Strength, Endurance and Recovery from Exercise

Lasers Med Sci. 2016 Jul 1. [Epub ahead of print]

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.

Vanin AA1,2, Miranda EF1,3, Machado CS1, de Paiva PR1,3, Albuquerque-Pontes GM1,3, Casalechi HL1, de Tarso Camillo de Carvalho P1,2,3, Leal-Junior EC4,5,6,7.

Author information

  • 1Laboratory of Phototherapy in Sports and Exercise, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil.
  • 2Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil.
  • 3Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil.
  • 4Laboratory of Phototherapy in Sports and Exercise, Universidade Nove de Julho (UNINOVE), São Paulo, SP, Brazil. ernesto.leal.junior@gmail.com.
  • 5Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil. ernesto.leal.junior@gmail.com.
  • 6Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho (UNINOVE), São Paulo, Brazil. ernesto.leal.junior@gmail.com.
  • 7Laboratory of Phototherapy in Sports and Exercise, Rua Vergueiro 235/249, CEP: 01504-001, São Paulo, SP, Brazil. ernesto.leal.junior@gmail.com.

Abstract

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.

 
 
Photomed Laser Surg. 2016 Apr 8. [Epub ahead of print]

Effects of Low-Level Laser Therapy Applied Before Treadmill Training on Recovery of Injured Skeletal Muscle in Wistar Rats.

Adabbo M1, Paolillo FR2, Bossini PS3, Rodrigues NC4, Bagnato VS2, Parizotto NA3.

Author information

  • 11 Biotechnology Program, Federal University of São Carlos (UFSCar) , São Carlos, SP, Brazil .
  • 22 Optics Group from São Carlos Institute of Physics (IFSC), University of São Paulo (USP) , São Carlos, SP, Brazil .
  • 33 Electrothermophototherapy Laboratory, Department of Physical Therapy, Federal University of São Carlos (UFSCar) , São Carlos, SP, Brazil .
  • 44 Department of Biomechanics, Medicine and Rehabilitation of Locomotor System, University of São Paulo (USP) , School of Medicine, Ribeirão Preto, SP, Brazil .

Abstract

OBJECTIVE:

The aim of this study was to analyze the effects of low-level laser therapy (LLLT) when associated with treadmill training on the recovery of skeletal muscle, during two periods of rest after muscle injury in rats.

BACKGROUND DATA:

Because of photostimulation, LLLT has been presented as an alternative for accelerating the tissue healing process.

MATERIALS AND METHODS:

Forty rats were divided into two groups (A and B) containing four subgroups each: GC (Control Group) – cryolesion untreated; EG (Exercise Group) – cryolesion treated with physical exercise; LG (Laser Group) – cryolesion treated with laser; ELG (Exercise and Laser Group) – cryolesion treated with laser and physical exercise. The right tibialis anterior (TA) of the middle belly was injured by a cooling iron bar (cryoinjury). Group A remained at rest for 3 days, whereas Group B remained at rest for 7 days. The laser parameters utilized were 780 nm with 15 mW average optical power and spot size of 0.04 cm2 applied during 10 sec, leading to 0.152 J and 3.8 J/cm2. Treadmill training with and without laser application was performed during 5 days, with each session lasting for 12 min at a velocity of 17 m/min. Subsequently, the TA muscle was removed for a histological and morphometric analysis.

RESULTS:

The damaged area was significantly smaller for the ELG at both periods of rest, 3 and 7 days, respectively (4.4 ± 0.42% and 3.5 ± 0.14%, p < 0.05), when compared with the LG (18.6 ± 0.64% and 7.5 ± 0.13%), the EG (21 ± 0.26% and 8.7 ± 0.32%), and the CG (23.9 ± 0.37% and 21.4 ± 0.38%). In addition, the number of blood vessels were significantly higher for the ELG at both periods of rest, 3 and 7 days, respectively (71.2 ± 13.51 and 104.5 ± 11.78, p < 0.05), when compared with the LG (60.6 ± 11.25 and 93.5 ± 16.87), the EG (51.6 ± 7.3 and 93.8 ± 15.1) and the CG (34.4 ± 2.54 and 65.7 ±14.1).

CONCLUSIONS:

The LLLT applied before the physical exercise on the treadmill stimulated the angiogenesis and accelerated the process of muscle recovery.

J Strength Cond Res. 2016 Apr 2. [Epub ahead of print]

Photobiomodulation therapy (PBMT) improves performance and accelerates recovery of high-level Rugby players in field test: A randomized, crossover, double-blind, placebo-controlled clinical study.

Pinto HD1, Vanin AA, Miranda EF, Tomazoni SS, Johnson DS, Albuquerque-Pontes GM, Aleixo Junior IO, Grandinetti VD, Casalechi HL, de Carvalho PT, Leal-Junior EC.

Author information

  • 11Laboratory of Phototherapy in Sports and Exercise, Universidade Nove de Julho (UNINOVE). São Paulo – SP, Brazil. 2Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE). São Paulo – SP, Brazil. 3Department of Pharmacology, University of São Paulo. São Paulo – SP, Brazil. 4Multi Radiance Medical. Solon – OH, USA. 5Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho (UNINOVE). São Paulo – SP, Brazil.

Abstract

While growing evidence supports the use of photobiomodulation therapy (PBMT) for performance and recovery enhancement, there have only been laboratory-controlled studies. Therefore, the aim of this study was to analyze the effects of PBMT in performance and recovery of high-level rugby players during an anaerobic field test. Twelve male high-level rugby athletes were recruited in this randomized, crossover, double-blinded, placebo-controlled trial. No interventions were performed before the Bangsbo Sprint Test (BST) at familiarization phase (week 1), at weeks 2 and 3 pre-exercise PBMT or placebo were randomly applied to each athlete. PBMT irradiation was performed at 17 sites of each lower limb, employing a cluster with 12 diodes (4 laser diodes of 905nm, 4 LED diodes of 875nm, and 4 LED diodes of 640nm, 30J per site – manufactured by Multi Radiance Medical™). Average time of sprints, best time of sprints, and fatigue index were obtained from BST. Blood lactate levels were assessed at baseline, and at 3, 10, 30 and 60 minutes after BST. Athletes’ perceived fatigue was also assessed through a questionnaire. PBMT significantly (p<0.05) improved average time of sprints and fatigue index in BST. PBMT significantly decreased percentage of change in blood lactate levels (p<0.05) and perceived fatigue (p<0.05). Pre-exercise PBMT with the combination of super-pulsed laser (low-level laser), red and infrared LEDs can enhance performance and accelerate recovery of high-level rugby players in field test. This opens a new avenue for wide use of PBMT in real clinical practice in sports settings.

J Athl Train. 2016 Mar 4. [Epub ahead of print]

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Using Pre-Exercise Photobiomodulation Therapy Combining Super-Pulsed Lasers and Light-Emitting Diodes to Improve Performance in Progressive Cardiopulmonary Exercise Tests.

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Miranda EF1,2, Vanin AA1,3, Tomazoni SS4, Grandinetti VD1,2, de Paiva PR1,2, Machado CD1, Monteiro KK1,3, Casalechi HL1,3, de Tarso P, de Carvalho C2,3, Leal-Junior EC1,2,3.
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Author information
1Laboratory of Phototherapy in Sports Exercise, Nove de Julho University, São Paulo, Brazil;
2Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University, São Paulo, Brazil;
3Postgraduate Program in Rehabilitation Sciences, Nove de Julho University, São Paulo, Brazil;
4Department of Pharmacology, University of São Paulo, Brazil.
.
Abstract
CONTEXT:
Skeletal muscle fatigue and exercise performance are novel areas of research and clinical application in the photobiomodulation field, and positive outcomes have been reported in several studies; however, the optimal measures have not been fully established.
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OBJECTIVE:
To assess the acute effect of photobiomodulation therapy (PBMT) combining superpulsed lasers (low-level laser therapy) and light-emitting diodes (LEDs) on muscle performance during a progressive cardiopulmonary treadmill exercise test.
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DESIGN:
Crossover study.
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SETTING:
Laboratory.
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PATIENTS OR OTHER PARTICIPANTS:
Twenty untrained male volunteers (age = 26.0 ± 6.0 years, height = 175.0 ± 10.0 cm, mass = 74.8 ± 10.9 kg).
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INTERVENTION(S):
Participants received PBMT with either combined superpulsed lasers and LED (active PBMT) or placebo at session 1 and the other treatment at session 2. All participants completed a cardiopulmonary test on a treadmill after each treatment. For active PBMT, we performed the irradiation at 17 sites on each lower limb (9 on the quadriceps, 6 on the hamstrings, and 2 on the gastrocnemius muscles), using a cluster with 12 diodes (four 905-nm superpulsed laser diodes with an average power of 0.3125 mW, peak power of 12.5 W for each diode, and frequency of 250 Hz; four 875-nm infrared LED diodes with an average power of 17.5 mW; and four 640-nm red LED diodes with an average power of 15 mW) and delivering a dose of 30 J per site.
.
MAIN OUTCOME MEASURE(S):
Distance covered, time until exhaustion, pulmonary ventilation, and dyspnea score.
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RESULTS:
The distance covered (1.96 ± 0.30 versus 1.84 ± 0.40 km, t19 = 2.119, P < .001) and time until exhaustion of the cardiopulmonary test (780.2 ± 91.0 versus 742.1 ± 94.0 seconds, t19 = 3.028, P < .001) was greater after active PBMT than after placebo. Pulmonary ventilation was greater (76.4 ± 21.9 versus 74.3 ± 19.8 L/min, t19 = 0.180, P = .004) and the score for dyspnea was lower (3.0 [0.5-9.0] versus 4.0 [0.0-9.0], U = 184.000, P < .001) after active PBMT than after placebo.
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CONCLUSIONS:
The combination of lasers and LEDs increased the time, distance, and pulmonary ventilation and decreased the score of dyspnea during a cardiopulmonary test.
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J Strength Cond Res. 2015 Mar 9. [Epub ahead of print]

Comparison Between Whole-body Vibration, LED, and Cycling Warm-up on High-intensity Physical Performance During Sprint Bicycle Exercise.

Teles MC1, Fonseca IA, Martins JB, de Carvalho MM, Xavier M, Costa SJ, de Avelar NC, Ribeiro VG, Salvador FS, Augusto L, Mendonça VA, Lacerda AC.

Author information

  • 11Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), School of Health and Biological Sciences, Exercise Physiology Laboratory, Diamantina, Brazil. 2Multicenter Post Graduation Program in Physiological Program, Brazilian Society of Physiology, Brazil. 3Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), School of Health and Biological Sciences, Inflammation and Metabolism Laboratory, Diamantina, Brazil. 4Federal University of Santa Catarina (UFSC), Araranguá, Brazil.

