Pre-Exercise Infrared Low-Level Laser Therapy (810 nm) in Skeletal Muscle Performance and Postexercise Recovery in Humans, What Is the Optimal Dose? A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Fatigue Alleviation by Low-Level Laser Preexposure in Ischemic Neuromuscular Electrical Stimulation

PURPOSE

Despite its susceptibility to muscle fatigue, combined neuromuscular electrical stimulation (NMES) and blood flow restriction (BFR) are effective regimens for managing muscle atrophy when traditional resistance exercises are not feasible. This study investigated the potential of low-level laser therapy (LLLT) in reducing muscle fatigue after the application of combined NMES and BFR.

METHODS

Thirty-six healthy adults were divided into control and LLLT groups. The LLLT group received 60 J of 850-nm wavelength LLLT before a training program of combined NMES and BFR of the nondominant extensor carpi radialis longus (ECRL). The control group followed the same protocol but received sham laser therapy. Assessments included maximal voluntary contraction, ECRL mechanical properties, and isometric force tracking for wrist extension.

RESULTS

The LLLT group exhibited a smaller normalized difference in maximal voluntary contraction decrement (-4.01 ± 4.88%) than the control group (-23.85 ± 7.12%) ( P < 0.001). The LLLT group demonstrated a smaller decrease in muscle stiffness of the ECRL compared with the control group, characterized by the smaller normalized changes in frequency ( P = 0.002), stiffness ( P = 0.002), and relaxation measures ( P = 0.011) of mechanical oscillation waves. Unlike the control group, the LLLT group exhibited a smaller posttest increase in force fluctuations during force tracking ( P = 0.014), linked to the predominant recruitment of low-threshold MU ( P < 0.001) without fatigue-related increases in the discharge variability of high-threshold MU ( P > 0.05).

CONCLUSIONS

LLLT preexposure reduces fatigue after combined NMES and BFR, preserving force generation, muscle stiffness, and force scaling. The functional benefits are achieved through fatigue-resistant activation strategies of motor unit recruitment and rate coding.

The Effects of Near-Infrared Phototherapy Preirradiation on Lower-Limb Muscle Strength and Injury After Exercise: A Systematic Review and Meta-analysis

OBJECTIVE

To assess near-infrared preirradiation effects on postexercise lower-limb muscle damage and function and determine optimal dosage.

DATA SOURCES

PubMed, Embase, Cochrane Library, EBSCO, Web of Science, China National Knowledge Infrastructure, and Wanfang Data were systematically searched (2009-2023).

STUDY SELECTION

Randomized controlled trials of near-infrared preirradiation on lower-limb muscles after fatigue exercise were incorporated into the meta-analysis. Out of 4550 articles screened, 21 met inclusion criteria.

DATA EXTRACTION

The included studies' characteristics were independently extracted by 2 authors, with discrepancies resolved through discussion or by a third author. Quality assessment was performed using the Cochrane risk of bias tool and the Grading of Recommendations, Assessment, Development, and Evaluation System.

DATA SYNTHESIS

In 21 studies, near-infrared preirradiation on lower-limb muscles inhibited the decline in peak torque (standardized mean difference [SMD], 1.33; 95% confidence interval [CI], 1.08-1.59; p<.001; increasing 27.97±4.87N·m), reduced blood lactate (SMD, -0.2; 95% CI, -0.37 to -0.03; p=.272; decreasing 0.54±0.42mmol/L), decreased creatine kinase (SMD, -2.11; 95% CI, -2.57 to -1.65; p<.001; decreasing 160.07±27.96U/L), and reduced delayed-onset muscle soreness (SMD, -0.53; 95% CI, -0.81 to 0.24; p<.001). Using a 24-hour cutoff revealed 2 trends: treatment effectiveness depended on power and energy density, with optimal effects at 24.16 J/cm2 and 275 J/cm2 for energy, and 36.81 mW/cm2 and 5495 mW/cm2 for power. Noting that out of 21 studies, 19 are from Brazil, 1 from the United States, and 1 from Australia, and the results exhibit high heterogeneity.

CONCLUSIONS

Although we would have preferred a more geographic dispersion of laboratories, our findings indicate that near-infrared preirradiation mitigates peak torque decline in lower-limb muscles. Influenced by energy and power density with a 24-hour threshold, optimal energy and power densities are observed at 24.16 J/cm2, 275 J/cm2, 36.81 mW/cm2, and 5495 mW/cm2, respectively. Laser preirradiation also reduces blood lactate, creatine kinase, and delayed-onset muscle soreness.

Influence of Intravascular Laser Irradiation of Blood (ILIB) on inflammatory cytokines and nitric oxide in vivo: a systematic review

The use of Intravascular Laser Irradiation of Blood (ILIB) as a treatment or adjunct tool has been used around the world since the 1980s. So that more professionals can deliver benefits to their patients in different areas of health, it is necessary to understand in depth the mechanisms of laser action at the molecular level, for correct indication and success in the treatment. To analyze works that evaluated the influence of ILIB on inflammatory cytokines and nitric oxide (NO) in animals and humans. The literature search was carried out between February and April 2023 in Pubmed, Medline, Web of Science, SciELO, Lilacs database. The risk of bias was assessed using the bias table where the authors performed the analyzes of all articles with the risk of bias domains. The methodology was defined following the PRISMA guidelines (Preferred Systematic Reviews and MetaAnalysis Report). The search retrieved 135 possibly relevant articles. After removing duplicates, according to the eligibility criteria, evaluation of titles and review of abstracts, in the end, 6 articles were included. An increase in anti-inflammatory cytokines, a decrease in pro-inflammatory cytokines and an increase in NO can be observed. The wavelengths used ranged from 660 to 808 nm when using a low intensity laser and when using a VIP light source 480-3400 nm, they also differed in terms of the light emission pattern. ILIB may be a complementary treatment option for patients who have comorbidities that lead to systemic inflammation.

