Photobiomodulation therapy increases functional capacity of patients with chronic kidney failure: randomized controlled trial.

Photobiomodulation (PBM) has been used in different populations as a strategy to attenuate muscle fatigue and improve exercise performance. Recent findings demonstrated that a single session with specific PBM doses during hemodialysis (HD) increased the upper limb muscle strength of chronic kidney failure (CKF) patients. Now, the primary objective of this study was to evaluate the chronic effect of PBM on the functional capacity of this population. Secondarily, we aimed at investigating the effects of PBM on the patients' strength, muscle thickness and echogenicity, perception of pain, fatigue, and quality of life. A randomized controlled trial was conducted in which the intervention group (IG, n = 14) received 24 sessions of PBM (810 nm, 5 diodes × 200 mW, 30 J/application site) on lower limb during HD. The control group (CG, n = 14) did not receive any physical therapy intervention, it only underwent HD sessions. As a result, there was an increase in the functional capacity (assessed through the six-minute walk test) for the IG compared with the CG [50.7 m (CI95% 15.63; 85.72), p = 0.01, large effect size, d = 1.12], as well as an improvement on lower limb muscle strength (assessed through the sit-and-stand test) [- 7.4 s (CI95% - 4.54; - 10.37), p = 0.00, large effect size, d = 1.99]. For other outcomes evaluated, no significant difference between-group was observed. Finally, PBM applied as monotherapy for 8 weeks in the lower limb improves functional capacity and muscle strength of CKF patients.

Effects of photobiomodulation on muscle strength in post-menopausal women submitted to a resistance training program.

The aim of this study was to compare the effects of resistance training of low volume and high intensity with or without photobiomodulation (PBM) on muscle strength and functional performance in post-menopausal women. Thirty-four post-menopausal women were randomized into resistance training (RTG, n = 17) or resistance training plus PBM (PBMG, n = 17). Individuals from both groups received the same RT protocol consisting of leg-press 45°, front lat pulldown, leg curl, chest press, and squat performed in two sets of 10 repetitions with a workload of 75% of one repetition maximum (1RM), twice per week, during 8 weeks. PBMG individuals also received, prior to the exercise session, PBM through a cluster containing 7 visible diodes (630 nm) and 7 infrared diodes (850 nm) with power of 100 mW each and energy of 4 J per diode, applied to the quadriceps femoris muscle; individuals from RTG received placebo PBM prior to the sessions, applied with the same device switched off. Muscle strength (1RM; isometric dynamometer), functional performance (Time Up and Go; Berg Balance Scale; 6-min walk test), and quality of life (World Health Organization Quality of Life-Bref) were performed before and after 8 weeks. Both groups increased muscle strength (p < 0.001) for all exercises, without group differences (p = 0.651). Quality of life (p = 0.015) and balance (p = 0.006) increased only in the RTG. The results suggest that PBM were not able for inducing additional benefits to RT to improve muscle strength in post-menopausal women.

Photobiomodulation therapy and NMES improve muscle strength and jumping performance in young volleyball athletes: a randomized controlled trial study in Brazil.