Abstract

The purpose of this study was to compare the effects of light emitting diode (LED) irradiation and whole-body vibration (WBV) delivered either in isolation or combination (LED + WBV), warm-up (WU) and a control (C) treatment on performance during a sprint bicycle exercise. Ten cyclists performed a 30-s sprint cycle test under these conditions. The LED light was applied at 4 points bilaterally. WBV consisted of 5 min of squats associated with WBV. LED + WBV consisted of WBV followed by LED therapy. WU consisted of 17 min of moderate intensity bicycle exercise. C consisted of 10 min at rest. Blood lactate (BL) and ammonia (BA) levels and skin temperature (ST) were determined. Peak power (842 ± 117 vs. 800 ± 106 vs. 809 ± 128 W [p = 0.02 and p = 0.01]), relative power (12.1 ± 1.0 vs. 11.5 ± 0.9 vs. 11.6 ± 1.0 W.kg [p = 0.02 and p = 0.02]), and relative work (277 ± 23 vs. 263 ± 24 vs. 260 ± 23 J.kg [p = 0.02 and p = 0.003]) were higher in the WU group compared with the control and LED groups. In the LED + WBV group, peak (833 ± 115 vs. 800 ± 106 W [p = 0.02]) and relative (11.9 ± 0.9 vs. 11.5 ± 0.9 W.kg [p = 0.02]) power were higher than those in the control group, and relative work (272 ± 22 vs. 260 ± 23 J.kg[p = 0.02]) were improved compared to the LED group. There were no differences for BL, BA and ST. The findings of this study confirmed the effectiveness of a warm-up as a preparatory activity and demonstrated that LED + WBV and WBV were as effective as WU in improving cyclist performance during a sprint bicycle exercise.

Lasers Med Sci. 2015 Jan 23. [Epub ahead of print]

Immediate effects of low-intensity laser (808 nm) on fatigue and strength of spastic muscle.

Dos Reis MC1, de Andrade EA, Borges AC, de Souza DQ, Lima FP, Nicolau RA, Andrade AO, Lima MO.

Author information

  • 1Laboratório de Engenharia de Reabilitação Sensório Motora, Universidade do Vale do Paraíba, Av. Shishima Hifumi, 2911, Urbanova, SP, 12244-000, Brazil, mah.crr@gmail.com.

Abstract

The cerebrovascular accident (CVA), high-impact disease II, affects the basic functions of the limbs, leading to changes of sensory, language, and motor functions. The search for resources that minimize the damage caused by this disease grows every day. The clinical use of low-intensity laser therapy (LILT) has provided major breakthroughs in the treatment of muscular disorders and prevention of muscle fatigue. Thus, the objective of the present study is to analyze the answers and immediate adaptations of the rectus femoris and vastus medialis of spastic hemiparetic patients, facing the increase in peak torque and triggering muscle fatigue, after application of LILT. Double-blind clinical trials were conducted with 15 volunteers post-CVA with spasticity, of both genders, between 40 and 80 years old. To this end, the volunteers went through three consecutive stages of rating (control, placebo, and laser). All performed tests of isometric contraction on the patient’s hemiparetic side. Significant differences were observed with regard to the increase in muscle performance (p?=?0.0043) and the reduction in blood lactate concentration (p?<?0.0001) of the post-LILT muscles. The LILT (diode laser, l100 mW 808 nm, 4.77 J/cm2/point, 40 s/AP) can be employed during and after spastic muscle-strengthening exercises, contributing to the improvement of motor function of the patient. After application of LILT, we found increased torque as well as decreased in lactate level in patients with spasticity.

Physiother Theory Pract. 2015 Jan 14:1-8. [Epub ahead of print]

Muscular pre-conditioning using light-emitting diode therapy (LEDT) for high-intensity exercise: a randomized double-blind placebo-controlled trial with a single elite runner.

Ferraresi C1, Beltrame T, Fabrizzi F, Nascimento ES, Karsten M, Francisco CO, Borghi-Silva A, Catai AM, Cardoso DR, Ferreira AG, Hamblin MR, Bagnato VS,Parizotto NA.

Author information

  • 1Department of Physical Therapy, Laboratory of Electrothermophototherapy, Federal University of São Carlos , São Paulo , Brazil .

Abstract

Abstract Recently, low-level laser (light) therapy (LLLT) has been used to improve muscle performance. This study aimed to evaluate the effectiveness of near-infrared light-emitting diode therapy (LEDT) and its mechanisms of action to improve muscle performance in an elite athlete. The kinetics of oxygen uptake (VO2), blood and urine markers of muscle damage (creatine kinase – CK and alanine) and fatigue (lactate) were analyzed. Additionally, some metabolic parameters were assessed in urine using proton nuclear magnetic resonance spectroscopy (1H NMR). A LED cluster with 50 LEDs (??=?850?nm; 50?mW 15?s; 37.5?J) was applied on legs, arms and trunk muscles of a single runner athlete 5?min before a high-intense constant workload running exercise on treadmill. The athlete received either Placebo-1-LEDT; Placebo-2-LEDT; or Effective-LEDT in a randomized double-blind placebo-controlled trial with washout period of 7?d between each test. LEDT improved the speed of the muscular VO2adaptation (?-9?s), decreased O2 deficit (?-10?L), increased the VO2 from the slow component phase (?+348?ml min-1) and increased the time limit of exercise (?+589?s). LEDT decreased blood and urine markers of muscle damage and fatigue (CK, alanine and lactate levels). The results suggest that a muscular pre-conditioning regimen using LEDT before intense exercises could modulate metabolic and renal function to achieve better performance.

Eur J Appl Physiol. 2014 Nov 23. [Epub ahead of print]

Effect of low-level laser therapy on muscle adaptation to knee extensor eccentric training.

Baroni BM1, Rodrigues R, Freire BB, Franke RD, Geremia JM, Vaz MA.

Author information

  • 1Universidade Federal de Ciências da Saúde de Porto Alegre, Sarmento Leite St., 245, Porto Alegre, RS, 90050-170, Brazil, bmbaroni@yahoo.com.br.

Abstract

PURPOSE:

Eccentric training has been popularized for physical conditioning and prevention/rehabilitation of musculoskeletal disorders, especially due to the expressive responses in terms of muscular strength gain. In view of evidence that low-level laser therapy (LLLT) is able to increase exercise performance and accelerate post-exercise recovery, the aim of this study was to verify the effect of LLLT on hypertrophy and strengthening of knee extensor muscles submitted to eccentric training.

METHOD:

Thirty healthy male subjects were randomized into three groups: Control Group (CG), Training Group (TG) and Training + LLLT Group (TLG). CG received no intervention, while TG and TLG were engaged on an 8-week knee extensor isokinetic eccentric training program. Only subjects from TLG were treated with LLLT (wavelength = 810 nm; power output = 200 mW; total dosage = 240 J) before each training session. Knee extensor muscle thickness and peak torque were assessed through ultrasonography and isokinetic dynamometry, respectively.

RESULTS:

CG presented no changes in any variable throughout the study, while eccentric training led to significant increases in muscle thickness and peak torque in TG and TLG. Subjects from TLG reached significantly higher percent changes compared to subjects from TG for sum of muscles’ thicknesses (15.4 vs. 9.4 %), isometric peak torque (20.5 vs. 13.7 %), and eccentric peak torque (32.2 vs. 20.0 %).

CONCLUSION:

LLLT applied before eccentric training sessions seems to improve the hypertrophic response and muscular strength gain in healthy subjects.

Lasers Med Sci. 2014 Nov;29(6):1839-47. doi: 10.1007/s10103-014-1592-6. Epub 2014 May 21.

Adjunctive use of combination of super-pulsed laser and light-emitting diodes phototherapy on nonspecific knee pain: double-blinded randomized placebo-controlled trial.

Leal-Junior EC1, Johnson DS, Saltmarche A, Demchak T.

Phototherapy with low-level laser therapy (LLLT) and light-emitting diode therapy (LEDT) has arisen as an interesting alternative to drugs in treatments of musculoskeletal disorders. However, there is a lack of studies investigating the effects of combined use of different wavelengths from different light sources like lasers and light-emitting diodes (LEDs) in skeletal muscle disorders. With this perspective in mind, this study aimed to investigate the effects of phototherapy with combination of different light sources on nonspecific knee pain. It was performed a randomized, placebo-controlled, double-blinded clinical trial. Eighty-six patients rated 30 or greater on the pain visual analogue scale (VAS) were recruited and included in study. Patients of LLLT group received 12 treatments with active phototherapy (with 905 nm super-pulsed laser and 875 and 640 nm LEDs, Manufactured by Multi Radiance Medical, Solon, OH, USA) and conventional treatment (physical therapy or chiropractic care), and patients of placebo group were treated at same way but with placebo phototherapy device. Pain assessments (VAS) were performed at baseline, 4th, 7th, and 10th treatments, after the completion of treatments and at 1-month follow-up visit. Quality of life assessments (SF-36®) were performed at baseline, after the completion of treatments and at 1-month follow-up visit. Our results demonstrate that phototherapy significantly decreased pain (p?<?0.05) from 10th treatment to follow-up assessments and significantly improved (p?<?0.05) SF-36® physical component summary at posttreatments and follow-up assessments compared to placebo. We conclude that combination of super-pulsed laser, red and infrared LEDs is effective to decrease pain and improve quality of life in patients with knee pain.

Lasers Med Sci. 2014 Nov;29(6):1967-76. doi: 10.1007/s10103-014-1611-7. Epub 2014 Jun 19.

Phototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes.

Antonialli FC1, De Marchi T, Tomazoni SS, Vanin AA, Dos Santos Grandinetti V, de Paiva PR, Pinto HD, Miranda EF, de Tarso Camillo de Carvalho P, Leal-Junior EC.

Abstract

Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905 nm lasers-0.3125 mW each, 4 of 875 nm LEDs-17.5 mW each, and 4 of 670 nm LEDs-15 mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50 J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1 min, 1, 24, 48, 72, and 96 h after eccentric exercise protocol employed to induce fatigue. Phototherapy increased (p?<?0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose). DOMS was significantly decreased compared to placebo (p?<?0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise. CK activity was significantly decreased (p?<?0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.

J Athl Train. 2014 Nov 14. [Epub ahead of print]

Near-Infrared Light Therapy to Attenuate Strength Loss After Strenuous Resistance Exercise.

Larkin-Kaiser KA1, Christou E, Tillman M, George S, Borsa PA.

Author information

  • 1Human Performance Laboratory, University of Calgary, Alberta, Canada;

Abstract

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/m2). 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.

Lasers Med Sci. 2013 Nov 19. [Epub ahead of print]

Effect of phototherapy (low-level laser therapy and light-emitting diode therapy) on exercise performance and markers of exercise recovery: a systematic review with meta-analysis.

Leal-Junior EC1, Vanin AA, Miranda EF, de Carvalho PD, Dal Corso S, Bjordal JM.