The effect of photobiomodulation therapy in common maxillofacial injuries: Current status

The use of photobiomodulation therapy (PBMT) may be used for treating trauma to the maxillofacial region. The effects of PBMT on maxillofacial injuries were discussed in this review article. The electronic databases Pubmed, Scopus, and Web of Science were thoroughly searched. This review included in vitro, in vivo, and clinical studies describing how PBMT can be used in maxillofacial tissue engineering and regenerative medicine. Some studies suggest that PBMT may offer a promising therapy for traumatic maxillofacial injuries because it can stimulate the differentiation and proliferation of various cells, including dental pulp cells and mesenchymal stem cells, enhancing bone regeneration and osseointegration. PBMT reduces pain and swelling after oral surgery and tooth extraction in human and animal models of maxillofacial injuries. Patients with temporomandibular disorders also benefit from PBMT in terms of reduced inflammation and symptoms. PBMT still has some limitations, such as the need for standardizing parameters. PBMT must also be evaluated further in randomized controlled trials in various maxillofacial injuries. As a result, PBMT offers a safe and noninvasive treatment option for patients suffering from traumatic maxillofacial injuries. PBMT still requires further research to establish its efficacy in clinical practice and determine the optimal parameters.

Pulsed Red and Blue Photobiomodulation for the Treatment of Thigh Contusions and Soft Tissue Injury: A Randomized Controlled Trial

CONTEXT

Contusion and soft tissue injuries are common in sports. Photobiomodultion, light and laser therapy, is an effective aid to increase healing rates and improve function after various injury mechanisms. However, it is unclear how well photobiomodulation improves function after a contusion soft tissue injury. This study aimed to determine the effects of a pulsed red and blue photobiomodulation light patch on muscle function following a human thigh contusion injury.

DESIGN

Single-blinded randomized control trial design.

METHODS

We enrolled 46 healthy participants. Participants completed 5 visits on consecutive days. On the first visit, participants completed a baseline isokinetic quadriceps strength testing protocol at 60°/s and 180°/s. On the second visit, participants were struck in the rectus femoris of the anterior thigh with a tennis ball from a serving machine. Immediately following, participants were treated for 30 minutes with an active or placebo photobiomodulation patch (CareWear light patch system, CareWear Corp). Following the treatment, participants completed the same isokinetic quadriceps strength testing protocol. Participants completed the treatment and isokinetic quadriceps strength test during the following daily visits. We normalized the data by calculating the percent change from baseline. We used a mixed model analysis of covariance, with sex as a covariate, to determine the difference between treatment groups throughout the acute recovery process.

RESULTS

We found the active photobiomodulation treatment significantly increased over the placebo group, quadriceps peak torque during the 180°/s test (P = .030), and average power during both the 60°/s (P = .041) and 180°/s (P ≤ .001) assessments. The mean peak torque and average power of 180°/s, at day 4, exceeded the baseline levels by 8.9% and 16.8%, respectively.

CONCLUSIONS

The red and blue photobiomodulation light patch improved muscle strength and power during the acute healing phase of a human thigh contusion injury model.

Effect of high-intensity laser therapy versus shockwave therapy on selected outcome measures in osteoporotic long-term hemiparetic patients: a randomized control trial

BACKGROUND

This study aimed to compare the effects of high-intensity laser therapy (HILT) and extracorporeal shock wave therapy (ESWT) in treating consequences of osteoporosis in hemiparetic patients.

METHODS

A randomized controlled trial was conducted on hemiplegic patients with osteoporosis. They were randomly classified into three equal groups (n = 40 in each group). The control group received medication and traditional physiotherapy programs for stroke patients. The high-intensity laser (HIL) group received the same intervention as the control group in addition to high-intensity laser therapy. The shock wave (SW) group received the same intervention as the control group in addition to shock wave therapy. The three groups received an intervention that lasted 3 sessions/week for 12 weeks). All groups were assessed before and after therapy for the degree of pain, fall risk, and quality of life.

RESULTS

A statistically significant difference (p < 0.05) was found concerning VAS, which had a significant difference in favor of HILT and ESWT groups compared to the control group; however, no significant difference was determined between HIL and SW groups. Regarding the overall stability index, SFBBS, and QUALEFFO-41, there was a significant difference in favor of HIL and SW groups compared to the control group, and a significant difference was found in HIL when compared to SW.

CONCLUSION

The current study indicates that the combined traditional physical therapy and HILT and ESWT have clinical significance in improving osteoporotic long-term hemiparetic patients with more favor to HILT.

TRIAL REGISTRATION

The study was registered as a clinical trial at ClinicalTrial.gov ID (NCT05616611).

Whole-body photobiomodulation improves post-exercise recovery but does not affect performance or physiological response during maximal anaerobic cycling

This study aims to examine the effects of acute whole-body photobiomodulation (wbPBM), applied pre-exercise, on bouts of anaerobic cycling (Wingate) performances. Forty-eight healthy, active males and females participated in this single-blind, randomized, crossover study. Participants visited the laboratory three times to complete repeat (4 ×) Wingate testing, with one week between each visit. All participants completed baseline testing during their first visit and randomly received either the wbPBM or placebo condition before testing on the second visit, followed by the opposite condition on the third visit. There were no significant condition × time interactions for any variable (peak power, average power, power decrement, lactate, heart rate, ratings of perceived exertion, heart rate variability (HRV), root-mean square of differences between R-R intervals (rMSSD), power in the high-frequency range (HF) average, power in the low-frequency range (LF) average, total power, LF/HF, or power in the very-low-frequency range average). A main condition effect was only noted for heart rate, where peak heart rate was significantly higher for wbPBM (145, 141-148 bpm) than placebo (143, 139-146 bpm; p = 0.006) and baseline testing (143, 140-146; p = 0.049) throughout the entire testing session (i.e., collapsed across all timepoints). Furthermore, HRV (rMSSD) the following morning after testing was significantly higher for the wbPBM session compared to placebo (p = 0.043). There were no differences in perceived recovery (p = 0.713) or stress (p = 0.978) scores between wbPBM and placebo. Implementing 20 min of wbPBM immediately prior to maximal bouts of anaerobic cycling did not improve performance (i.e., power output) or physiological responses (e.g., lactate). However, wbPBM elicited the ability to work at a higher heart rate throughout testing and seemed to enhance recovery through improved HRV the following morning.