The purpose of this study was to investigate the effectiveness of adding photobiomodulation therapy and neuromuscular electrical stimulation (NMES) to volleyball athletes' training, focusing on muscle strength and jumping skills. Thirty-six athletes were randomly placed into three groups: control, photobiomodulation therapy, and NMES. The athletes trained to improve their muscle strength and jumping skills. The athletes in the photobiomodulation therapy group were submitted to photobiomodulation therapy (850 nm, continuous, energy density 0.8 J/cm2, radiant energy per point 6 J, total radiant energy 36 J) before undergoing strength and plyometric training. The NMES group additionally underwent NMES-based quadriceps femoris muscle strength training (base frequency 1 kHz, frequency modulation 70 Hz, intensity maximum tolerable). The variables analyzed were muscle strength, jumping ability, global impression, and jump frequency; they were measured at baseline and during follow-ups at 6 and 8 weeks. The statistical analysis was conducted on an intention-to-treat basis. The between-group differences and their respective 95% CIs were calculated using linear mixed models by using group, time, and group-versus-time interaction terms. Dominant lower limb strength improved the most in the NMES group compared to the control group (mean difference = 1.4, 95% CI = .5 to 2.4). Non-dominant lower limb strength increased in both the photobiomodulation therapy group (mean difference = 1.1, 95% CI = .3 to 2) and the NMES group (mean difference = 1.9, 95% CI = 1.1 to 2.8) compared to the control group, but the NMES group improved more than the photobiomodulation therapy group (mean difference = 0.8, 95% CI = 0.1 to 1.7). The NMES group had the greatest improvement in global perceived effect scale compared to the control group (mean difference = 1.1, 95% CI = 1 to 2.2). Dominant lower limb strength improved in the NMES group compared to the control group. Non-dominant lower limb strength increased in both the photobiomodulation therapy group and the NMES group compared to the control group, but the NMES group improved significantly more than the photobiomodulation therapy group; the NMES group also improved in the global perceived effect scale compared to the control group. This study found that, for volleyball athletes, photobiomodulation therapy and NMES both promoted benefits in terms of muscle-strength gain. In addition, these benefits were maintained for 2 weeks even after training was interrupted. Dominant lower limb strength improved in the NMES group compared to the control group. Non-dominant lower limb strength increased in both the photobiomodulation therapy group and the NMES group compared to the control group, but the NMES group improved significantly more than the photobiomodulation therapy group; the NMES group also improved in global impression of jumps compared to the control group.

Effects of Light-Emitting Diode Therapy on the Performance of Biceps Brachii Muscle of Young Healthy Males After 8 Weeks of Strength Training: A Randomized Controlled Clinical Trial.

Vieira, KVSG, Ciol, MA, Azevedo, PH, Pinfildi, CE, Renno, ACM, Colantonio, E, and Tucci, HT. Effects of light-emitting diode therapy on the performance of biceps brachii muscle of young healthy males after 8 weeks of strength training: a randomized controlled clinical trial. J Strength Cond Res 33(2): 433-442, 2019-We assessed the effect of adding light-emitting diode therapy (LEDT) to an 8-week strength training of biceps brachii in healthy young males. Forty-five participants were randomized into training plus LEDT, training plus sham LEDT, and control groups (n = 15 each). Individuals in the LEDT groups participated in strength training performed in a Scott machine at their maximum number of elbow flexion-extension repetitions. The LEDT was applied to biceps brachii of dominant limb at the end of training sessions (device "on" for LEDT and "off" for sham LEDT). Training loads were re-evaluated every 2 weeks. Controls did not receive training during 8 weeks. All groups were evaluated for 1 repetition maximum (1RM) and fatigue at baseline and 8 weeks. Additionally, the 2 LEDT groups were evaluated every 2 weeks for 1-RM and number of elbow flexion-extension repetitions. The groups were statistically different in mean difference and mean percent change of 1-RM from baseline to week 8 (p < 0.001). Analyzing the 2 LEDT groups, we found an interaction between group and time (p = 0.02), with a slightly faster increase in 1-RM for the LEDT than the sham LEDT. Over time, both groups decreased the number of repetitions of elbow flexion-extension (differences not statistically significant), possibly because of the increase of load over time. We found no difference in change of fatigue index among the 3 groups. Our study showed potential benefits to 1RM when LEDT is applied after a strength training session. Future studies might assess whether different doses of LEDT can reduce fatigue in strength training.

[Low level laser therapy : A narrative literature review on the efficacy in the treatment of rheumatic orthopaedic conditions]. / Low-Level-Lasertherapie : Eine narrative Literaturübersicht zur Wirksamkeit bei der Behandlung rheumatologisch-orthopädischer Krankheitsbilder.