Author information

  • 1Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho, Rua Vergueiro, 235, 01504-001, São Paulo, SP, Brazil, ernesto.leal.junior@gmail.com.
  • Abstract

Recent studies have explored if phototherapy with low-level laser therapy (LLLT) or narrow-band light-emitting diode therapy (LEDT) can modulate activity-induced skeletal muscle fatigue or subsequently protect against muscle injury. We performed a systematic review with meta-analysis to investigate the effects of phototherapy applied before, during and after exercises. A literature search was performed in Pubmed/Medline database for randomized controlled trials (RCTs) published from 2000 through 2012. Trial quality was assessed with the ten-item PEDro scale. Main outcome measures were selected as: number of repetitions and time until exhaustion for muscle performance, and creatine kinase (CK) activity to evaluate risk for exercise-induced muscle damage. The literature search resulted in 16 RCTs, and three articles were excluded due to poor quality assessment scores. From 13 RCTs with acceptable methodological quality (?6 of 10 items), 12 RCTs irradiated phototherapy before exercise, and 10 RCTs reported significant improvement for the main outcome measures related to performance. The time until exhaustion increased significantly compared to placebo by 4.12 s (95 % CI 1.21-7.02, p?<?0.005) and the number of repetitions increased by 5.47 (95 % CI 2.35-8.59, p?<?0.0006) after phototherapy. Heterogeneity in trial design and results precluded meta-analyses for biochemical markers, but a quantitative analysis showed positive results in 13 out of 16 comparisons. The most significant and consistent results were found with red or infrared wavelengths and phototherapy application before exercises, power outputs between 50 and 200 mW and doses of 5 and 6 J per point (spot). We conclude that phototherapy (with lasers and LEDs) improves muscular performance and accelerate recovery mainly when applied before exercise.

Photomed Laser Surg. 2014 Feb;32(2):106-12. doi: 10.1089/pho.2013.3617. Epub 2014 Jan 23.

Effects of pre- or post-exercise low-level laser therapy (830 nm) on skeletal muscle fatigue and biochemical markers of recovery in humans: double-blind placebo-controlled trial.

Dos Reis FA1, da Silva BA, Laraia EM, de Melo RM, Silva PH, Leal-Junior EC, de Carvalho Pde T.

Author information

  • 11 Department of Physiotherapy, University Anhanguera-Uniderp , Campo Grande, MS, Brazil .

Abstract

OBJECTIVES:

The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before and after exercise on quadriceps muscle performance, and to evaluate the changes in serum lactate and creatine kinase (CK) levels.

METHODS:

The study was randomized, double blind, and placebo controlled.

PATIENTS:

A sample of 27 healthy volunteers (male soccer players) were divided into three groups: placebo, pre-fatigue laser, and post-fatigue laser. The experiment was performed in two sessions, with a 1 week interval between them. Subjects performed two sessions of stretching followed by blood collection (measurement of lactate and CK) at baseline and after fatigue of the quadriceps by leg extension. LLLT was applied to the femoral quadriceps muscle using an infrared laser device (830 nm), 0.0028 cm(2) beam area, six 60 mW diodes, energy of 0.6 J per diode (total energy to each limb 25.2 J (50.4 J total), energy density 214.28 J/cm(2), 21.42 W/cm(2) power density, 70 sec per leg. We measured the time to fatigue and number and maximum load (RM) of repetitions tolerated. Number of repetitions and time until fatigue were primary outcomes, secondary outcomes included serum lactate levels (measured before and 5, 10, and 15 min after exercise), and CK levels (measured before and 5 min after exercise).

RESULTS:

The number of repetitions (p=0.8965), RM (p=0.9915), and duration of fatigue (p=0.8424) were similar among the groups. Post-fatigue laser treatment significantly decreased the serum lactate concentration relative to placebo treatment (p<0.01) and also within the group over time (after 5 min vs. after 10 and 15 min, p<0.05 both). The CK level was lower in the post-fatigue laser group (p<0.01).

CONCLUSIONS:

Laser application either before or after fatigue reduced the post-fatigue concentrations of serum lactate and CK. The results were more pronounced in the post-fatigue laser group.

J Athl Train. 2013 Jan-Feb;48(1):57-67. doi: 10.4085/1062-6050-48.1.12.

Does phototherapy enhance skeletal muscle contractile function and postexercise recovery? A systematic review.

Borsa PA1, Larkin KA, True JM.

Author information

  • 1Department of Applied Physiology and Kinesiology, University of Florida, Gainesville 32611-8205, USA. pborsa@hhp.ufl.edu

Abstract

CONTEXT:

Recently, researchers have shown that phototherapy administered to skeletal muscle immediately before resistance exercise can enhance contractile function, prevent exercise-induced cell damage, and improve postexercise recovery of strength and function.

OBJECTIVE:

To critically evaluate original research addressing the ability of phototherapeutic devices, such as lasers and light-emitting diodes (LEDs), to enhance skeletal muscle contractile function, reduce exercise-induced muscle fatigue, and facilitate postexercise recovery.

DATA SOURCES:

We searched the electronic databases PubMed, SPORTDiscus, Web of Science, Scopus, and Rehabilitation & Physical Medicine without date limitations for the following key words: laser therapy, phototherapy, fatigue, exercise, circulation, microcirculation, and photobiomodulation.

STUDY SELECTION:

Eligible studies had to be original research published in English as full papers, involve human participants, and receive a minimum score of 7 out of 10 on the Physiotherapy Evidence Database (PEDro) scale.

DATA EXTRACTION:

Data of interest included elapsed time to fatigue, total number of repetitions to fatigue, total work performed, maximal voluntary isometric contraction (strength), electromyographic activity, and postexercise biomarker levels. We recorded the PEDro scores, beam characteristics, and treatment variables and calculated the therapeutic outcomes and effect sizes for the data sets.

DATA SYNTHESIS:

In total, 12 randomized controlled trials met the inclusion criteria. However, we excluded data from 2 studies, leaving 32 data sets from 10 studies. Twenty-four of the 32 data sets contained differences between active phototherapy and sham (placebo-control) treatment conditions for the various outcome measures. Exposing skeletal muscle to single-diode and multidiode laser or multidiode LED therapy was shown to positively affect physical performance by delaying the onset of fatigue, reducing the fatigue response, improving postexercise recovery, and protecting cells from exercise-induced damage.

CONCLUSIONS:

Phototherapy administered before resistance exercise consistently has been found to provide ergogenic and prophylactic benefits to skeletal muscle.

Photonics Lasers Med.  2012 Nov 1;1(4):267-286.

Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light.

Ferraresi C, Hamblin MR, Parizotto NA.

Source

Laboratory of Electro-thermo-phototherapy, Department of Physical Therapy, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil; and Department of Biotechnology, Federal University of São Carlos, São Carlos, São Paulo 13565-905, Brazil.

Abstract

The use of low level laser (light) therapy (LLLT) has recently expanded to cover areas of medicine that were not previously thought of as the usual applications such as wound healing and inflammatory orthopedic conditions. One of these novel application areas is LLLT for muscle fatigue and muscle injury. Since it is becoming agreed that mitochondria are the principal photoacceptors present inside cells, and it is known that muscle cells are exceptionally rich in mitochondria, this suggests that LLLT should be highly beneficial in muscle injuries. The ability of LLLT to stimulate stem cells and progenitor cells means that muscle satellite cells may respond well to LLLT and help muscle repair. Furthermore the ability of LLLT to reduce inflammation and lessen oxidative stress is also beneficial in cases of muscle fatigue and injury. This review covers the literature relating to LLLT and muscles in both preclinical animal experiments and human clinical studies. Athletes, people with injured muscles, and patients with Duchenne muscular dystrophy may all benefit.

Photomed Laser Surg.  2011 Sep;29(9):639-45. Epub 2011 Jul 12.

Effects of infrared-LED illumination applied during high-intensity treadmill training in postmenopausal women.

Paolillo FR, Milan JC, Aniceto IV, Barreto SG, Rebelatto JR, Borghi-Silva A, Parizotto NA, Kurachi C, Bagnato VS.

Source

Optics Group from Instituto de Física de São Carlos, University of São Paulo, São Paulo, Brazil. fer.nanda.rp@hotmail.com

Abstract

BACKGROUND DATA:

Technology and physical exercise can enhance physical performance during aging.

OBJECTIVE:

The purpose of this study was to investigate the effects of infrared-light-emitting diode (LED) illumination (850nm) applied during treadmill training.

MATERIALS AND METHODS:

Twenty postmenopausal women participated in this study. They were randomly divided into two groups. The LED group performed treadmill training associated with infrared-LED illumination (n=10) and the control group performed only treadmill training (n=10). The training was performed during 3 months, twice a week during 30 min at intensities between 85 and 90% of maximal heart rate. The irradiation parameters were 31mW/cm(2), treatment time 30min, 14,400 J of total energy and 55.8 J/cm(2) of fluence. Physiological, biomechanical, and body composition parameters were measured at the baseline and after 3 months.

RESULTS:

Both groups improved the time of tolerance limit (Tlim) (p<0.05) during submaximal constant-speed testing. The peak torque did not differ between groups. However, the results showed significantly higher values of power [from 56±10 to 73±8 W (p=0.002)] and total work [from 1,537±295 to 1,760±262 J (p=0.006)] for the LED group when compared to the control group [power: from 58±14 to 60±15?W (p 0.05) and total work: from 1,504±404 to 1,622±418 J ( ?0.05)]. The fatigue significantly increased for the control group [from 51±6 to 58±5 % (p=0.04)], but not for the LED group [from 60±10 to 60±4 % (p 0.05)]. No significant differences in body composition were observed for either group.

CONCLUSIONS:

Infrared-LED illumination associated with treadmill training can improve muscle power and delay leg fatigue in postmenopausal women.

Lasers Med Sci.  2011 Aug 26. [Epub ahead of print]

Effects of low-level laser therapy (808 nm) on isokinetic muscle performance of young women submitted to endurance training: a randomized controlled clinical trial.

de Brito Vieira WH, Ferraresi C, de Andrade Perez SE, Baldissera V, Parizotto NA.

Source

Department of Physical Therapy, Federal University of Rio Grande do Norte (Campus Universitário Lagoa Nova), Av. Senador Salgado Filho, 3000, 59072-970, Natal, RN, Brazil, mailto:hericsonfisio@yahoo.com.br.

Abstract

Low-level laser therapy (LLLT) has shown efficacy in muscle bioenergetic activation and its effects could influence the mechanical performance of this tissue during physical exercise. This study tested whether endurance training associated with LLLT could increase human muscle performance in isokinetic dynamometry when compared to the same training without LLLT. The primary objective was to determine the fatigue index of the knee extensor muscles (FIext) and the secondary objective was to determine the total work of the knee extensor muscles (TWext). Included in the study were 45 clinically healthy women (21?±?1.78 years old) who were randomly distributed into three groups: CG (control group), TG (training group) and TLG (training with LLLT group). The training for the TG and TLG groups involved cycle ergometer exercise with load applied to the ventilatory threshold (VT) for 9 consecutive weeks. Immediately after each training session, LLLT was applied to the femoral quadriceps muscle of both lower limbs of the TLG subjects using an infrared laser device (808 nm) with six 60-mW diodes with an energy of 0.6 J per diode and a total energy applied to each limb of 18 J. VT was determined by ergospirometry during an incremental exercise test and muscle performance was evaluated using an isokinetic dynamometer at 240°/s. Only the TLG showed a decrease in FIext in the nondominant lower limb (P?=?0.016) and the dominant lower limb (P?=?0.006). Both the TLG and the TG showed an increase in TWext in the nondominant lower limb (P?<?0.001 and P?=?0.011, respectively) and in the dominant lower limb (P?<?0.000 and P?<?0.000, respectively). The CG showed no reduction in FIext or TWext in either lower limb. The results suggest that an endurance training program combined with LLLT leads to a greater reduction in fatigue than an endurance training program without LLLT. This is relevant to everyone involved in sport and rehabilitation.