DOES PHOTOBIOMODULATION IMPROVE MUSCLE PERFORMANCE AND RECOVERY? A SYSTEMATIC REVIEW

ABSTRACT Photobiomodulation (PBM) appears to limit exercise-induced muscle damage, improve biochemical and functional recovery, and reduce inflammation and oxidative stress. This systematic review aimed to evaluate the effectiveness of photobiomodulation (PBM) in skeletal muscle recovery after exercise, addressing the different types of lasers and parameters used. Randomized clinical trials (RCTs) comparing the effects of PBM were included. The primary outcome evaluated was performance, and the secondary was inflammatory marker expression. The searches were conducted in March 2021. Fifteen RCTs that met the inclusion criteria were included. There was significant variability regarding the doses and wavelengths used, as well as in the types of lasers. However, in most studies, PBM promoted improvement of maximum voluntary contraction, better oxygen consumption, increased time to achieve exhaustion and fatigue, and decreased creatine kinase (CK), oxidative stress, and fatigue markers, mainly when used before exercise. Photobiomodulation applied before exercise, regardless of variations in doses and wavelengths, improves muscle performance and decreases levels of inflammation and fatigue markers. Evidence level II; Systematic review of level II studies.

Effects of Photobiomodulation and Low-Intensity Stretching on Delayed-Onset Muscle Soreness: A Randomized Control Trial

Objective: This study aimed to investigate the effects of photobiomodulation (PBM), low-intensity stretching, and their combination on delayed-onset muscle soreness (DOMS) in the untrained population. The relationships between DOMS and muscle function and functional performance were also tested. Methods: Fifty-four participants were randomized into four groups. Eccentric exercise was used to induce DOMS. Each group received either no treatment, PBM, stretching or PBM combined with stretching at 24, 48, and 72 h postexercise. Pressure pain threshold (PPT), numerical rating scale (NRS), single-leg forward jump (SLFJ), and maximum isometric voluntary contraction (MIVC) were measured at baseline, 24, 48, 72, and 96 h after eccentric exercise. Between-group differences were tested using two-way repeated measures analysis of variance and the relationships between DOMS and MIVC, and SLFJ were examined using Pearson's correlation analysis. Results: The PPT at the vastus medialis and vastus lateral in the PBM combined with stretching group was significantly lower than that in control group at 72 h (p = 0.045) and 48 h (p = 0.037) postexercise. No significant between-group difference in PPT was found for the rest occasions. There was no significant between-group difference in NRS, MVIC, and SLFJ on any occasion (p ≥ 0.052). DOMS was not correlated with MIVC and SLFJ (p ≥ 0.09). Conclusions: PBM or low-intensity stretching did not affect DOMS and functional performance in untrained individuals. The combination of PBM and low-intensity stretching increased pain sensitivity and did not relieve soreness. The DOMS was not associated with either muscle function or functional performance.

Can Photobiomodulation Therapy (PBMT) Minimize Exercise-Induced Oxidative Stress? A Systematic Review and Meta-Analysis

Oxidative stress induced by exercise has been a research field in constant growth, due to its relationship with the processes of fatigue, decreased production of muscle strength, and its ability to cause damage to the cell. In this context, photobiomodulation therapy (PBMT) has emerged as a resource capable of improving performance, while reducing muscle fatigue and muscle damage. To analyze the effects of PBMT about exercise-induced oxidative stress and compare with placebo therapy. Data Sources: Databases such as PubMed, EMBASE, CINAHL, CENTRAL, PeDro, and Virtual Health Library, which include Lilacs, Medline, and SciELO, were searched to find published studies. Study Selection: There was no year or language restriction; randomized clinical trials with healthy subjects that compared the application (before or after exercise) of PBMT to placebo therapy were included. Study Design: Systematic review with meta-analysis. Level of Evidence: 1. Data Extraction: Data on the characteristics of the volunteers, study design, intervention parameters, exercise protocol and oxidative stress biomarkers were extracted. The risk of bias and the certainty of the evidence were assessed using the PEDro scale and the GRADE system, respectively. Results: Eight studies (n = 140 participants) were eligible for this review, with moderate to excellent methodological quality. In particular, PBMT was able to reduce damage to lipids post exercise (SMD = −0.72, CI 95% −1.42 to −0.02, I2 = 77%, p = 0.04) and proteins (SMD = −0.41, CI 95% −0.65 to −0.16, I2 = 0%, p = 0.001) until 72 h and 96 h, respectively. In addition, it increased the activity of SOD enzymes (SMD = 0.54, CI 95% 0.07 to 1.02, I2 = 42%, p = 0.02) post exercise, 48 and 96 h after irradiation. However, PBMT did not increase CAT activity (MD = 0.18 CI 95% −0.56 to 0.91, I2 = 79%, p = 0.64) post exercise. We did not find any difference in TAC or GPx biomarkers. Conclusion: Low to moderate certainty evidence shows that PBMT is a resource that can reduce oxidative damage and increase enzymatic antioxidant activity post exercise. We found evidence to support that one session of PBMT can modulate the redox metabolism.

The Influence of Phototherapy on Recovery From Exercise-Induced Muscle Damage

Background

Intense physical activity can result in exercise-induced muscle damage, delayed-onset muscle soreness, and decrements in performance. Phototherapy (PhT), sometimes referred to as photobiomodulation or low-level laser therapy, may enhance recovery from vigorous exercise.

Purpose

The purpose of this study was to assess the influence of phototherapy on functional movements (vertical jump, agility), and perceptions of muscle soreness following exercise-induced muscle damage caused by high volume sprinting and decelerations.

