Laser therapy musculoskeletal, sports injuries

Photobiomodulation, Photomedicine, and Laser Surgery Volume XX, Number XX, 2020 ª Mary Ann Liebert, Inc. Pp. 1–8 DOI: 10.1089/photob.2020.4820

Dose–Response Effect of Photobiomodulation Therapy on Muscle Performance and Fatigue During a Multiple-Set Knee Extension Exercise: A Randomized, Crossover, Double-Blind Placebo-Controlled Trial

Mateus Rossato, PhD,1,2 Rodolfo Andre´ Dellagrana, PhD,1,3 Raphael Luiz Sakugawa, MS,1
Bruno Manfredini Baroni, PhD,4 and Fernando Diefenthaeler, PhD1

Objective: The aim of this study was to identify the best energy dose of photobiomodulation therapy (PBMT) able to improve muscle performance and reduce fatigue during multiple-set knee extension exercise. 

Methods: Eighteen physically active men participated in this study. Each participant performed an isokinetic exercise protocol (5 sets of 10 knee extension repetitions, maximum contractions at 60$s -1 ) in 6 sessions, 1 week apart. Control condition (no PBMT/placebo treatments) was applied at the first and sixth sessions. Placebo or PBMT with 135, 270, or 540 J/quadriceps was randomly applied from the second to fifth sessions. Placebo/PBMT treatments were always applied at two moments: 6 h before and immediately before exercise. The isometric and isokinetic concentric peak torques were assessed before and after the exercise protocol. 

Results: The knee extension exercise performance (total work performed during exercise) was not affected by PBMT (135, 270, and 540 J) compared with placebo treatment. However, all PBMT treatments (135, 270, and 540 J) led to lower percentage drop compared with placebo and control conditions on isometric peak torque
(IPT), concentric peak torque (CPT), and concentric work (W). All PBMT doses led to possibly positive or likely positive effects on IPT, CPT, and W compared with placebo.

Conclusions: Our findings demonstrate that PBMT with 135, 270, and 540 J applied at two moments (6 h before and immediately before exercise) was able to produce the same total work

Photomedicine and Laser Surgery Volume 32, Number 2, 2014 ª Mary Ann Liebert, Inc. Pp. 106–112 DOI: 10.1089/pho.2013.3617

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

Filipe Abdalla dos Reis, PT, PhD,1,2 Baldomero Antonio Kato da Silva, PT, PhD,3 Erica Martinho Salvador Laraia, PT, MSc,1 Rhaiza Marques de Melo, PT,4 Patrı´cia Henrique Silva, PT,4 Ernesto Cesar Pinto Leal-Junior, PT, PhD,5 and Paulo de Tarso Camillo de Carvalho, PT, PhD5


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 cm2 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/cm2 , 21.42 W/cm2 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.

Photomedicine and Laser Surgery Volume 31, Number 10, 2013

Protective Effect of Laser Phototherapy on Acetylcholine Receptors and Creatine Kinase Activity in Denervated Muscle

Shimon Rochkind, MD,1,2 and Asher Shainberg, PhD1

Objective: This study was designed to assess the status of skeletal muscles after laser treatment during long-term denervation processes, by investigating changes in the level of acetylcholine receptors (AChR) and creatine kinase (CK) activity in the denervated gastrocnemius muscle of the rat.

Background data: Progressive muscle atrophy is common in patients with severe peripheral nerve injury. Denervated muscles can account for significant differences in the extent of AChR and CK activity during the denervation period.

Methods: The study was conducted on 96 rats: 48 that received laser treatment and 48 untreated controls. The gastrocnemius muscle was denervated by removing a 10mm segment of the sciatic nerve. Low power laser irradiation was delivered transcutaneously to the right gastrocnemius muscle (HeNe continuous wave [CW] laser, 632.8 nm, 35mW, 30 min) for 14 consecutive days. Under general anesthesia, the rats were euthanized at seven time points: day 7 (n = 10), day 14 (n = 10), day 21 (n = 10), day 30 (n = 5), day 60 (n = 4), day 120 (n = 5), and day 210 (n = 4), with and without laser treatment, respectively. AChR was quantified by the 125I-a-bungarotoxin. CK activity was measured by a specific spectrophotometric method.

Results: Laser treatment had a significant therapeutic effect on the denervated muscle during the first 21 days for AChR and the first 30 days for CK activity.

Conclusion: In the early stages of muscle atrophy, laser phototherapy may preserve the denervated muscle by maintaining CK activity and the amount of AChR.