Lasers Med Sci.  2011 May;26(3):349-58. Epub 2010 Nov 18.

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

Ferraresi C, de Brito Oliveira T, de Oliveira Zafalon L, de Menezes Reiff RB, Baldissera V, de Andrade Perez SE, Matheucci Júnior E, Parizotto NA.

Source

Laboratory of Electrothermophototherapy, Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235, 13565-905, São Carlos, SP, Brazil. cleber.ferraresi@gmail.com

Abstract

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.

Lasers Med Sci. 2012 Jan;27(1):231-6. doi: 10.1007/s10103-011-0955-5. Epub 2011 Jul 8.

Low-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress.

De Marchi T1, Leal Junior EC, Bortoli C, Tomazoni SS, Lopes-Martins RA, Salvador M.

Author information

  • 1Institute of Biotechnology, University of Caxias do Sul, Caxias do Sul, RS, Brazil.

Abstract

The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots – 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.

Lasers Med Sci.  2011 Jul 22. [Epub ahead of print]

Red (660 nm) and infrared (830 nm) low-level laser therapy in skeletal muscle fatigue in humans: what is better?

de Almeida P, Lopes-Martins RA, De Marchi T, Tomazoni SS, Albertini R, Corrêa JC, Rossi RP, Machado GP, da Silva DP, Bjordal JM, Leal Junior EC.

Source

Post Graduate Program in Rehabilitation Sciences, Nove de Julho University (UNINOVE), Rua Vergueiro, 235, 01504-001, São Paulo, SP, Brazil.

Abstract

In animal and clinical trials low-level laser therapy (LLLT) using red, infrared and mixed wavelengths has been shown to delay the development of skeletal muscle fatigue. However, the parameters employed in these studies do not allow a conclusion as to which wavelength range is better in delaying the development of skeletal muscle fatigue. With this perspective in mind, we compared the effects of red and infrared LLLT on skeletal muscle fatigue. A randomized double-blind placebo-controlled crossover trial was performed in ten healthy male volunteers. They were treated with active red LLLT, active infrared LLLT (660 or 830 nm, 50 mW, 17.85 W/cm(2), 100 s irradiation per point, 5 J, 1,785 J/cm(2) at each point irradiated, total 20 J irradiated per muscle) or an identical placebo LLLT at four points of the biceps brachii muscle for 3 min before exercise (voluntary isometric elbow flexion for 60 s). The mean peak force was significantly greater (p?<?0.05) following red (12.14%) and infrared LLLT (14.49%) than following placebo LLLT, and the mean average force was also significantly greater (p?<?0.05) following red (13.09%) and infrared LLLT (13.24%) than following placebo LLLT. There were no significant differences in mean average force or mean peak force between red and infrared LLLT. We conclude that both red than infrared LLLT are effective in delaying the development skeletal muscle fatigue and in enhancement of skeletal muscle performance. Further studies are needed to identify the specific mechanisms through which each wavelength acts.

Photochem Photbiol.  2011 Jul 12. doi: 10.1111/j.1751-1097.2011.00968.x. [Epub ahead of print]

Low-level laser therapy improves skeletal muscle performance, decreases skeletal muscle damage and modulates mRNA expression of COX-1 and COX-2 in a dose-dependent manner.

de Almeida P, Lopes-Martins RA, Tomazoni SS, Junior JA, de Tarso Camillo de Carvalho P, Bjordal JM, Leal EC Junior.

Source

Post Graduate Program in Rehabilitation Sciences, Nove de Julho University (UNINOVE), São Paulo, SP – Brazil. Laboratory of Pharmacology and Experimental Therapeutics, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, SP – Brazil. Centre for Evidence-Based Practice, Bergen University College, Bergen – Norway.

Abstract

We tested if modulation in mRNA expression of COX-1 and COX-2 can be related to protective effects of phototherapy in skeletal muscle. Thirty male Wistar rats were divided into five groups receiving either one of four laser doses (0.1, 0.3, 1.0 and 3.0 J) or a no-treatment control group. Laser irradiation (904 nm, 15 mW average power) was performed immediately before the first contraction for treated groups. Electrical stimulation was used to induce six tetanic tibial anterior muscle contractions. Immediately after sixth contraction, blood samples were collected in order to evaluate CK activity and muscles were dissected and frozen in liquid nitrogen in order to evaluate mRNA expression of COX-1 and COX-2. The 1.0 J and 3.0 J groups showed significant enhancement (p<0.01) in total work performed in 6 tetanic contractions compared to control group. All laser groups, except the 3.0 J group, presented significantly lower post-exercise CK activity than control group. Additionally, 1.0 J group showed increased COX-1 and decreased COX-2 mRNA expression compared to control group and 0.1, 0.3 and 3.0 J laser groups (p<0.01). We conclude that pre-exercise infrared laser irradiation with dose of 1.0 J enhances skeletal muscle performance and decreases post-exercise skeletal muscle damage and inflammation.

Lasers Med Sci.  2011 Jul 8. [Epub ahead of print]

Low-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress.

De Marchi T, Leal Junior EC, Bortoli C, Tomazoni SS, Lopes-Martins RA, Salvador M.

Source

Laboratory of Oxidative Stress and Antioxidants, Institute of Biotechnology, University of Caxias do Sul, Rua Francisco Getúlio Vargas, 1130, 950070-560, Caxias do Sul, RS, Brazil.

Abstract

The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots – 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p?=?0.01; time to exhaustion, p?=?0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p?=?0.0001) and protein (p?=?0.0230) damages, as well as the activities of SOD (p?=?0.0034), CK (p?=?0.0001) and LDH (p?=?0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.

Lasers Med Sci. 2010 Nov 18. [Epub ahead of print]

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

Valdissera V, de Andrade Perez SE, Júnior EM, Parizotto NA.

Laboratory of Electrothermophototherapy, Department of Physical Therapy, Federal University of São Carlos, Rodovia Washington Luís, km 235, 13565-905, São Carlos, SP, Brazil, cleber.ferraresi@gmail.com.

Abstract

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.

Lasers Surg Med. 2010 Aug;42(6):577-83.

 Evaluation of inflammatory biomarkers associated with oxidative stress and histological assessment of low-level laser therapy in experimental myopathy.

 Servetto N, Cremonezzi D, Simes JC, Moya M, Soriano F, Palma JA, Campana VR. Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Santa Rosa 1085, (5000) Córdoba, Argentina.

Abstract

The objective of the present work was to study the effect of helium-neon (He-Ne) and gallium-arsenide (Ga-As) laser upon inflammatory biomarkers associated with oxidative stress: fibrinogen, nitric oxide (NO), L-citrulline, and superoxide dismutase (SOD). These were evaluated through histological assessment, in rats with experimental myopathy.

MATERIALS AND METHODS: The groups studied were: (A) control, (B) injured, (C) injured and treated with He-Ne laser, (D) injured and treated with Ga-As laser, (E) irradiated with He-Ne; and (F) irradiated with Ga-As laser. Myopathy was induced by injecting 0.05 mg/rat/day of adrenaline in the left posterior limb muscle at the same point on 5 consecutive days, in groups B, C, and D. Low-level laser therapy (LLLT) was applied with 9.5 J/cm(2) daily for 7 consecutive days with each laser. The determination of the biomarkers was made by spectrophotometry. The muscles (5/8, single blinded) were stained with Gomori Trichrome and examined by optic microscopy. The quantitative variables were statistically analyzed by the Fisher’s test and categorical data by the Axionvision 4.8 program. Pearson’s chi-squared test was applied, setting significant difference at P < 0.05 for all cases.

RESULTS: In group B, the biomarkers were significantly increased compared to the other groups (P < 0.001), except for NO which in group B decreased significantly (P < 0.001). In group B, there was a higher inflammatory infiltration level (80.67%) in relation to destroyed fibers.

CONCLUSIONS: LLLT caused significant changes in inflammatory biomarkers and oxidative stress: decreased levels of fibrinogen, L-citrulline and SOD as opposed to the increase of NO in rats with experimental myopathies and significant muscle recovery.

Photodermatol Photoimmunol Photomed. 2010 Aug;26(4):192-7.

Phenotype characterization of pericytes during tissue repair following low-level laser therapy.

 

Medrado A, Costa T, Prado T, Reis S, Andrade Z.

Laboratory of Experimental Pathology, Oswaldo Cruz Foundation, Salvador, Brazil.

Abstract

Background/purpose: The action of low-level laser therapy (LLLT) on pericytes during wound healing is not well established. The objective of this study was to identify the effect of laser treatment on pericytes during tissue repair.

Methods: Punch biopsies were performed on 40 Wistar rats. Twenty animals had their wounds treated with a dose of 4 J/cm(2) using a 670 nm diode laser (9 mW output, 0.031 W/cm(2)) every other day, while the controls received sham irradiation. Animals were sacrificed 3, 7, 10 and 14 days after punch biopsy. Immunohistochemistry staining with anti-desmin, anti-smooth muscle alpha-actin and anti-NG2 antibodies was used to characterize and count pericytes around blood vessels and myofibroblasts dispersed in the extracellular matrix (ECM). The morphology of pericytes was confirmed by transmission electronic microscopy.

Results: The laser group exhibited significantly more smooth muscle alpha-actin-positive staining cells at day 7 and more desmin-positive staining cells at day 10 around blood vessels. Laser treatment was also associated with higher numbers of NG2-positive staining cells, especially on days 3 and 7 post-biopsy (P<0.05). Ultrastructural findings confirmed the presence of pericytes sharing the basal membrane with endothelial cells. Conclusion: LLLT stimulated the proliferation and migration of pericytes to the ECM and their phenotypic modulation to myofibroblasts.

Eur J Appl Physiol. 2010 Jul 3. [Epub ahead of print]

 Low level laser therapy before eccentric exercise reduces muscle damage markers in humans.

 Baroni BM, Leal Junior EC, De Marchi T, Lopes AL, Salvador M, Vaz MA.

Exercise Research Laboratory (LAPEX), Federal University of Rio Grande do Sul (UFRGS), Rua Felizardo, 750-Bairro Jardim Botânico, Porto Alegre, RS, 90690-200, Brazil, bmbaroni@yahoo.com.br.