BACKGROUND: In low level laser therapy (LLLT) low wattage lasers are used to irradiate the affected skin areas, joints, nerves, muscles and tendons without any sensation or thermal damage. Although the exact mechanism of its effect is still unknown, it seems beyond dispute that LLLT induces a variety of stimulating processes at the cellular level affecting cell repair mechanisms, the vascular system and lymphatic system. LLLT has been popular among orthopaedic practitioners for many years, whereas university medicine has remained rather sceptical about it. OBJECTIVES: Overview of studies on the efficacy of LLLT in the treatment of rheumatic orthopaedic conditions, i. e. muscle, tendon lesions and arthropathies. MATERIALS AND METHODS: Narrative literature review (PubMed, Web of Science). RESULTS: While earlier studies often failed to demonstrate the efficacy of LLLT, several recent studies of increasing quality proved the efficacy of LLLT in the treatment of multiple musculoskeletal pain syndromes like neck or lower back pain, tendinopathies (especially of the Achilles tendon) and epicondylolpathies, chronic inflammatory joint disorders like rheumatoid arthritis or chronic degenerative osteoarthritis of the large and small joints. In addition, there is recent evidence that LLLT can have a preventive capacity and can enhance muscle strength and accelerate muscle regeneration. CONCLUSION: LLLT shows potential as an effective, noninvasive, safe and cost-efficient means to treat and prevent a variety of acute and chronic musculoskeletal conditions. Further randomized controlled studies, however, are required to confirm this positive assessment.

What is the best moment to apply phototherapy when associated to a strength training program? A randomized, double-blinded, placebo-controlled trial : Phototherapy in association to strength training.

The effects of phototherapy (or photobiomodulation therapy) with low-level laser therapy (LLLT) and/or light-emitting diodes (LEDs) on human performance improvement have been widely studied. Few studies have examined its effect on muscular training and no studies have explored the necessary moment of phototherapy irradiations (i.e., before and/or after training sessions). The aim of this study was to determine the optimal moment to apply phototherapy irradiation when used in association with strength training. Forty-eight male volunteers (age between 18 to 35 years old) completed all procedures in this study. Volunteers performed the strength training protocol where either a phototherapy and/or placebo before and/or after each training session was performed using cluster probes with four laser diodes of 905 nm, four LEDs of 875 nm, and four LEDs of 640 nm-manufactured by Multi Radiance Medical™. The training protocol duration was 12 weeks with assessments of peak torque reached in maximum voluntary contraction test (MVC), load in 1-repetition maximum test (1-RM) and thigh circumference (perimetry) at larger cross-sectional area (CSA) at baseline, 4 weeks, 8 weeks, and 12 weeks. Volunteers from group treated with phototherapy before and placebo after training sessions showed significant (p < 0.05) changes in MVC and 1-RM tests for both exercises (leg extension and leg press) when compared to other groups. With an apparent lack of side effects and safety due to no thermal damage to the tissue, we conclude that the application of phototherapy yields enhanced strength gains when it is applied before exercise. The application may have additional beneficial value in post-injury rehabilitation where strength improvements are needed.

Influence of low-level laser therapy on vertical jump in sedentary individuals.

OBJECTIVE: To investigate the effects of low intensity laser (660nm), on the surae triceps muscle fatigue and power, during vertical jump in sedentary individuals, in addition to delayed onset muscle soreness. METHODS: We included 22 sedentary volunteers in the study, who were divided into three groups: G1 (n=8) without performing low intensity laser (control); G2 (n=7) subjected to 6 days of low intensity laser applications; and G3 (n=7) subjected to 10 days of low intensity laser applications. All subjects were evaluated by means of six evaluations of vertical jumps lasting 60 seconds each. In G2 and G3, laser applications in eight points, uniformly distributed directly to the skin in the region of the triceps surae were performed. Another variable analyzed was the delayed onset muscle soreness using the Visual Analog Scale of Pain. RESULTS: There was no significant difference in fatigue and mechanical power. In the evaluation of delayed onset muscle soreness, there was significant difference, being the first evaluation higher than the others. CONCLUSION: The low intensity laser on the triceps surae, in sedentary individuals, had no significant effects on the variables evaluated.

