Effects of Low-Level Laser Therapy (LLLT) in the Development of Exercise-Induced Skeletal Muscle Fatigue and Changes in Biochemical Markers Related to Postexercise Recovery

Abstract

investigating the effects of commonly used interventions, such as massage, lowintensity exercises, cryotherapy, hot-cold contrast baths, neuro-muscular electrical stimulation, and stretching, are few, and the results on effectiveness are mixed. 3 The rationale behind the use of these interventions is often related to mechanisms such as reducing postexercise inflammatory responses and the promotion of circulation and local metabolism t BacKgRound: Cell and animal studies have suggested that LLLT can reduce oxidative stress and inflammatory responses in muscle tissue. But it remains uncertain whether these findings can translate into humans in sport and exercise situations.t Methods: Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes; λ = 810 nm; 200 mW power output; 30 seconds of irradiation, applied in 2 locations over the biceps of the nondominant arm; 60 J of total energy) or placebo LLLT using an identical cluster probe. The intervention or placebo were applied 3 minutes before the performance of exercise. All subjects performed voluntary elbow flexion repetitions with a workload of 75% of their maximal voluntary contraction force until exhaustion.t Results: Active LLLT increased the number of repetitions by 14.5% (mean  SD, 39.6  4.3 versus 34.6  5.6; P = .037) and the elapsed time before exhaustion by 8.0% (P = .034), when compared to the placebo treatment. The biochemical markers also indicated that recovery may be positively affected by LLLT, as indicated by postexercise blood lactate levels (P.01), creatine kinase activity (P = .017), and C-reactive protein levels (P = .047), showing a faster recovery with LLLT application prior to the exercise. t conclusion: We conclude that pre-exercise irradiation of the biceps with an LLLT dose of 6 J per application location, applied in 2 locations, increased endurance for repeated elbow flexion against resistance and decreased postexercise levels of blood lactate, creatine kinase, and Creactive protein.t level oF evidence: Performance enhancement, level 1b.

Effects of Ultrasound versus Low Level Laser Therapy in Levofloxacin-Induced Rat Model of Knee Osteoarthritis

“…Up to our knowledge, no previous literature showed the effect of conventional US or LLLT on the serum level of CRP in OA of the knee joint. One study reported decrease in post-exercise elevation of blood CRP as well as lactate and creatine kinase due to pre-exercise irradiation by low-level laser [31].According to the results of the current study, continuous US therapy was more effective in reduction of the inflammatory markers; IL-6, INF-gamma as well as elevation of the antiinflammatory cytokine IL-10 in the serum of Lev-induced OA of knee joint in rats.…”

Effect of low-level laser therapy (GaAlAs - λ660 nm) on muscle function

“…Lopes-Martins et al (2006) also observed a decrease in fatigue after application of LLLT in rat electrically-stimulated muscle. Leal et al (2008;2010b;2010c) reported that LLLT increased the number and duration of contractions in high intensity, short duration exercises designed for volleyball players. Although LLLT apparently increased the muscle fiber diameter at 3 h, this enhancement probably reflected the lower fiber diameter in control muscles rather than an increase caused by LLLT; this conclusion is supported by the fact that the diameter of LLLT-treated muscles at 3 h was similar to the diameters of control and LLLT-treated muscles at 9 h. The reason for the lower fiber diameter in the 3 h control group is unclear.…”

Proprioceptive evaluation in healthy women undergoing Infrared Low Level Laser Therapy

“…Therefore, despite the LLLT is a widely used resource, it is in constant process of evaluating its various parameters and it needs more controlled studies to confirm their mechanisms of action in the various fields. The use of a single LLLT session has been used to assess their effects on endurance 16 , muscle performance, oxidative stress and fatigue 17 , however note that the use of only a therapeutic session is considered a limitation of this study, and that further studies could assess whether the sum therapies could significantly influence proprioception in healthy subjects.…”

“…When applied to stem cells it has been observed increased proliferation and cell differentiation 13 . In recent years, LLLT has been used aiming not only repair and analgesia, but to delay the levels of muscle fatigue 15 , reduce lactate levels, creatine kinase and C-reactive protein after exercise, and to increase muscle resistance 16 , increase muscle performance by delaying muscle fatigue 17 and increasing muscle torque 18 . Although biostimulants effects, there is a lack of research linking LLLT effects with proprioception, balance and movement control in healthy young women, since the research to date sticks in evaluating elderly 19 or with neurological disorders 20 and pain 21 ; so the aim of this study was to evaluate whether the application of infrared laser (830 nm) influence on proprioception in young women, given the potential both in sports and in athletes rehabilitation process.…”