Photomedicine and Laser Surgery Volume 31, Number 10, 2013

Effect of Low-Level Laser Therapy (808 nm) in Skeletal Muscle After Resistance Exercise Training in Rats

Tatiane Patrocinio, PhD,1 Andre Cabral Sardim,2 Livia Assis, PhD,2 Kelly Rossetti Fernandes, MS,2
Natalia Rodrigues, PhD,1 and Ana Claudia Muniz Renno, PhD1

Objective: The aim of this study was to evaluate the effects of 808nm laser applied after a resistance training protocol, on biochemical markers and the morphology of skeletal muscle in rats.

Background Data: Strenuous physical activity results in fatigue and decreased muscle strength, impaired motor control, and muscle pain. Many biochemical and biophysical interventions have been studied in an attempt to accelerate the recovery process of muscle fatigue. Among these, low-level laser therapy (LLLT) has been demonstrated to be effective in increasing skeletal muscle performance in in vivo studies and in clinical trials. However, little is known about the effects of LLLT on muscle performance after resistance training.

Methods: Thirty Wistar rats were randomly divided into three groups: control group (CG), trained group (TG), and trained and laser-irradiated group (TGL).

The resistance training program was performed three times per week for 5 weeks, and consisted of a climbing exercise, with weights attached to the tail of the animal. Furthermore, laser irradiation was performed in the middle region of tibialis anterior (TA) muscle of both legs, after the exercise protocol.

Results: Analysis demonstrated that TGL demonstrated significantly reduced resting lactate level and decreased muscle glycogen depletion than the animals that were exercised only, and significantly increased the cross-section area of TA muscle fibers compared with thoseo in the other groups.

Conclusion: These results suggest that LLLT could be an effective therapeutic approach in increasing muscle performance during a resistance exercise protocol.

Effect of 655-nm Low-Level Laser Therapy on Exercise-Induced Skeletal Muscle Fatigue in Humans

Ernesto Cesar Pinto Leal Junior, M.Sc.,1,2,3 Rodrigo �lvaro Brandão Lopes-Martins, Ph.D.,4, Dalan, P.T.,5 Maurício Ferrari, P.T.,5 Fernando Montanari Sbabo, P.T.,5, Rafael Abeche Generosi, P.E.,6 Bruno Manfredini Baroni, P.T.,5, Sócrates Calvoso Penna, Ph.D.,4 Vegard V. Iversen, Ph.D.,8 and Jan Magnus Bjordal, Ph.D.3,7

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.

Methods: Twelve male professional volleyball players were entered into a randomized doubleblind 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.

Photomedicine and Laser Surgery Volume 32, Number 12, 2014 ª Mary Ann Liebert, Inc. Pp. 678–685 DOI: 10.1089/pho.2014.3812
Use of Low-Level Laser Therapy (808 nm) to Muscle Fatigue Resistance: A Randomized Double-Blind Crossover Trial
Wouber He´rickson de Brito Vieira, PhD,1 Raphael Machado Bezerra,1 Renata Alencar Saldanha Queiroz,1 Nı´cia Farias Braga Maciel,1 Nivaldo Antonio Parizotto, PhD,2,3 and Cleber Ferraresi, PhD2,3
Objective: The purpose of this study was to investigate whether low-level laser (light) therapy (LLLT) can provide fatigue resistance via maximum repetitions (RM) with an isokinetic dynamometer, and decrease electromyography fatigue index (EFI).
Background data: LLLT has been used to increase muscle performance when applied before or after intense exercises.
Materials and methods: This study was a randomized, doubleblind, crossover trial with placebo. Seven young men (21 – 3 years of age) who were clinically healthy, were allocated into two groups: active laser (LLLT) and placebo laser (Placebo). Both groups were assessed at baseline, at one training session, and at the end of this study. Baseline and final assessments recorded the number of RM of knee flexion-extensions using an isokinetic dynamometer at 60 degrees/sec in conjunction with EFI recorded by median frequency. The training sessions consisted of three sets of 20 RM of knee flexionextensions using an isokinetic dynamometer at 60 degrees/sec plus LLLT (808 nm, 100 mW, 4 J), or placebo, applied to quadriceps femoris muscles between sets, and after the last series of this exercise. After 1 week (washout period), all volunteers were exchanged among groups and then all assessments were repeated.
Results: LLLT group increased RM (52%; p = 0.002) with a small EFI for the vastus medialis ( p = 0.004) and rectus femoris ( p = 0.004).
Conclusions: These results suggest an increased muscle fatigue resistance when LLLT is applied during rest intervals, and after the last series of intense exercises.


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