Influence of low-level laser therapy on vertical jump in sedentary individuals / Influência do laser de baixa potência no salto vertical em indivíduos sedentários / Influência do laser de baixa potência no salto vertical em indivíduos sedentários

Objective To investigate the effects of low intensity laser (660nm), on the surae triceps muscle fatigue and power, during vertical jump in sedentary individuals, in addition to delayed onset muscle soreness. Methods We included 22 sedentary volunteers in the study, who were divided into three groups: G1 (n=8) without performing low intensity laser (control); G2 (n=7) subjected to 6 days of low intensity laser applications; and G3 (n=7) subjected to 10 days of low intensity laser applications. All subjects were evaluated by means of six evaluations of vertical jumps lasting 60 seconds each. In G2 and G3, laser applications in eight points, uniformly distributed directly to the skin in the region of the triceps surae were performed. Another variable analyzed was the delayed onset muscle soreness using the Visual Analog Scale of Pain. Results There was no significant difference in fatigue and mechanical power. In the evaluation of delayed onset muscle soreness, there was significant difference, being the first evaluation higher than the others. Conclusion The low intensity laser on the triceps surae, in sedentary individuals, had no significant effects on the variables evaluated. .

Objetivo Verificar os efeitos do laser de baixa potência (660nm) sobre o tríceps sural na fadiga muscular e na potência, durante o salto vertical, em indivíduos sedentários, além da dor muscular de início tardio. Métodos Foram inclusos no estudo 22 voluntários sedentários, divididos em três grupos: G1 (n=8), sem realização de laser de baixa potência (controle); G2 (n=7), submetido a 6 dias de aplicações de laser de baixa potência; e G3 (n=7), submetido a 10 dias de aplicações de laser de baixa potência. Todos os indivíduos foram avaliados por meio de seis avaliações de saltos verticais, com duração de 60 segundos cada. No G2 e G3, foram realizadas aplicações de laser em oito pontos, distribuídos uniformemente e diretamente na pele, na região de do tríceps sural. Outra variável analisada foi a dor muscular de início tardia, utilizando a Escala Visual Analógica de Dor. Resultados Não houve diferença significativa na fadiga e na potência mecânica. Na avaliação da dor muscular tardia, houve diferença significativa, sendo a primeira avaliação maior do que as demais avaliações. Conclusão A aplicação do laser de baixa potência no tríceps sural, em indivíduos sedentários, não apresentou efeitos significativos nas variáveis avaliadas. .

Phototherapy with combination of super-pulsed laser and light-emitting diodes is beneficial in improvement of muscular performance (strength and muscular endurance), dyspnea, and fatigue sensation in patients with chronic obstructive pulmonary disease.

Phototherapy is an electrophysical intervention being considered for the retardation of peripheral muscular fatigue usually observed in chronic obstructive pulmonary disease (COPD). The objective of this study was to evaluate the acute effects of combination of super-pulsed laser and light-emitting diodes phototherapy on isokinetic performance in patients with COPD. Thirteen patients performed muscular endurance tests in an isokinetic dynamometer. The maximum voluntary isometric contraction (MVIC), peak torque (PT), and total work (TW) of the non-dominant lower limb were measured in two visits. The application of phototherapy or placebo (PL) was conducted randomly in six locations of femoral quadriceps muscle by using a cluster of 12 diodes (4 of 905 nm super-pulsed lasers, 0.3125 mW each; 4 of 875 nm LEDs, 17.5 mW each; and 4 of 640 nm LEDs, 15 mW each, manufactured by Multi Radiance Medical™). We found statistically significant increases for PT (174.7 ± 35.7 N · m vs. 155.8 ± 23.3 N · m, p = 0.003) and TW after application of phototherapy when compared to placebo (778.0 ± 221.1 J vs. 696.3 ± 146.8 J, p = 0.005). Significant differences were also found for MVIC (104.8 ± 26.0 N · m vs. 87.2 ± 24.0 N · m, p = 0.000), sensation of dyspnea (1 [0-4] vs. 3 [0-6], p = 0.003), and fatigue in the lower limbs (2 [0-5] vs. 5 [0.5-9], p = 0.002) in favor of phototherapy. We conclude that the combination of super-pulsed lasers and LEDs administered to the femoral quadriceps muscle of patients with COPD increased the PT by 20.2% and the TW by 12%. Phototherapy with a combination of super-pulsed lasers and LEDs prior to exercise also led to decreased sensation of dyspnea and fatigue in the lower limbs in patients with COPD.

Light-emitting diode therapy in exercise-trained mice increases muscle performance, cytochrome c oxidase activity, ATP and cell proliferation.