Abstract

The purpose of the present study was to determine the effect of low level laser therapy (LLLT) treatment before knee extensor eccentric exercise on indirect markers of muscle damage. Thirty-six healthy men were randomized in LLLT group (n = 18) and placebo group (n = 18). After LLLT or placebo treatment, subjects performed 75 maximal knee extensors eccentric contractions (five sets of 15 repetitions; velocity = 60 degrees seg(-1); range of motion = 60 degrees ). Muscle soreness (visual analogue scale-VAS), lactate dehydrogenase (LDH) and creatine kinase (CK) levels were measured prior to exercise, and 24 and 48 h after exercise. Muscle function (maximal voluntary contraction-MVC) was measured before exercise, immediately after, and 24 and 48 h post-exercise. Groups had no difference on kineanthropometric characteristics and on eccentric exercise performance. They also presented similar baseline values of VAS (0.00 mm for LLLT and placebo groups), LDH (LLLT = 186 IU/l; placebo = 183 IU/l), CK (LLLT = 145 IU/l; placebo = 155 IU/l) and MVC (LLLT = 293 Nm; placebo = 284 Nm). VAS data did not show group by time interaction (P = 0.066). In the other outcomes, LLLT group presented (1) smaller increase on LDH values 48 h post-exercise (LLLT = 366 IU/l; placebo = 484 IU/l; P = 0.017); (2) smaller increase on CK values 24 h (LLLT = 272 IU/l; placebo = 498 IU/l; P = 0.020) and 48 h (LLLT = 436 IU/l; placebo = 1328 IU/l; P < 0.001) post-exercise; (3) smaller decrease on MVC immediately after exercise (LLLT = 189 Nm; placebo = 154 Nm; P = 0.011), and 24 h (LLLT = 249 Nm; placebo = 205 Nm; P = 0.004) and 48 h (LLLT = 267 Nm; placebo = 216 Nm; P = 0.001) post-exercise compared with the placebo group. In conclusion, LLLT treatment before eccentric exercise was effective in terms of attenuating the increase of muscle proteins in the blood serum and the decrease in muscle force.

J Orthop Sports Phys Ther. 2010 Apr 12. [Epub ahead of print]

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

Leal Junior EC, Lopes-Martins RA, Frigo L, De Marchi T, Rossi RP, de Godoi V, Tomazoni SS, da Silva DP, Basso M, Filho PL, de Valls Corsetti F, Iversen VV, Bjordal JM.

Abstract

STUDY DESIGN: Randomized crossover double-blinded placebo-controlled trial.

OBJECTIVE: To investigate if low level laser therapy (LLLT) can affect biceps muscle performance, fatigue development, and biochemical markers of post-exercise recovery.

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.

METHODS: Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes, l=810 nm, 200 mW power output, 30 seconds of irradiation, applied in 2 locations over the biceps of the non-dominant 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 (MVC) until exhaustion.

RESULTS: Active LLLT increased the number of repetitions by 14.5% (mean of 39.56, SD +/- 4.33 versus 34.56 +/- 5.64, p=0.037) and the elapsed time before exhaustion by 8.0% (p=0.034), when compared to the placebo treatment. The biochemical markers also indicated that recovery may be positively affected by LLLT as indicated by post-exercise blood lactate levels (p<0.01), Creatine Kinase (CK) activity (p=0.017), and C-Reactive Protein (CRP) levels (p=0.047) showing a faster recovery with LLLT application prior to the exercise.

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 post-exercise levels of blood lactate, CK, and CRP.

LEVEL OF EVIDENCE: Therapy, Level 1a.

J Orthop Sports Phys Ther, Epub 12 April 2010. doi:10.2519/jospt.2010.3294.

Eur J Appl Physiol. 2010 Apr;108(6):1083-8. Epub 2009 Dec 19.

Effect of low-level laser therapy (GaAs 904 nm) in skeletal muscle fatigue and biochemical markers of muscle damage in rats.

 

Leal Junior EC, Lopes-Martins RA, de Almeida P, Ramos L, Iversen VV, Bjordal JM. Section for Physiotherapy Science, Department of Public Health and Primary Health Care, University of Bergen (UiB), Kalfarveien 31, 5020 Bergen, Norway. ernesto.leal.junior@gmail.com

Abstract

We wanted to test if pre-exercise muscle irradiation with 904 nm laser affects the development of fatigue, blood lactate levels and creatine kinase (CK) activity in a rat model with tetanic contractions. Thirty male Wistar rats were divided into five groups receiving either one of four different laser doses (0.1, 0.3, 1.0 and 3.0 J) or a no-treatment control group. Laser irradiation was performed immediately before the first contraction for treated groups. Electrical stimulation was used to induce six tetanic tibial anterior muscle contractions with 10 min intervals between them. Contractions were stopped when the muscle force fell to 50% of the peak value for each contraction; blood samples were taken before the first and immediately after the sixth contraction. The relative peak forces for the sixth contraction were significantly better (P < 0.05) in the two laser groups irradiated with highest doses [151.27% (SD +/- 18.82) for 1.0 J, 144.84% (SD +/- 34.47) for 3.0 J and 82.25% (SD +/- 11.69) for the control group]. Similar significant (P < 0.05) increases in mean performed work during the sixth contraction for the 1.0 and 3.0 J groups were also observed. Blood lactate levels were significantly lower (P < 0.05) than the control group in all irradiated groups. All irradiated groups except the 3.0 J group had significantly lower post-exercise CK activity than the control group. We conclude that pre-exercise irradiation with a laser dose of 1.0 J and 904 nm wavelength significantly delays muscle fatigue and decreases post-exercise blood lactate and CK in this rat model.

Lasers Med Sci. 2010 Jan;25(1):115-20. Epub 2009 Jun 25.

 

Low-level laser therapy attenuates creatine kinase levels and apoptosis during forced swimming in rats.

Sussai DA, Carvalho Pde T, Dourado DM, Belchior AC, dos Reis FA, Pereira DM. Postgraduate Program in Health Science and Development in the Central Western Region, Universidade Federal do Mato Grosso do Sul (UFMS), Carandá Bosque, 79032-423 Campo Grande, MS, Brazil.

Abstract

Studies suggest that high-intensity physical exercise can cause damage to skeletal muscles, resulting in muscle soreness, fatigue, inflammatory processes and cell apoptosis. The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on a decrease in creatine kinase (CK) levels and cell apoptosis. Twenty male Wistar rats were randomly divided into two equal groups: group 1 (control), resistance swimming; group 2 (LLLT), resistance swimming with LLLT. They were subjected to a single application of indium gallium aluminum phosphide (InGaAlP) laser immediately following the exercise for 40 s at an output power of 100 mW, wavelength 660 nm and 133.3 J/cm(2). The groups were subdivided according to sample collection time: 24 h and 48 h. CK was measured before and both 24 h and 48 h after the test. Samples of the gastrocnemius muscle were processed to determine the presence of apoptosis using terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling. (There was a significant difference in CK levels between groups (P < 0.0001) as well as between the 24 h and 48 h levels in the control group, whereas there was no significant intra-group difference in the LLLT group at the same evaluation times. In the LLLT group there were 66.3 +/- 13.2 apoptotic cells after 24 h and 39.0 +/- 6.8 apoptotic cells after 48 h. The results suggest that LLLT influences the metabolic profile of animals subjected to fatigue by lowering serum levels of CK. This demonstrates that LLLT can act as a preventive tool against cell apoptosis experienced during high-intensity physical exercise.

Photomed Laser Surg. 2009 Dec;27(6):863-9.

Effects of low-level laser irradiation on rat skeletal muscle injury after eccentric exercise.

 

Liu XG, Zhou YJ, Liu TC, Yuan JQ.

Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.

Abstract

BACKGROUND AND OBJECTIVE: The effect of photobiomodulation on delayed onset muscle soreness remains unknown. This study represents the first investigation of this treatment using an animal model.

METHODS: Seventy-two Sprague-Dawley rats were randomly divided into five groups: sedentary control group, exercise control group and three exercise-plus-laser groups. Downhill running was used to induce muscle injury in the gastrocnemius muscle. He-Ne laser irradiations were administered to the injured muscles immediately and at 18 and 42 h after exercise in the three exercise-plus-laser groups at 12, 28, and 43 J/cm2, respectively. Histological examination and serum creatine kinase (CK), muscle superoxide dismutase (SOD) and malondialdehyde (MDA) analyses were done at 24 and 48 h after exercise.

RESULTS: The exercise control group exhibited a marked inflammation in the gastrocnemius muscle and significant elevations in serum CK activity and muscle MDA level after downhill running. He-Ne laser irradiation at 43 J/cm2 inhibited muscle inflammation, significantly enhanced muscle SOD activity and significantly reduced serum CK activity and muscle MDA level at both 24 and 48 h after exercise, whereas the irradiation at 12 or 28 J/cm2 slightly inhibited muscle inflammation and significantly reduced serum CK activity at 48 h after exercise only (P<0.05).

CONCLUSIONS: Low-level He-Ne laser therapy could exert therapeutic effects on eccentric exercise-induced rat muscle injury through enhancing muscle anti-oxidative capacity and reducing the inflammatory reaction. The photobiomodulation was dose-dependent, and the 43 J/cm2 dose was the most efficient among the doses used.

Exp Physiol. 2009 Jun 12. [Epub ahead of print]

Low-level laser irradiation promotes the recovery of atrophied gastrocnemius skeletal muscle in rat.

Nakano J, Kataoka H, Sakamoto J, Origuchi T, Okita M, Yoshimura T.

1 Nagasaki University Graduate School of Biomedical Sciences;

Low-level laser (LLL) irradiation promotes proliferation of muscle satellite cells, angiogenesis and expression of growth factors. Satellite cells, angiogenesis and growth factors play important roles in the regeneration of muscle. The objective of this study was to examine the effect of LLL irradiation on rat gastrocnemius muscle recovering from disuse muscle atrophy. Eight-week-old rats were subjected to hindlimb suspension for 2 weeks, after which they were released and recovered. During the recovery period, rats underwent daily LLL irradiation (Ga-Al-As; 830 nm; 60 mW; total, 180 sec) to the right gastrocnemius muscle through the skin. The untreated left gastrocnemius muscle served as the control. In conjunction with LLL irradiation, 5-bromo-2.deoxyuridine (BrdU) was injected subcutaneously for labeling of nuclei of proliferating cells. After 2 weeks, myofiber diameters of irradiated muscle increased in comparison with those of untreated muscle, but did’t recover back to normal levels. Additionally, in the superficial region of muscle, the number of capillaries and fibroblast growth factor levels in irradiated muscle exhibited meaningful elevation relative to those of untreated muscle. In the deep region of muscle, BrdU-positive nuclei of satellite cells and / or myofibers of irradiated muscle increased significantly relative to that of the untreated muscle. The results of this study suggested that LLL irradiation can promote recovery from disuse muscle atrophy in association with proliferation of satellite cells and angiogenesis.

Photomed Laser Surg. 2009 Aug;27(4):617-23.

Comparison between single-diode low-level laser therapy (LLLT) and LED multi-diode (cluster) therapy (LEDT) applications before high-intensity exercise.

Leal Junior EC, Lopes-Martins RA, Baroni BM, De Marchi T, Rossi RP, Grosselli D, Generosi RA, de Godoi V, Basso M, Mancalossi JL, Bjordal JM.