Methods

In a between-group design, 33 participants performed 40x15m sprints, a protocol intended to cause muscle damage. Immediately following sprinting and in the four days following, vertical jump and agility were assessed, as well as calf, hamstring, quadriceps, and overall perceptions of soreness. Sixteen subjects (age 20.6±1.6 yrs; BMI 25.8±4.6 kg.m-2) received PhT prior to testing each day, while 17 (age 20.8±1.3 yrs; BMI 26.2±4.5 kg.m-2) received sham PhT and served as a control (CON). Measurements were recorded during five days of recovery from the repeated sprint protocol, then compared to those recorded during three baseline days of familiarization. Area under the curve was calculated by summing all five scores, and comparing those values by condition via a two-tailed unpaired t-test for normally distributed data, and a two-tailed Mann-Whitney U test for nonparametric data (alpha level = 0.05).

Results

Calf soreness was lower in PhT compared to CON (p = 0.02), but no other significant differences were observed between groups for vertical jump, agility, quadriceps, hamstring, and overall soreness (p > 0.05).

Discussion

Phototherapy may attenuate soreness in some muscle groups following exercise-induced muscle damage, but may not enhance recovery after explosive, short-duration activities.

Conclusion

Phototherapy may not be a useful recovery tool for those participating in explosive, short-duration activities.

Level of evidence

2c.

Analysis of pain relief and functional recovery in patients with rotator cuff tendinopathy through therapeutic ultrasound and photobiomodulation therapy: a comparative study

This study aimed to compare shoulder tendinopathy treatment with therapeutic ultrasound combined with LED photobiomodulation therapy using LED-infrared (850 nm) or LED-red (640 nm). The study assessed 75 patients, aged 45 to 70 years, distributed into five experimental groups (15 patients each): therapeutic ultrasound (US), infrared light irradiation (IR), visible red light irradiation (VR), infrared light and ultrasound combined (IR-US), and red light in conjunction with ultrasound (VR-US). The ultrasound parameters are 1 MHz, 0.5 W/cm² (SATA), and 100 Hz repetition rate, applied for 4 min each session. LED irradiation protocols were as follows: 3 points, 7.5 J per point, IR-LED 750 mW, 10 s, VR-LED 250 mW, 30 s. LED irradiation is followed by ultrasound in the combined therapies. The efficiency of the five therapies was evaluated assessing 12 parameters: quality of life (Health Assessment Questionnaire, HAQ), pain intensity (Visual Analog Scale, VAS), articular amplitude of shoulder movement (flexion, extension, abduction, adduction, medial rotation, lateral rotation), muscle strength (abduction, lateral rotation), and electromyography (lateral rotation, abduction). Treatments comprised 12 sessions for 4 weeks. Intra-group analysis showed that the five therapies significantly improved the recovery of all parameters after treatment. Regarding the comparison of irradiated therapies and ultrasound, statistical analysis showed that IR-US was a better treatment than US for all 12 parameters. IR treatment exceeded US on 9 items, whereas that VR and VR-US therapies exceeded US in 7 and 10 parameters, respectively (p < 0.05). Because of that, IR-US shows to be the best treatment for rotator cuff tendinopathy. In conclusion, improvements in quality of life, pain intensity relief, shoulder amplitude motion, and muscle strength force obtained with ultrasound therapy are enhanced by adding infrared LED irradiation to ultrasound for patients suffering from rotator cuff tendinopathy. This study was registered with the Brazilian Registry of Clinical Trials (ReBEC) under Universal Trial Number (UTN) U1111-1219-3594 (2018/22/08).

Effects of photobiomodulation and deep water running in patients with chronic non-specific low back pain: a randomized controlled trial

Photobiomodulation therapy (PBM) is often used to treat musculoskeletal disorders such as chronic non-specific low back pain (NSCLBP) as it can have positive effects on biomarkers-creatine kinase (CK) and serum cortisol levels-related to stress caused by physical exercise, such as deep water running (DWR) or by pain. The aim of this study was to evaluate the effects of the combination of PBM and aquatic exercise (DWR) on the intensity of pain, disability, 6-min walk test adapted (6WTA), and on cortisol and creatine kinase (CK) levels in a population with NSCLBP. The participants were allocated into three groups: TG_PBM (Photobiomodulation and Training Group), TG_PLA (Placebo Photobiomodulation and Training Group), and the G_PBM (Photobiomodulation Group). Information regarding anthropometric data, blood pressure, and heart rate were collected, and the questionnaires were applied: IPAQ-Short Form, Oswestry Disability Index, and the Visual Analog Scale for Pain. The submaximal exercise test (6WTA) was performed. Blood was collected for analysis of cortisol and CK levels. The training sessions were performed twice a week, for 4 weeks. In the intragroup comparisons, there were statistically significant changes in the TG_PBM and G_PBM groups in the outcomes pain intensity, disability (reductions in both groups), and in cortisol (increased in the TG_PBM and reduced in the G_PBM); in the TG_PLA group, there was a statistically significant reduction only in the outcome of pain intensity. In the intergroup comparison, in the comparison between TG_PBM and TG_PLA, there was a statistically significant difference in the level of cortisol, as well as in the comparison between TG_PBM and G_PBM, in which there was a statistically significant difference for this same outcome (cortisol) and for the 6WTA outcome. The effects of the combination of PBM and aquatic exercise have positive effects on reducing pain intensity, disability, and cortisol levels, but its effects on other variables (6WTA and CK) are too small to be considered significant. Trial registration number: NCT03465228-April 3, 2019; retrospectively registered (ClinicalTrials.gov).