Light-emitting diode therapy (LEDT) applied over the leg, gluteus and lower-back muscles of mice using a LED cluster (630 nm and 850 nm, 80 mW/cm(2) , 7.2 J/cm(2) ) increased muscle performance (repetitive climbing of a ladder carrying a water-filled tube attached to the tail), ATP and mitochondrial metabolism; oxidative stress and proliferative myocyte markers in mice subjected to acute and progressive strength training. Six bi-daily training sessions LEDT-After and LEDT-Before-After regimens more than doubled muscle performance and increased ATP more than tenfold. The effectiveness of LEDT on improving muscle performance and recovery suggest applicability for high performance sports and in training programs. Positioning of the mice and light-emitting diode therapy (LEDT) applied on mouse legs, gluteus and lower-back muscles without contact.

Near-infrared light therapy to attenuate strength loss after strenuous resistance exercise.

CONTEXT: Near-infrared (NIR) light therapy is purported to act as an ergogenic aid by enhancing the contractile function of skeletal muscle. Improving muscle function is a new avenue for research in the area of laser therapy; however, very few researchers have examined the ergogenic effects of NIR light therapy and the influence it may have on the recovery process during rehabilitation. OBJECTIVE: To evaluate the ergogenic effect of NIR light therapy on skeletal muscle function. DESIGN: Crossover study. SETTING: Controlled laboratory. PATIENTS OR OTHER PARTICIPANTS: Thirty-nine healthy men (n = 21) and women (n = 18; age = 20.0 ± 0.2 years, height = 169 ± 2 cm, mass = 68.4 ± 1.8 kg, body mass index = 23.8 ± 0.4 kg/m(2)). INTERVENTION(S): Each participant received active and sham treatments on the biceps brachii muscle on 2 separate days. The order of treatment was randomized. A class 4 laser with a cumulative dose of 360 J was used for the active treatment. After receiving the treatment on each day, participants completed an elbow-flexion resistance-exercise protocol. MAIN OUTCOME MEASURE(S): The dependent variables were elbow range of motion, muscle point tenderness, and strength (peak torque). Analysis of variance with repeated measures was used to assess changes in these measures between treatments at baseline and at follow-up, 48 hours postexercise. Additionally, immediate strength loss postexercise was compared between treatments using a paired t test. RESULTS: Preexercise to postexercise strength loss for the active laser treatment, although small, was less than with the sham treatment (P = .05). CONCLUSIONS: Applied to skeletal muscle before resistance exercise, NIR light therapy effectively attenuated strength loss. Therefore, NIR light therapy may be a beneficial, noninvasive modality for improving muscle function during rehabilitation after musculoskeletal injury. However, future studies using higher treatment doses are warranted.

Low-level laser therapy associated with high intensity resistance training on cardiac autonomic control of heart rate and skeletal muscle remodeling in wistar rats.

BACKGROUND AND OBJECTIVE: Phototherapy plus dynamic exercise can enhance physical performance and improve health. The aim of our study was to evaluate the effect of low-level laser therapy (LLLT) associated with high intensity resistance training (HIT) on cardiac autonomic and muscle metabolic responses in rats. STUDY DESIGN/MATERIALS AND METHODS: Forty Wistar rats were randomized into 4 groups: sedentary control (CG), HIT, LLLT and HIT + LLLT. HIT was performed 3 times/week for 8 weeks with loads attached to the tail of the animal. The load was gradually increased by 10% of body mass until reaching a maximal overload. For LLLT, irradiation parameters applied to the tibialis anterior (TA) muscle were as follows: infrared laser (780 nm), power of 15 mW for 10 seconds, leading to an irradiance of 37.5 mW/cm(2), energy of 0.15 J per point and fluency of 3.8 J/cm(2). Blood lactate (BL), matrix metalloproteinase gelatinase A (MMP(-2)) gene expression and heart rate variability (HRV) indices were performed. RESULTS: BL significantly increased after 8-weeks for HIT, LLLT and HIT + LLLT groups. However, peak lactate when normalized by maximal load was significantly reduced for both HIT and HIT + LLLT groups (P<0.05). MMP-2 in the active form was significantly increased after HIT, LLLT and HIT + LLLT compared tom the CG (P<0.05). There was a significant reduction in low frequency [LF (ms(2))] and increase in high frequency [HF (un)] and HF (ms(2))] for the HIT, LLLT and HIT + LLLT groups compared with the CG (P < 0.05). However, the LF/HF ratio was further reduced in the LLLT and HIT + LLLT groups compared to the CG and HIT group (P < 0.05). CONCLUSION: These results provide evidence for the positive benefits of LLLT and HIT with respect to enhanced muscle metabolic and cardiac autonomic function in Wistar rats.

