol. Subjects performed a fatigue protocol which consisted of voluntary isotonic contractions of knee flexion-extension performed with a load corresponding to 75 % of 1-MR (Maximum Repetition) during 60 s. Surface electromyography (SEMG) signals were recorded from rectus femoris muscle of dominant lower limb to evaluate peripheral fatigability using median frequency analysis of SEMG signal. The number of repetitions of flexion-extension during fatigue protocol was also compared between groups. The values of median frequency were used to calculate the slope coefficient. The results showed no difference in the slope comparing placebo LLLT and active LLLT groups (p = 0.293). However, a significant difference was observed in the number of repetitions between groups, after active LLLT, subjects demonstrated significantly higher number of repetitions (p = 0.047). In this study, LLLT was efficient in increasing the mean number of repetitions during knee flexion-extension exercise, although results have not shown delay electromyographic fatigue.

Photobiomodulation and physical exercise on strength, balance and functionality of elderly women

“…The PBM parameters used in this study were based on previous studies that demonstrated positive effects of irradiation in muscle performance in older women after a fatigue protocol [24,39]. In this study, the infrared wavelength was used based on its higher penetration power compared to red wavelengths [40].…”

“…Ferraresi et al [32] observed a significant increase in muscle strength in trained irradiated healthy men measured trough the leg-press evaluation. Moreover, Toma et al [24] observed that the mean number of repetitions performed during a fatigue protocol was higher when older volunteers received active PBM in comparison to the condition using placebo irradiation. In the study, the tendency of higher 1-MR values in the laser-trained irradiated women may be related to the stimulatory effect of PBM on cellular bioenergetics and ATP synthesis, which contribute to the increased of cellular energy [16,22,32].…”

“…This interaction could prevent muscle fatigue and enhance muscle strength as demonstrated in a previous study [24,25]. Moreover, it would provide benefits to improve the functional and balance capacity, within a population.…”

Effect of Low-Level Laser Therapy and Strength Training Protocol on Hand Grip by Dynamometry

“…9,10 Phototherapy has been widely used in research of different tissues, such as tendons, peripheral nerve, skin tissue, bones, and muscle. [11][12][13][14][15][16] In this context, low-level laser therapy (LLLT), and light emitting diode therapy (LEDT) are efficient on bioenergetics muscle activation, and these effects may influence performance during physical activities. Therefore, researchers started to investigate LLLT and LEDT as a way to improve muscle performance as LLLT and LEDT induce photochemical effects on cells by light absorption at photoreceptors;phenomenon described as photobiomodulation.…”

Sweep Frequency of Interferential Currents Therapy Attenuate Fatigue of Biceps Brachia Muscle in Normal Male Subjects: A Randomized Placebo Control Trial

“…These modalities include massage, low intensity exercise, cryotherapy, contrast bath , hyperbaric oxygen therapy , electromyostimulation and low level laser therapy. The results on their effectiveness have not been consistent [7][8][9][10][11][12][13]. Interferential currents therapy (IFC) is one of the most commonly used electrotherapeutic modalities within the clinical practice for the management of musculoskeletal pain [14].…”