Photobiomodulation and Sports: Results of a Narrative Review

Benefits of photobiomodulation (PBM) have been known for several decades. More recently, PBM applied in sports offers a special chance to support the modeling of the performance and recovery. Increasingly complex physical activities and fierce competition in the world of sports generate a state of psycho-emotional and physical stress that can induce chronic fatigue syndrome, failure in physical training, predisposition to muscle damage, physical and emotional exhaustion etc., for which PBM could be an excellent solution. To evaluate and identify all risk factors and the influence of PBM on health and performance in sport and for a better understanding of its effects, we did a search for "Photobiomodulation and Sports" on PubMed, to update the PBM science applied in sports, and we retained for analysis the articles published from 2014 to date. The term "PBM" is recent, and we did not include previous studies with "low level laser therapy" or "LLLT" before 2014. In the present research, PBM has been shown to have valuable protective and ergogenic effects in 25 human studies, being the key to success for high performance and recovery, facts supported also by 22 animal studies. PBM applied creatively and targeted depending on sport and size of the level of physical effort could perfectly modulate the mitochondrial activity and thus lead to remarkable improvements in performance. PBM with no conclusive results or without effects from this review (14 studies from a total of 39 on humans) was analyzed and we found the motivations of the authors from the perspective of multiple causes related to technological limitations, participants, the protocols for physical activity, the devices, techniques and PBM parameters. In the near future, dose-response experiments on physical activity should be designed and correlated with PBM dose-response studies, so that quantification of PBM parameters to allow the energy, metabolic, immune, and neuro-endocrine modulation, perfectly coupled with the level of training. There is an urgent need to continuously improve PBM devices, delivery methods, and protocols in new ingenious future sports trials. Latest innovations and nanotechnologies applied to perform intracellular signaling analysis, while examining extracellular targets, coupled with 3D and 4D sports motion analysis and other high-tech devices, can be a challenge to learn how to maximize PBM efficiency while achieving unprecedented sports performance and thus fulfilling the dream of millions of elite athletes.

Using a single dose of photobiomodulation (laser + LED) to improve performance of lower limbs in functional test: Randomized clinical trial

BACKGROUND

Photobiomodulation (PBM) improves motor performance despite doubts whether it occurs immediately or late after a single dose. We evaluated the effect of a cluster PMB (laser + LED) single dose on muscle fatigue recovery in young sedentary adults, both immediately and in the short term (period between 24 and 48 h) after the fatiguing event.

METHODS

Randomized clinical trial with 60 volunteers randomized in 5 groups (n = 12 in each): control/(CG); placebo/(SG); PBM in knee extensor/(KE_G); plantar-flexor/(PF_G); knee extensor + plantar-flexor/(KE + FP_G). Before the intervention (pre) a fatiguing event (FE) was applied, which consisted in going up and down one step until exhaustion. Repetition number (RN) and time to exhaustion (TTE) were recorded. Then each group received its respective intervention and immediately after that, the FE was performed again (immediate post). In the period between 24 and 48 h after irradiation, a new FE was performed (late post). In addition to the comparative statistics, complementary metrics (if the mean difference [Diff] between the comparison pairs was higher or lower than minimum detectable change [MDC] and effect size [ES]) were calculated.

RESULTS

Through the integrated analysis of inferential statistics and complementary metrics, it was observed that although there was no time of evaluation effect, there was a group effect. PBM improved performance in KE + FP_G (p-value<0.05; Diff>MDC; ES = moderate) and PF_G (p-value>0.05; but Diff > MDC; ES = moderate) regarding CG for both RN and TTE.

CONCLUSION

A PBM single dose irradiation may improve motor performance and there is specificity of the irradiated muscle group, although it does not depend on the moment.

Effects of Low-Level Laser Therapy on Muscular Performance and Soreness Recovery in Athletes: A Meta-analysis of Randomized Controlled Trials

CONTEXT

Athletes must maintain their peak state of strength. Previous studies have investigated the effect of low-level laser therapy (LLLT) on muscular performance. A previous systematic review and meta-analysis has investigated this issue in healthy participants but not in physically active athletes.

OBJECTIVE

To investigate whether LLLT can improve muscular performance and soreness recovery in athletes.

DATA SOURCES

PubMed, EMBASE, and Cochrane Library.

STUDY SELECTION

Published randomized controlled trials and crossover studies till December 2020.

STUDY DESIGN

Systematic review and meta-analysis.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Assessment of study quality was rated using the risk of bias assessment method for randomized trials (Cochrane Handbook for Systematic Reviews of Interventions).

RESULTS

A total of 24 studies were included. LLLT application before exercise significantly improved lower-limb muscle strength in 24-hour, 48-hour, 96-hour, and 8-week follow-up groups. Furthermore, decreased soreness index, serum creatine kinase concentrations, interleukin-6, and thiobarbituric acid reactive substance concentrations and a trend toward the improvement of contract repetition number and VO₂ kinetic outcomes were observed.

CONCLUSION

Although a definite therapeutic effect of LLLT is yet to be established, the current evidence supports that LLLT use improves muscular performance in physically active athletes. Additional trials with large sample sizes and robust design should be conducted before strong recommendations are made.

Photobiomodulation Before Eccentric Fatigue Protocol in the Control of Pain and Muscle Damage Markers: A Double-Blind, Randomized Controlled Study

Background: Several strategies are used in the management of delayed-onset muscle soreness (DOMS), but there is not always evidence to justify its use. Photobiomodulation (PBM) is a noninvasive means, with promising previous results of its use in this outcome. Objective: This study aimed to identify the effects of PBM in the femoral quadriceps region to reduce DOMS in men undergoing a fatigue protocol. Methods: This is a double-blind, randomized controlled study. The sample consisted of 35 physically active men. The volunteers were divided into two groups: pre-fatigue PBM [Group 1 (G1)] and post-fatigue PMB [Group 2 (G2)]. The fatigue test was conducted at the same time of day. Given this was a crossover study of volunteers, we used at least a 1-week washout to avoid any residual interference from the previous intervention. PBM (active/placebo) was performed 5 min before the start of the fatigue protocol in G1 and immediately after the fatigue protocol in G2. PBM was applied at six points on the femoral quadriceps muscle (cluster laser/light emitting diodes 13, 415 mW, 30.2 J per point, 73 sec per application, and total dose of 181.2 J). In the data analysis, the primary endpoint was DOMS measured using a Numerical Pain Scale, and the secondary outcome was examined on the effects of PMB muscle damage, muscle contraction, and isometric horizontal jump. Results: There were significant differences to PBM compared with the placebo group for DOMS, with no differences between the times of application. For muscle damage, there was significant difference (p > 0.05) when PBM was applied in pre-fatigue. G1 led to an increase of 14.9% in the creatine kinase level when active since the application of placebo PBM increased by 65% (p = 0.04). Conclusions: The PBM applied before eccentric fatigue protocol showed no significant results on DOMS, although there was a positive effect to control muscle damage. Brazilian Registry of Clinical Trials (RBR-7qhddz).