Laboratory of Human Movement, University of Caxias do Sul, Caxias do Sul, RS, Brazil. ecplealj@ucs.br

BACKGROUND DATA AND OBJECTIVE: There is anecdotal evidence that low-level laser therapy (LLLT) may affect the development of muscular fatigue, minor muscle damage, and recovery after heavy exercises. Although manufacturers claim that cluster probes (LEDT) maybe more effective than single-diode lasers in clinical settings, there is a lack of head-to-head comparisons in controlled trials. This study was designed to compare the effect of single-diode LLLT and cluster LEDT before heavy exercise.

MATERIALS AND METHODS: This was a randomized, placebo-controlled, double-blind cross-over study. Young male volleyball players (n = 8) were enrolled and asked to perform three Wingate cycle tests after 4 x 30 sec LLLT or LEDT pretreatment of the rectus femoris muscle with either (1) an active LEDT cluster-probe (660/850 nm, 10/30 mW), (2) a placebo cluster-probe with no output, and (3) a single-diode 810-nm 200-mW laser.

RESULTS: The active LEDT group had significantly decreased post-exercise creatine kinase (CK) levels (-18.88 +/- 41.48 U/L), compared to the placebo cluster group (26.88 +/- 15.18 U/L) (p < 0.05) and the active single-diode laser group (43.38 +/- 32.90 U/L) (p < 0.01). None of the pre-exercise LLLT or LEDT protocols enhanced performance on the Wingate tests or reduced post-exercise blood lactate levels. However, a non-significant tendency toward lower post-exercise blood lactate levels in the treated groups should be explored further.

CONCLUSION: In this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.

Exp Physiol. 2009 Jun 12. [Epub ahead of print]

Low-level laser irradiation promotes the recovery of atrophied gastrocnemius skeletal muscle in rat.

Nakano J, Kataoka H, Sakamoto J, Origuchi T, Okita M, Yoshimura T.

1 Nagasaki University Graduate School of Biomedical Sciences;

Low-level laser (LLL) irradiation promotes proliferation of muscle satellite cells, angiogenesis and expression of growth factors. Satellite cells, angiogenesis and growth factors play important roles in the regeneration of muscle. The objective of this study was to examine the effect of LLL irradiation on rat gastrocnemius muscle recovering from disuse muscle atrophy. Eight-week-old rats were subjected to hindlimb suspension for 2 weeks, after which they were released and recovered. During the recovery period, rats underwent daily LLL irradiation (Ga-Al-As; 830 nm; 60 mW; total, 180 sec) to the right gastrocnemius muscle through the skin. The untreated left gastrocnemius muscle served as the control. In conjunction with LLL irradiation, 5-bromo-2.deoxyuridine (BrdU) was injected subcutaneously for labeling of nuclei of proliferating cells. After 2 weeks, myofiber diameters of irradiated muscle increased in comparison with those of untreated muscle, but did’t recover back to normal levels. Additionally, in the superficial region of muscle, the number of capillaries and fibroblast growth factor levels in irradiated muscle exhibited meaningful elevation relative to those of untreated muscle. In the deep region of muscle, BrdU-positive nuclei of satellite cells and / or myofibers of irradiated muscle increased significantly relative to that of the untreated muscle. The results of this study suggested that LLL irradiation can promote recovery from disuse muscle atrophy in association with proliferation of satellite cells and angiogenesis.

Lasers Med Sci. 2009 Jun 25. [Epub ahead of print]

Low-level laser therapy attenuates creatine kinase levels and apoptosis during forced swimming in rats.

Sussai DA, Carvalho PD, Dourado DM, Belchior AC, Dos Reis FA, Pereira DM.

Postgraduate Program in Health Science and Development in the Central Western Region, Universidade Federal do Mato Grosso do Sul (UFMS), Rua Abricó do Pará, 146, Carandá Bosque, 79032-423, Campo Grande, MS, Brazil.

Studies suggest that high-intensity physical exercise can cause damage to skeletal muscles, resulting in muscle soreness, fatigue, inflammatory processes and cell apoptosis. The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on a decrease in creatine kinase (CK) levels and cell apoptosis. Twenty male Wistar rats were randomly divided into two equal groups: group 1 (control), resistance swimming; group 2 (LLLT), resistance swimming with LLLT. They were subjected to a single application of indium gallium aluminum phosphide (InGaAlP) laser immediately following the exercise for 40 s at an output power of 100 mW, wavelength 660 nm and 133.3 J/cm(2). The groups were subdivided according to sample collection time: 24 h and 48 h. CK was measured before and both 24 h and 48 h after the test. Samples of the gastrocnemius muscle were processed to determine the presence of apoptosis using terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling. (There was a significant difference in CK levels between groups (P < 0.0001) as well as between the 24 h and 48 h levels in the control group, whereas there was no significant intra-group difference in the LLLT group at the same evaluation times. In the LLLT group there were 66.3 +/- 13.2 apoptotic cells after 24 h and 39.0 +/- 6.8 apoptotic cells after 48 h. The results suggest that LLLT influences the metabolic profile of animals subjected to fatigue by lowering serum levels of CK. This demonstrates that LLLT can act as a preventive tool against cell apoptosis experienced during high-intensity physical exercise.

Photomed Laser Surg. 2008 Oct;26(5):419-24

Effect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans.

Leal Junior EC, Lopes-Martins RA, Dalan F, Ferrari M, Sbabo FM, Generosi RA, Baroni BM, Penna SC, Iversen VV, Bjordal JM.

Laboratory of Human Movement, University of Caxias do Sul, Caxias do Sul, RS, Brazil. ecplealj@ucs.br

OBJECTIVE: To investigate if development of skeletal muscle fatigue during repeated voluntary biceps contractions could be attenuated by low-level laser therapy (LLLT).

BACKGROUND DATA: Previous animal studies have indicated that LLLT can reduce oxidative stress and delay the onset of skeletal muscle fatigue.

MATERIALS AND METHODS: Twelve male professional volleyball players were entered into a randomized double-blind placebo-controlled trial, for two sessions (on day 1 and day 8) at a 1-wk interval, with both groups performing as many voluntary biceps contractions as possible, with a load of 75% of the maximal voluntary contraction force (MVC). At the second session on day 8, the groups were either given LLLT (655 nm) of 5 J at an energy density of 500 J/cm2 administered at each of four points along the middle of the biceps muscle belly, or placebo LLLT in the same manner immediately before the exercise session. The number of muscle contractions with 75% of MVC was counted by a blinded observer and blood lactate concentration was measured.

RESULTS: Compared to the first session (on day 1), the mean number of repetitions increased significantly by 8.5 repetitions (+/- 1.9) in the active LLLT group at the second session (on day 8), while in the placebo LLLT group the increase was only 2.7 repetitions (+/- 2.9) (p = 0.0001). At the second session, blood lactate levels increased from a pre-exercise mean of 2.4 mmol/L (+/- 0.5 mmol/L), to 3.6 mmol/L (+/- 0.5 mmol/L) in the placebo group, and to 3.8 mmol/L (+/- 0.4 mmol/L) in the active LLLT group after exercise, but this difference between groups was not statistically significant.

CONCLUSION: We conclude that LLLT appears to delay the onset of muscle fatigue and exhaustion by a local mechanism in spite of increased blood lactate levels.

Lasers Med Sci. 2008 Dec 5. [Epub ahead of print]

Effect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in athletes.

Leal Junior EC, Lopes-Martins RA, Baroni BM, De Marchi T, Taufer D, Manfro DS, Rech M, Danna V, Grosselli D, Generosi RA, Marcos RL, Ramos L, Bjordal JM.

Laboratory of Human Movement (LMH), Sports Medicine Institute (IME), University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas, 1130, 95070-560, Caxias do Sul, RS, Brazil, ecplealj@ucs.br.

Our aim was to investigate the immediate effects of bilateral, 830 nm, low-level laser therapy (LLLT) on high-intensity exercise and biochemical markers of skeletal muscle recovery, in a randomised, double-blind, placebo-controlled, crossover trial set in a sports physiotherapy clinic. Twenty male athletes (nine professional volleyball players and eleven adolescent soccer players) participated. Active LLLT (830 nm wavelength, 100 mW, spot size 0.0028 cm(2), 3-4 J per point) or an identical placebo LLLT was delivered to five points in the rectus femoris muscle (bilaterally). The main outcome measures were the work performed in the Wingate test: 30 s of maximum cycling with a load of 7.5% of body weight, and the measurement of blood lactate (BL) and creatine kinase (CK) levels before and after exercise. There was no significant difference in the work performed during the Wingate test (P > 0.05) between subjects given active LLLT and those given placebo LLLT. For volleyball athletes, the change in CK levels from before to after the exercise test was significantly lower (P = 0.0133) for those given active LLLT (2.52 U l(-1) +/- 7.04 U l(-1)) than for those given placebo LLLT (28.49 U l(-1) +/- 22.62 U l(-1)). For the soccer athletes, the change in blood lactate levels from before exercise to 15 min after exercise was significantly lower (P < 0.01) in the group subjected to active LLLT (8.55 mmol l(-1) +/- 2.14 mmol l(-1)) than in the group subjected to placebo LLLT (10.52 mmol l(-1) +/- 1.82 mmol l(-1)). LLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance. These findings suggest that LLLT may be of benefit in accelerating post-exercise recovery.

Photomed Laser Surg. 2008 Oct;26(5):419-24

Effect of 655-nm low-level laser therapy on exercise-induced skeletal muscle fatigue in humans.

Leal Junior EC, Lopes-Martins RA, Dalan F, Ferrari M, Sbabo FM, Generosi RA, Baroni BM, Penna SC, Iversen VV, Bjordal JM.

Laboratory of Human Movement, University of Caxias do Sul, Caxias do Sul, RS, Brazil. ecplealj@ucs.br

OBJECTIVE: To investigate if development of skeletal muscle fatigue during repeated voluntary biceps contractions could be attenuated by low-level laser therapy (LLLT).

BACKGROUND DATA: Previous animal studies have indicated that LLLT can reduce oxidative stress and delay the onset of skeletal muscle fatigue.

MATERIALS AND METHODS: Twelve male professional volleyball players were entered into a randomized double-blind placebo-controlled trial, for two sessions (on day 1 and day 8) at a 1-wk interval, with both groups performing as many voluntary biceps contractions as possible, with a load of 75% of the maximal voluntary contraction force (MVC). At the second session on day 8, the groups were either given LLLT (655 nm) of 5 J at an energy density of 500 J/cm2 administered at each of four points along the middle of the biceps muscle belly, or placebo LLLT in the same manner immediately before the exercise session. The number of muscle contractions with 75% of MVC was counted by a blinded observer and blood lactate concentration was measured.

RESULTS: Compared to the first session (on day 1), the mean number of repetitions increased significantly by 8.5 repetitions (+/- 1.9) in the active LLLT group at the second session (on day 8), while in the placebo LLLT group the increase was only 2.7 repetitions (+/- 2.9) (p = 0.0001). At the second session, blood lactate levels increased from a pre-exercise mean of 2.4 mmol/L (+/- 0.5 mmol/L), to 3.6 mmol/L (+/- 0.5 mmol/L) in the placebo group, and to 3.8 mmol/L (+/- 0.4 mmol/L) in the active LLLT group after exercise, but this difference between groups was not statistically significant.

