Effect of Linear Polarized Near-infrared Light Irradiation and Light Exercise on Muscle Performance

Abstract

This study aimed to determine the effect of active warm-up by local muscle light exercise and passive warm-up by polarized light irradiation on skin and muscle temperatures and forearm muscle performance (muscle strength, power, endurance, and controlled force-exertion). Ten healthy males performed various grip tests before and after active (local muscle light exercise) and passive (linear polarized nearinfrared light irradiation) warm-ups. An active warm-up involved intermittent gripping exercise (contraction: 1 second and relaxation: 1 second) for 10 minutes using a sponge. A passive warm-up consisted of polarized light irradiation to the forearm (superficial digital flexor) for 10 minutes (irradiation: 5 seconds and rest: 1 second). Skin and muscle temperatures were measured during both warm-ups. Skin and muscle temperatures increased significantly after 5 minutes of local muscle light exercise and after 10 minutes of polarized light irradiation. Temperatures were significantly higher after 6 minutes of local muscle light exercise than after 6 minutes of polarized light irradiation. There were no significant differences of muscle strength, power, and controlled forceexertion before and after either warm-up. Average force outputs in all conditions significantly decreased with exertion time, and at 30, 60, 90, and 120 seconds they were higher in both warm-up conditions than in the non-warm-up condition. In conclusion, both warm-ups may contribute to improve muscle endurance performance in the decreasing force phase.

A systematic review of the effects of upper body warm-up on performance and injury

“…Level 1 evidence also supported the conclusion that passive heating or cooling warm-ups do not affect DOMS,12 13 41–43 or strength12 13 18 41–43 outcomes. Level 2 evidence shows that passive heating warm-ups do not have any impact on endurance outcomes,18 44 and level 3 evidence suggests that neither passive heating nor passive cooling warm-ups impact passive indicator,13 41–43 physiological13 18 42 or power18 outcomes. Thus, the only notable conclusion that can be presented regarding upper body passive heating and/or cooling warm-up is that passively heating muscles before a fatiguing eccentric exercise is likely to significantly minimise losses in flexibility in the days following the fatiguing exercise.…”

“…Owing to a wide range of investigated outcome categories, no evidence of the effects of low-load dynamic warm-up could be classified as level 1; however, level 2 evidence was found regarding the neutral effects of low-load dynamic warm-up on passive indicator outcomes 12 13 24. The neutral effects of low-load upper body dynamic warm-up on the following outcomes were classified as being level 3: power,10 18 22 24 strength,11–13 endurance,18 flexibility12 13 and physiological 11–13 18 21–24…”

Effect of high-intensity pulse irradiation with linear polarized near-infrared rays on muscle tone in patients with cerebrovascular disease: a randomized controlled trial

“…Phototherapy, such as laser therapy or linear polarized near-infrared ray (LPNR) irradiation, is one therapeutic approach that has been shown to be effective 1 , 2 ) . The equipment required for LPNR irradiation is a phototherapy device that emits infrared rays at deep penetrating wavelengths (600–1,600 nm) 3 , 4 , 5 , 6 , 7 ) . LPNR irradiation is commonly used in various therapeutic scenarios because of its noninvasiveness, safety, and simplicity 2 , 4 , 5 , 6 , 8 , 9 , 10 ) .…”