Full Body Photobiomodulation Therapy to Induce Faster Muscle Recovery in Water Polo Athletes: Preliminary Results

Objective: To investigate the recovery of male water polo athletes applying full body photobiomodulation therapy (PBMT) regarding inflammation and muscle damage markers, testosterone and cortisol hormonal responses, heart rate variability (HRV), maximal voluntary contraction, and squat jump (SJ) after official water polo matches. Background: PBMT has been applied locally on specific muscle groups to induce faster recovery and improve the performance of athletes and nonathletes. However, many sports modalities require movement of the whole body, and a full body PBMT could be more adequate to irradiate large muscle areas homogeneously and faster. Methods: In a randomized, parallel, and double-blinded design, 13 athletes (whole team) aged 18 years attended the study and were allocated into two groups: PBMT (dose of 6.9 J/cm², irradiance of 46.17 mW/cm², 5 min irradiation) and placebo treatment. The study was conducted during the 2019 Brazilian under 20 water polo championship. All athletes were assessed by blood samples and neuromuscular evaluation. Immediately after each match, all athletes received PBMT (effective or placebo). Results: No significant interactions (raw values and percentage related to baseline) were observed for testosterone and cortisol, tumor necrosis factor-alpha, interleukin-6, creatine kinase concentration, maximal isometric voluntary contraction, SJ test, and HRV. Only an isolated interaction (decrease) was found for lactate dehydrogenase (LDH) response after the first match (p = 0.004, post-hoc p = 0.038). Conclusions: The parameters of the full body PBMT of this study did not induce faster recovery of inflammatory, muscle damage (excepting LDH), testosterone, cortisol, HRV, and neuromuscular responses during repeated days of water polo matches.

Does Low-Level Laser Therapy Decrease Muscle-Damaging Mediators After Performance in Soccer Athletes Versus Sham Laser Treatment? A Critically Appraised Topic

Clinical Scenario: Low-level laser therapy (LLLT) is a controversial topic for its use in athletic recovery, mainly due to inconsistency in research regarding the application of LLLT. Articles on LLLT have assessed its effectiveness in untrained humans through pain scales, functional scales, and blood draws, and it has been found capable in nonathletic rehabilitative use. The controversy lies with LLLT in the recovering athlete. Not only do athletes need to perform at high levels, but each sport is unique in the metabolic demands placed on the athletes' bodies. This modality can alter chemical mediators of the inflammatory process, specifically blood lactate (BL) and creatine kinase (CK). During soccer contests, it is a common problem for athletes to have an average CK level of 800 U/L and BL of 8 mmol·L, increasing delayed-onset muscle soreness and fatigue. Micro-CK level elevation is associated with cellular membrane damage, localized hypoxia, and electrolyte imbalances, hindering the recovery process. Clinical Question: Does LLLT decrease muscle-damaging mediators effecting player fatigue and delayed-onset muscle soreness after performance in soccer athletes versus sham treatment? Summary of Key Findings: In 3 studies, preperformance, postperformance, or preperformance and postperformance LLLT was performed and evaluated BL (2 of 3) and CK (2 of 3). In each article, BL and CK showed a significant decrease (P < .05) when performed either preperformance or postperformance versus the control group. The greatest decrease in these mediators was noticed when postperformance laser therapy was performed. Clinical Bottom Line: LLLT at 10, 30, or 50 J performed at a minimum of 2 locations on the rectus femoris, vastus lateralis, and vastus medialis bilaterally for 10 seconds each is significant in decreasing blood serum levels of BL and CK when performed postexercise. Strength of Recommendations: All 3 articles obtained a Physiotherapy Evidence Database score of ≥8/10.

What is the optimal time-response window for the use of photobiomodulation therapy combined with static magnetic field (PBMT-sMF) for the improvement of exercise performance and recovery, and for how long the effects last? A randomized, triple-blinded, placebo-controlled trial

Background

The optimal time-response window for photobiomodulation therapy (PBMT) using low-level laser therapy (LLLT) and/or light emitting diodes therapy (LEDT) combined with static magnetic fields (sMF) before physical activity still was not fully investigated. The aim of the present study was to investigate the better of four time-response windows for PBMT combined with sMF (PBMT-sMF) use before exercise in humans.

Methods

A prospectively registered, randomized, triple-blinded (volunteers, therapists and assessors) placebo-controlled trial was carried out. Sixty healthy untrained male subjects were randomly allocated to six experimental groups (n = 10 per group): PBMT-sMF 5 mins, PBMT-sMF 3 h, PBMT-sMF 6 h, PBMT-sMF 1-day, placebo, and control. The control group performed all procedures, however did not receive any kind of intervention. PBMT-sMF active or PBMT-sMF placebo was applied precisely in different time points after baseline MVC test to ensure that both MVC tests and eccentric exercise protocol would occur at the same hour of the day in all groups. Then, after five minutes, 3 h, 6 h or 1-day (24 h) of PBMT-sMF treatment (active or placebo) the eccentric exercise protocol was performed. The primary outcome was peak torque obtained from maximum voluntary contraction (MVC). The secondary outcomes were creatine kinase (CK), and delayed onset muscle soreness (DOMS). The primary and secondary outcomes were measured at baseline, immediately after, 1 h, 24 h and 48 h after the eccentric exercise protocol.