CONCLUSION: We conclude that LLLT appears to delay the onset of muscle fatigue and exhaustion by a local mechanism in spite of increased blood lactate levels.

Lasers Med Sci. 2008 Dec 5. [Epub ahead of print]

Effect of 830 nm low-level laser therapy applied before high-intensity exercises on skeletal muscle recovery in athletes.

Leal Junior EC, Lopes-Martins RA, Baroni BM, De Marchi T, Taufer D, Manfro DS, Rech M, Danna V, Grosselli D, Generosi RA, Marcos RL, Ramos L, Bjordal JM.

Laboratory of Human Movement (LMH), Sports Medicine Institute (IME), University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas, 1130, 95070-560, Caxias do Sul, RS, Brazil, ecplealj@ucs.br

Our aim was to investigate the immediate effects of bilateral, 830 nm, low-level laser therapy (LLLT) on high-intensity exercise and biochemical markers of skeletal muscle recovery, in a randomised, double-blind, placebo-controlled, crossover trial set in a sports physiotherapy clinic. Twenty male athletes (nine professional volleyball players and eleven adolescent soccer players) participated. Active LLLT (830 nm wavelength, 100 mW, spot size 0.0028 cm(2), 3-4 J per point) or an identical placebo LLLT was delivered to five points in the rectus femoris muscle (bilaterally). The main outcome measures were the work performed in the Wingate test: 30 s of maximum cycling with a load of 7.5% of body weight, and the measurement of blood lactate (BL) and creatine kinase (CK) levels before and after exercise. There was no significant difference in the work performed during the Wingate test (P > 0.05) between subjects given active LLLT and those given placebo LLLT. For volleyball athletes, the change in CK levels from before to after the exercise test was significantly lower (P = 0.0133) for those given active LLLT (2.52 U l(-1) +/- 7.04 U l(-1)) than for those given placebo LLLT (28.49 U l(-1) +/- 22.62 U l(-1)). For the soccer athletes, the change in blood lactate levels from before exercise to 15 min after exercise was significantly lower (P < 0.01) in the group subjected to active LLLT (8.55 mmol l(-1) +/- 2.14 mmol l(-1)) than in the group subjected to placebo LLLT (10.52 mmol l(-1) +/- 1.82 mmol l(-1)). LLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance. These findings suggest that LLLT may be of benefit in accelerating post-exercise recovery.

J Appl Physiol. 2006 Jul;101(1):283-8. Epub 2006 Apr 20.

 

Effect of low-level laser (Ga-Al-As 655 nm) on skeletal muscle fatigue induced by electrical stimulation in rats.

 

Lopes-Martins RA, Marcos RL, Leonardo PS, Prianti AC Jr, Muscará MN, Aimbire F, Frigo L, Iversen VV, Bjordal JM.

Department of Pharmacology, Laboratory of Biochemical Pharmacology of Free Radicals, Institute of Biomedical Sciences, University of São Paulo, Brazil. rmartins@icb.usp.br

Abstract

We investigated whether low-level laser therapy (LLLT) can reduce muscular fatigue during tetanic contractions in rats. Thirty-two male Wistar rats were divided into four groups receiving either one of three different LLLT doses (0.5, 1.0, and 2.5 J/cm2) or a no-treatment control group. Electrical stimulation was used to induce six tetanic muscle contractions in the tibial anterior muscle. Contractions were stopped when the muscle force fell to 50% of the initial value for each contraction (T50%). There was no significant difference between the 2.5 J/cm2 laser-irradiated group and the control group in mean T50% values. Laser-irradiated groups (0.5 and 1.0 J/cm2) had significantly longer T50% values than the control group. The relative peak force for the sixth contraction in the laser-irradiated groups were significantly higher at 92.2% (SD 12.6) for 0.5 J/cm2, 83.2% (SD 20.5) for 1.0 J/cm2, and 82.9% (SD 18.3) for 2.5 J/cm2 than for the control group [50% (SD 15)]. Laser groups receiving 0.5 and 1.0 J/cm2 showed significant increases in mean performed work compared with both the control group and their first contraction values. Muscle damage was indirectly measured by creatine kinase levels in plasma. A distinct dose-response pattern was found in which 1.0 and 2.5 J/cm2 LLLT groups had significantly lower creatine kinase levels than the 0.5 J/cm2 LLLT group and the control group. We conclude that LLLT doses of 0.5 and 1.0 J/cm2 can prevent development of muscular fatigue in rats during repeated tetanic contractions.

Photomed Laser Surg. 2006 Apr;24(2):111-20.

Photoengineering of tissue repair in skeletal and cardiac muscles.

Oron U.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel.oronu@post.tau.ac.il

This review discusses the application of He-Ne laser irradiation to injured muscles at optimal power densities and optimal timing, which was found to significantly enhance (twofold) muscle regeneration in rats and, even more, in the cold-blooded toads. Multiple and frequent (daily) application of the laser in the toad model was found to be less effective than irradiation on alternate days. It was found that in the ischemia/reperfusion type of injury in the skeletal leg muscles (3 h of ischemia), infrared Ga-Al-As laser irradiation reduced muscle degeneration, increased the cytoprotective heat shock proteins (HSP-70i) content, and produced a twofold increase in total antioxidants. In vitro studies on myogenic satellite cells (SC) revealed that phototherapy restored their proliferation. Phototherapy induced mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) phosphorylation in these cells, probably by specific receptor phosphorylation. Cell cycle entry and the accumulation of satellite cells around isolated single myofibers cultured in vitro was also stimulated by phototherapy. Phototherapy also had beneficial effects on mouse, rat, dog and pig ischemic heart models. In these models, it was found that phototherapy markedly and significantly reduced (50-70%) the scar tissue formed after induction of myocardial infarction (MI). The phototherapeutic effect was associated with reduction of ventricular dilatation, preservation of mitochondria and elevation of HSP- 70i and ATP in the infarcted zone. It is concluded that phototherapy using the correct parameters and timing has a markedly beneficial effect on repair processes after injury or ischemia in skeletal and heart muscles. This phenomenon may have clinical applications.

J Appl Physiol. 2006 Jul;101(1):283-8. Epub 2006 Apr 20.

Effect of low-level laser (Ga-Al-As 655 nm) on skeletal muscle fatigue induced by electrical stimulation in rats.

Lopes-Martins RA, Marcos RL, Leonardo PS, Prianti AC Jr, Muscará MN, Aimbire F, Frigo L, Iversen VV, Bjordal JM.

Department of Pharmacology, Laboratory of Biochemical Pharmacology of Free Radicals, Institute of Biomedical Sciences, University of São Paulo, Brazil. rmartins@icb.usp.br

We investigated whether low-level laser therapy (LLLT) can reduce muscular fatigue during tetanic contractions in rats. Thirty-two male Wistar rats were divided into four groups receiving either one of three different LLLT doses (0.5, 1.0, and 2.5 J/cm2) or a no-treatment control group. Electrical stimulation was used to induce six tetanic muscle contractions in the tibial anterior muscle. Contractions were stopped when the muscle force fell to 50% of the initial value for each contraction (T50%). There was no significant difference between the 2.5 J/cm2 laser-irradiated group and the control group in mean T50% values. Laser-irradiated groups (0.5 and 1.0 J/cm2) had significantly longer T50% values than the control group. The relative peak force for the sixth contraction in the laser-irradiated groups were significantly higher at 92.2% (SD 12.6) for 0.5 J/cm2, 83.2% (SD 20.5) for 1.0 J/cm2, and 82.9% (SD 18.3) for 2.5 J/cm2 than for the control group [50% (SD 15)]. Laser groups receiving 0.5 and 1.0 J/cm2 showed significant increases in mean performed work compared with both the control group and their first contraction values. Muscle damage was indirectly measured by creatine kinase levels in plasma. A distinct dose-response pattern was found in which 1.0 and 2.5 J/cm2 LLLT groups had significantly lower creatine kinase levels than the 0.5 J/cm2 LLLT group and the control group. We conclude that LLLT doses of 0.5 and 1.0 J/cm2 can prevent development of muscular fatigue in rats during repeated tetanic contractions.

Photomed Laser Surg. 2005 Jun;23(3):273-7

Protection of skeletal muscles from ischemic injury: low-level laser therapy increases antioxidant activity.

Avni D, Levkovitz S, Maltz L, Oron U.

Department of Zoology, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.

OBJECTIVE: The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on ischemic-reperfusion (I-R) injury in the gastrocnemius muscle of the rat.

BACKGROUND DATA: Ischemic injury in skeletal muscle is initiated during hypoxia and is aggravated by reoxygenation during blood reperfusion and accumulation of cytotoxic reactive oxygen superoxides. LLLT has been found to biostimulate various biological processes, such as attenuation of ischemic injury in the heart.

MATERIALS AND METHODS: The injury was induced in the gastrocnemius muscles of 106 rats by complete occlusion of the blood supply for 3 h, followed by reperfusion. Another group of intact rats served to investigate the effect of LLLT on intact nonischemic muscles. Creatine phosphokinase, acid phosphatase, and heat shock protein were determined 7 days after I-R injury and antioxidant levels 2 h after reperfusion.

RESULTS: Laser irradiation (Ga-As, 810 nm) was applied to the muscles immediately and 1 h following blood supply occlusion. It was found that laser irradiation markedly protects skeletal muscles from degeneration following acute I-R injury. This was evident by significantly (p < 0.05) higher content of creatine phosphokinase activity and lower (p < 0.05) activity of acid phosphatase in the LLLT-treated muscles relative to the injured non-irradiated ones. The content of antioxidants and heat shock proteins was also higher (p < 0.05) in the LLLT-treated muscles relative to that of injured non-irradiated muscles.

CONCLUSION: The present study describes for the first time the ability of LLLT to significantly prevent degeneration following ischemia/reperfusion injury in skeletal muscles, probably by induction of synthesis of antioxidants and other cytoprotective proteins, such as hsp-70i. The elevation of antioxidants was also evident in intact muscle following LLLT. The above phenomenon may also be of clinical relevance in scheduled surgery or microsurgery requiring extended tourniquet applications to skeletal muscle followed by reperfusion.

Lasers Med Sci. 2006 Dec;21(4):238-44. Epub 2006 Oct 11

Low-level laser therapy can reduce lipopolysaccharide-induced contractile force dysfunction and TNF-alpha levels in rat diaphragm muscle.

Aimbire F, Lopes-Martins RA, Castro-Faria-Neto HC, Albertini R, Chavantes MC, Pacheco MT, Leonardo PS, Iversen VV, Bjordal JM.

Research Group of Animal Experimental, IP & D UNIVAP R. Shishima Hifumi, 2911, 12240-000, São José dos Campos, SP, Brazil.