Pulsed electromagnetic fields on postmenopausal osteoporosis in Southwest China: a randomized, active-controlled clinical trial.

A randomized, active-controlled clinical trial was conducted to examine the effect of pulsed electromagnetic fields (PEMFs) on women with postmenopausal osteoporosis (PMO) in southwest China. Forty-four participants were randomly assigned to receive alendronate or one course of PEMFs treatment. The primary endpoint was the mean percentage change in bone mineral density of the lumbar spine (BMDL), and secondary endpoints were the mean percentage changes in left proximal femur bone mineral density (BMDF), serum 25OH vitamin D3 (25(OH)D) concentrations, total lower-extremity manual muscle test (LE MMT) score, and Berg Balance Scale (BBS) score. The BMDL, BMDF, total LE MMT score and BBS score were recorded at baseline, 5, 12, and 24 weeks. Serum concentrations of 25(OH)D were measured at baseline and 5 weeks. Using a mixed linear model, there was no significant treatment difference between the two groups in the BMDL, BMDF, total LE MMT score, and BBS score (P ≥ 0.05). For 25(OH)D concentrations, the effects were also comparable between the two groups (P ≥ 0.05) with the Mann-Whitney's U-test. These results suggested that a course of PEMFs treatment with specific parameters was as effective as alendronate in treating PMO within 24 weeks.

Effects of low level laser therapy (808 nm) on physical strength training in humans.

Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8±2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P = 0.033) and in the CG subjects (0.27%, P < 0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P = 0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.

Effect of cluster multi-diode light emitting diode therapy (LEDT) on exercise-induced skeletal muscle fatigue and skeletal muscle recovery in humans.

BACKGROUND AND OBJECTIVES: There are some indications that low-level laser therapy (LLLT) may delay the development of skeletal muscle fatigue during high-intensity exercise. There have also been claims that LED cluster probes may be effective for this application however there are differences between LED and laser sources like spot size, spectral width, power output, etc. In this study we wanted to test if light emitting diode therapy (LEDT) can alter muscle performance, fatigue development and biochemical markers for skeletal muscle recovery in an experimental model of biceps humeri muscle contractions. STUDY DESIGN/MATERIALS AND METHODS: Ten male professional volleyball players (23.6 [SD +/-5.6] years old) entered a randomized double-blinded placebo-controlled crossover trial. Active cluster LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW, 30 seconds total irradiation time, 41.7 J of total energy irradiated) or an identical placebo LEDT was delivered under double-blinded conditions to the middle of biceps humeri muscle immediately before exercise. All subjects performed voluntary biceps humeri contractions with a workload of 75% of their maximal voluntary contraction force (MVC) until exhaustion. RESULTS: Active LEDT increased the number of biceps humeri contractions by 12.9% (38.60 [SD +/-9.03] vs. 34.20 [SD +/-8.68], P = 0.021) and extended the elapsed time to perform contractions by 11.6% (P = 0.036) versus placebo. In addition, post-exercise levels of biochemical markers decreased significantly with active LEDT: Blood Lactate (P = 0.042), Creatine Kinase (P = 0.035), and C-Reative Protein levels (P = 0.030), when compared to placebo LEDT. CONCLUSION: We conclude that this particular procedure and dose of LEDT immediately before exhaustive biceps humeri contractions, causes a slight delay in the development of skeletal muscle fatigue, decreases post-exercise blood lactate levels and inhibits the release of Creatine Kinase and C-Reative Protein. Lasers Surg. Med. 41:572-577, 2009. (c) 2009 Wiley-Liss, Inc.