Results

Sixty patients were randomized and analyzed to each sequence. The outcomes in absolute values show that all active PBMT-sMF groups increased (p < 0.05) MVC from immediately after to 1 h after eccentric exercise, and decreased (p < 0.05) CK activity at all time points. However, PBMT-sMF 5 mins, 3 h and 6 h groups showed better results in MVC and CK analysis from 24 h to 48 h, and also to DOMS (p < 0.05) at all time points. Participants did not report any adverse events.

Conclusions

PBMT-sMF can be used from 5 min to 6 h before exercise, and the effects can last up to 54 h after treatment. However, the effects start to decrease when a 1-day (24 h) time-response window is used.

Trial registration

NCT03420391. Registered 05 February 2018.

Does Previous Application of Photobiomodulation Using Light-Emitting Diodes at Different Energy Doses Modify the Peak Running Velocity and Physiological Parameters? A Randomized, Crossover, Double-Blind, and Placebo-Controlled Study

Objective: This study aimed to verify the acute effects of photobiomodulation (PBM) using different doses of LED on peak running velocity (V_peak) and physiological parameters. Materials and methods: The study had a randomized, crossover, double-blind, and placebo-controlled format, in which 15 physically active males were submitted, besides the control (CON), to four conditions performed 5 min before the maximal incremental treadmill tests for the determination of V_peak: placebo (PLA) and three conditions of PBM application at different doses: PBM applied with 30 J per area (PBM₁), PBM applied with 120 J per area (PBM₂), and PBM applied with 180 J per area (PBM₃). The LED was applied using an equipment with 56 diodes of red light (660 nm; 50 mW/cm² and 1.5 J/cm² each diode) and 48 diodes of infrared light (850 nm; 150 mW/cm² and 4.5 J/cm² each diode). The PBM was applied in two regions of the quadriceps muscle, two regions of the femoral biceps muscle, and one region of the gastrocnemius muscle in both legs. Results: There was no difference among the outcomes from PBM irradiations and PLA condition for the variables, V_peak (CON = 13.4 ± 1.6; PLA = 13.4 ± 1.6; PBM₁ = 13.5 ± 1.7; PBM₂ = 13.4 ± 1.6; PBM₃ = 13.4 ± 1.7 km/h), similar to other variables associated with aerobic running performance analyzed during the maximal incremental treadmill tests for V_peak determination: lactate peak, heart rate, and rating of perceived exertion. Conclusions: We concluded that the application of different doses of PBM using LEDs did not modify V_peak and physiological and perceptual parameters.

Does Photobiomodulation Therapy Enhance Maximal Muscle Strength and Muscle Recovery?

Photobiomodulation has been shown to improve tissue and cell functions. We evaluated the influence of photobiomodulation, using a B-Cure laser, on: 1) maximal performance, and 2) muscle recovery after resistance exercise. Two separate crossover randomized double-blinded placebo-controlled trials were conducted. Sixty healthy physical education students (28 men, 32 women), aged 20-35, were recruited (30 participants for each trial). Participants performed two interventions for each experiment, with real lasers (GaAlAs, 808 nm) on three quadricep locations in parallel (overall treatment energy of ~150J) or sham (placebo) treatment. In the first experiment muscle total work (TW) and peak torque (PT) were measured by an isokinetic dynamometer in five repetitions of knee extension, and in the second experiment muscle recovery was measured after the induction of muscle fatigue by evaluating TW and PT in five repetitions of knee extension. There were no differences between treatments (real or sham) regarding the TW (F(1,28) = 1.09, p = .31), or PT (F(1,29) = .056, p = .814). In addition, there was no effect of photobiomodulation on muscle recovery as measured by the TW (F(1,27) = .16, p = .69) or PT (F(1,29) = .056, p = .814). Applying photobiomodulation for 10 min immediately before exercise did not improve muscle function or muscle recovery after fatigue.

Low-Level Laser Light Therapy Dosage Variables vs Treatment Efficacy of Neuromusculoskeletal Conditions: A Scoping Review

OBJECTIVE

The purpose of this scoping review was to identify and synthesize literature on dosage variables on the efficacy of low-level laser therapy (LLLT) for neuromusculoskeletal conditions.

METHODS

A scoping literature review was conducted by searching the following databases: the Cochrane Library, the Cumulative Index to Nursing and Allied Health Literature, Medline, the Physiotherapy Evidence Database, the Index to Chiropractic Literature, manufacturer websites, and online guidelines. The search was modeled after STARLITE criteria. The reporting used Preferred Reporting Items for Systematic Reviews and Meta-analyses Extension for Scoping Reviews (PRISMA-ScR). Articles were included if LLLT was used in any treatment group for a neuromusculoskeletal complaint with dosage and effectiveness reported. This was tabulated by source, dosage variables, conditions, outcome measures, and conclusions. Data were charted in Excel format. Frequency counts were performed on ordinal data. Descriptive statistics were computed for the continuous data.

RESULTS

A total of 86 articles were included in the review. They revealed a broad range of musculoskeletal conditions and diverse dosage parameters. Seven individual parameters were found that would alter the dosage. Although duration of application is an independent clinical factor, the negative-outcome studies were inconsistent in duration. There was lack of statistical difference between the studies with improved vs unimproved outcomes. No statistical differences were noted between the dosage parameters and efficacy.

CONCLUSION

Although many articles were found on LLLT for neuromusculoskeletal conditions, the studies had amorphous parameters. A heterogeneity of reported doses precluded the synthesis of sufficient evidence to correlate dosage variables with improved or unimproved outcomes. Therefore, based on the current literature, dosage variables for the efficacy of LLLT for neuromusculoskeletal conditions are uncertain at this time.

Phototherapy on Management of Creatine Kinase Activity in General Versus Localized Exercise: A Systematic Review and Meta-Analysis

OBJECTIVE

The main focus of this systematic review was to determine the efficacy of phototherapy in the management of creatine kinase (CK) activity after exercise and furthermore to identify for which exercise model protocol phototherapy provides the best results.

DESIGN

Meta-analysis comparing phototherapy with a control condition.