Our objective was to investigate if low-level laser therapy (LLLT) could improve respiratory function and inhibit tumor necrosis factor (TNF-alpha) release into the diaphragm muscle of rats after an intravenous injection of lipopolysaccharide (LPS) (5 mg/kg). We randomly divided Wistar rats in a control group without LPS injection, and LPS groups receiving either (a) no therapy, (b) four sessions in 24 h with diode Ga-AsI-Al laser of 650 nm and a total dose of 5.2 J/cm2, or (c) an intravenous injection (1.25 mg/kg) of the TNF-alpha inhibitor chlorpromazine (CPZ). LPS injection reduced maximal force by electrical stimulation of diaphragm muscle from 24.15+/-0.87 N in controls, but the addition of LLLT partly inhibited this reduction (LPS only: 15.01+/-1.1 N vs LPS+LLLT: 18.84+/-0.73 N, P<0.05). In addition, this dose of LLLT and CPZ significantly (P<0.05 and P<0.01, respectively) reduced TNF-alpha concentrations in diaphragm muscle when compared to the untreated control group.

J Cell Sci. 2002 Apr 1;115(Pt 7):1461-9.

 

Low-energy laser irradiation promotes the survival and cell cycle entry of skeletal muscle satellite cells.

Shefer G, Partridge TA, Heslop L, Gross JG, Oron U, Halevy O.

Department of Animal Sciences, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100, Israel.

Low energy laser irradiation (LELI) has been shown to promote skeletal muscle cell activation and proliferation in primary cultures of satellite cells as well as in myogenic cell lines. Here, we have extended these studies to isolated myofibers. These constitute the minimum viable functional unit of the skeletal muscle, thus providing a close model of in vivo regeneration of muscle tissue. We show that LELI stimulates cell cycle entry and the accumulation of satellite cells around isolated single fibers grown under serum-free conditions and that these effects act synergistically with the addition of serum. Moreover, for the first time we show that LELI promotes the survival of fibers and their adjacent cells, as well as cultured myogenic cells, under serum-free conditions that normally lead to apoptosis. In both systems, expression of the anti-apoptotic protein Bcl-2 was markedly increased, whereas expression of the pro-apoptotic protein BAX was reduced. In culture, these changes were accompanied by a reduction in the expression of p53 and the cyclin-dependent kinase inhibitor p21, reflecting the small decrease in viable cells 24 hours after irradiation. These findings implicate regulation of these factors as part of the protective role of LELI against apoptosis. Taken together, our findings are of critical importance in attempts to improve muscle regeneration following injury.

Anat Rec. 1995 Jan;241(1):123-8.

Regeneration in denervated toad (Bufo viridis) gastrocnemius muscle and the promotion of the process by low energy laser irradiation.

Bibikova A, Oron U.

Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.

BACKGROUND: It is known that while denervated skeletal muscles have the ability to regenerate, maturation of regenerated myofibres does not take place under these conditions. Denervation also causes elevation of “invasive” and satellite cells, but the role of these cells in the regeneration process after injury to the denervated muscle is still unknown. Low energy lasers have recently been found to modulate and accelerate physiological processes in cells. The aim of the present study was to compare regeneration in denervated and innervated amphibian muscles and to investigate whether this process in denervated muscles can be stimulated by low energy laser irradiation prior to injury in these muscles.

METHODS: Denervated gastrocnemius muscles of toads were irradiated with He-Ne laser (6.0 mW, 31.2 J/cm2) 7 days postdenervation (control muscle received red light irradiation at the same wavelength). Nine days after denervation cold injury was performed on the site of irradiation of both groups of muscles. At 14 days postinjury all muscles were removed and processed for histology and histomorphometric analysis of mononucleated cells, myotubes, and young myofibres in the regenerated zone.

RESULTS: The volume fraction (percent of total injured zone) of the various histological structures in the injured zones 14 days after cold injury in the denervated (9 days prior to injury) muscles did not differ from innervated injured muscles at the same time interval postinjury. The mononucleated cells and myotubes in the laser irradiated muscles comprised 49 +/- 4% and 6 +/- 1% of the injured area, respectively, which was significantly lower than their volume fraction (67 +/- 2% and 11 +/- 2%, respectively) in the control muscles. The young myofibres populated 34 +/- 4% of the total injured area in the denervated and laser irradiated muscles which was significantly higher than their volume fraction (12 +/- 2%) in control denervated muscles.

CONCLUSIONS: It is concluded that initial stages of regeneration can also take place in skeletal denervated and injured muscles of amphibians. The kinetics of the regeneration process are identical in denervated and innervated muscles. The process of regeneration in denervated muscles can be markedly enhanced if the muscle is irradiated by low energy laser prior to injury, probably by activation (stimulation of proliferation and/or differentiation) cells in the muscles that are “recruited” and participate in the process of regeneration.

Lasers Med Sci. 2001;16(1):44-51

Dose-dependency of low-energy HeNe laser effect in regeneration of skeletal muscle in mice.

Amaral AC, Parizotto NA, Salvini TF.

Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos/SP, Brasil.

We evaluated the effect on mice skeletal muscle regeneration of different doses (2.6, 8.4, and 25 J/cm2) of HeNe laser (lambda 632.8 nm; power, 2.6 mW; spot size, 0.007 cm2) applied directly to intact skin of injured muscle. Muscle injury was induced in both right and left Tibialis anterior (TA) muscles by ACL myotoxin (5 mg/kg). Right TA muscles were irradiated daily for 5 days while contralateral muscles received a sham treatment. Only the 2.6 J/cm2 dose resulted in changes such as increased mitochondrial density and muscle fibre in the TA muscles as compared to sham groups (3280 +/- 704 microns 2 versus 2110 +/- 657 microns 2, p = 0.02). We concluded that the HeNe effect on mouse muscle regeneration is dose-specific: only 2.6 J/cm2 increased muscle fibre area and mitochondrial density.

Radiats Biol Radioecol. 2002 May-Jun;42(3):315-21.

Histogenetic, metabolic, and immunologic aspects of the effect of infrared laser radiation on injured skeletal muscles from irradiated and nonirradiated rats.

[Article in Russian]

Zubkova SM, Buliakova NV, Mikha?lik LV, Varakina NI, Azarova VS.

Russian Research Center of Rehabilitative Medicine and Balneology, Ministry of Health of Russia, Moscow, 121099, Russia.

Using biochemical, histological, morphometric and cytogenetic methods, it was shown that low-intensive infrared laser radiation (total dose 3.6 J/cm2), applied to the injured rat skeletal muscles, stimulated metabolism and regeneration more efficiently in the muscles locally exposed to 20 Gy X-rays compared to the unexposed muscles. The laser irradiation promoted postradiative recovery in bone marrow cells, but did not provide normalization in thymus lymphocyte activity.

Vopr Kurortol Fizioter Lech Fiz Kult. 2000 Nov-Dec;(6):8-11.

Experimental study of the effect of pulsed infrared laser radiation on skeletal muscle regeneration after mechanical trauma.

[Article in Russian]

Buliakova NV, Zubkova SM, Azarova VS, Mikha?lik LV, Varakina NI.

Impulse infrared laser radiation (0.89 microm) was examined for effect on regeneration of cross-cut musculus gastrocnemius in adult rats (ten 3-min exposures, 2-3 procedures weekly for one month after the operation, modulating frequency 10 Hz, total course dose 3.6 J/cm2). Histological, morphometric and biochemical parameters of muscular regenerates as well as biochemical serum indices show enhanced regeneration of the skeletal muscle. Formation of the muscular organ ends earlier vs untreated muscles. This was accompanied with more active sclerotization of the muscular regenerate.

Vopr Kurortol Fizioter Lech Fiz Kult. 1998 Nov-Dec;(6):11-6.

A comparative analysis of the action of red and infrared laser radiation and ultrasound on the regeneration of locally irradiated skeletal muscle and on immune system function in the rat.

[Article in Russian]

Subkova SM, Buliakova NV, Mikha?lik LV, Varakina NI, Azarova VS.

The study was made of a regeneration ability of the rat skeletal muscle which had been mechanically injured and exposed to a 20 Gy irradiation, of the thymus and bone marrow condition after local exposure of the muscle to red and infrared laser radiation and ultrasound. These factors were found to stimulate regeneration of the injured soft tissues and to reduce cytogenetic damage to bone marrow cells in the irradiated zone under growing immunosuppression. The stimulation was most potent in prolonged exposure to the ultrasound.

J Clin Laser Med Surg. 1996 Dec;14(6):375-80.

Delayed-onset muscle soreness: lack of effect of combined phototherapy/low-intensity laser therapy at low pulse repetition rates.

Craig JA, Barlas P, Baxter GD, Walsh DM, Allen JM.

Rehabilitation Sciences Research Group, School of Health Sciences, University of Ulster, Jordanstown, N. Ireland.

A double-blind, placebo-controlled study using male subjects (n = 60), was conducted to investigate the efficacy of three different frequencies of combined phototherapy/low-intensity laser therapy (CLILT) in alleviating the signs and symptoms of delayed-onset muscle soreness (DOMS). The study was approved by the University’s ethical committee. After screening for relevant pathologies, recent analgesic or steroid drug usage, current pain, diabetes, or current involvement in regular weight-training activities, subjects were randomly allocated to one of five experimental groups: Control, Placebo, or 2.5-Hz, 5-Hz, or 20-Hz CLILT groups (660-950 nm; 31.7 J/cm2; pulsed at the given frequencies for a duration of 12 min; n = 12 all groups). Once baseline measurements were obtained, DOMS was induced in the nondominant arm, which was exercised in a standardized fashion until exhaustion, using repeated eccentric contractions of the elbow flexors. The procedure was repeated twice more to ensure exhaustion was achieved, after which subjects were treated according to group allocation. In the CLILT/placebo groups, the treatment head was applied directly to the affected arm at the level of the musculotendinous junction. Subjects returned on two consecutive days for further treatment and assessment. The range of variables used to assess DOMS included range of movement (universal goniometer), mechanical pain threshold/tenderness (algometer) and pain (visual analogue scale and McGill Pain Questionnaire). Measurements were taken before and after treatment on each day, except for the McGill Pain questionnaire, which was completed at the end of the study. Analysis of results using repeated measures and one-factor analysis of variance with relevant post hoc tests showed significant changes in ranges of movement accompanied by increases in subjective pain and tenderness for all groups over time (p = 0.0001); however, such analysis failed to show any significant differences between groups on any of the days. These results thus provide no convincing evidence for any putative hypoalgesic effect of CLILT upon DOMS at the parameters used here.

Biull Eksp Biol Med. 1989 Mar;107(3):345-7.

Effect of helium-neon laser rays on the processes of postradiation recovery in the skeletal muscles of old rats.

[Article in Russian]

Buliakova NV.

The present experiments were conducted to determine the stimulant effect of helium-neon laser on the postradiation recovery in irradiated uninjured skeletal muscle of rats aged 2-2.5. This was indicated by a restored ability of the muscle for posttraumatic regeneration. The both hind rat legs were exposed to local irradiation of 20 Gy and following laser therapy (8-9 procedures at 3 min each, impulsive or continuous one). Then both musculus gastrocnemius were cut across 30 days after irradiation. It was shown that laser therapy employed before injury of the irradiated muscle accelerated fibrin resorption and improved connective tissue, but slightly stimulated muscular tissue. Impulse laser therapy was more favourable for state of skin and healing of the skin wound after irradiation.