SETTING

The MEDLINE, EMBASE, SPORTDiscus, PEDro, and CENTRAL databases were searched from their earliest records to October 03, 2016. Data were pooled in a meta-analysis and described as standardized mean difference (SMD) with 95% confidence intervals (CIs) using a random effects model.

PARTICIPANTS

Healthy subjects (no restrictions were applied, eg, age, sex, and exercise level).

INTERVENTION

Phototherapy (low-level laser therapy and/or light-emitting diode therapy) before or after exercise and a placebo or control condition.

MAIN OUTCOME MEASURES

Creatine kinase activity (no restriction to any analysis, eg, serum, plasma, or capillary blood).

RESULTS

Fourteen studies were included for review. The results revealed that phototherapy has a more positive effect than control condition in management of CK activity [SMD = 0.77, 95% CI (0.32 to 1.22); P = 0.0007; I = 72%]. In exploratory analysis, the results showed that phototherapy was effective only in the exercise protocol with localized exercise with large effect size [localized exercise: SMD = 0.89, 95% CI (0.26 to 1.51); P = 0.0002; I = 76%; general exercise: SMD = 0.61, 95% CI (-0.05 to 1.26); P = 0.07; I = 67%].

CONCLUSIONS

The available evidence suggest that phototherapy has beneficial effects on the management of CK activity and demonstrate a possible relationship based on damage caused by exercise, providing a greater effect in studies that used localized exercise.

The Effects of Whole-Body Photobiomodulation Light-Bed Therapy on Creatine Kinase and Salivary Interleukin-6 in a Sample of Trained Males: A Randomized, Crossover Study

Photobiomodulation therapy (PBMT) can be applied to the whole body as compared to the application of using single hand-held devices that isolate a smaller muscle area. The purpose of this study was to examine the effects of an acute dose of whole-body PBMT pre- and post-high-intensity resistance training on creatine kinase (CK) and salivary interleukin-6 (IL-6) in a sample of trained males. Twelve males (31 ± 8.3 years, 177.2 ± 5.4 cm, and 86.0 ± 7.5 kg) were part of a randomized, counterbalanced, cross-over design, whereby each participant performed a high-intensity resistance training session that consisted of the bench press, chin-up, and repeated sprints on two separate occasions. Each participant was assigned to either the PBMT or control condition on two separate weeks, with a 10-days washout period between the weeks. Creatine kinase was measured at baseline, 24, 48, and 72 h post-exercise. Salivary IL-6 was measured at baseline, 60, 90, and 120 min. A paired t-test showed no significant difference (p = 0.669) in the area under the curve (AUC) for CK during the PBMT (191.7 ± 48.3) and control conditions (200.2 ± 68.0). A Wilcoxon signed-rank test also showed no significant median difference (p = 0.155) in the AUC for salivary IL-6 during the PBMT (Mdn = 347.7) and control conditions (Mdn = 305.8). An additional Wilcoxon signed-rank test for CK percentage change from 24 to 72 h showed the PBMT condition (Mdn = −45%) to have a −18% median difference as compared to the control condition (Mdn = −41%). As such, whole-body PBMT does not significantly reduce the activity of salivary IL-6 or CK concentration during the 24 to 72-h recovery post-high-intensity resistance training.

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

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

Does the combination of photobiomodulation therapy (PBMT) and static magnetic fields (sMF) potentiate the effects of aerobic endurance training and decrease the loss of performance during detraining? A randomised, triple-blinded, placebo-controlled trial

Background

Photobiomodulation (PBMT) is a therapy that uses non-ionising forms of light, including low-level lasers and light-emitting diodes (LEDs) that may be capable of modulating cellular activity. Some biological processes may also interact with static magnetic fields (sMF), leading to modulatory effects on cells. Previous studies have verified that the combination of PBMT and sMF (PBMT/sMF) enhances the performance of individuals during aerobic training programs. The detraining period can cause losses in aerobic capacity. However, there is no evidence of the existence of any recourse that can decrease the effects of detraining. We aimed to investigate the effects of PBMT/sMF application during training and detraining to assess the effectiveness of this treatment in reducing the effects of detraining.

Methods

Sixty male volunteers were randomly allocated into four groups— participants who received PBMT/sMF during the training and detraining (PBMT/sMF + PBMT/sMF); participants who received PBMT/sMF during the training and a placebo in the detraining (PBMT/sMF + Placebo); participants who received a placebo during the training and PBMT/sMF in the detraining (Placebo+PBMT/sMF); and participants who received a placebo during the training and detraining (Placebo+Placebo). Participants performed treadmill training over 12 weeks (3 sessions/week), followed by 4 weeks of detraining. PBMT/sMF was applied using a 12-diode emitter (four 905 nm super-pulsed lasers, four 875 nm light-emitting diodes (LEDs), four 640 nm LEDs, and a 35 mT magnetic field) at 17 sites on each lower limb (dosage: 30 J per site). The data were analysed by two-way repeated measures analysis of variance (ANOVA, time vs experimental group) with post-hoc Bonferroni correction.

Results

The percentage of change in time until exhaustion and in maximum oxygen consumption was higher in the PBMT/sMF + PBMT/sMF group than in the Placebo+Placebo group at all time-points (p < 0.05). Moreover, the percentage of decrease in body fat at the 16th week was higher in the PBMT/sMF + PBMT/sMF group than in the Placebo+Placebo group (p < 0.05).

Conclusions

PBMT/sMF can potentiate the effects of aerobic endurance training and decrease performance loss after a 4-week detraining period. Thus, it may prove to be an important tool for both amateur and high-performance athletes as well as people undergoing rehabilitation.

Trial registration

NCT03879226. Trial registered on 18 March 2019.

Applications of Photobiomodulation Therapy to Musculoskeletal Disorders and Osteoarthritis with Particular Relevance to Canada

Background: Musculoskeletal disorders caused by osteoarthritis (MSDs/OA) are a growing problem in the modern industrialized society in Canada. Overall aging of the general population and a progressive lack of exercise contribute to this alarming increase. Moreover, a range of chronic conditions including cardiovascular and mental diseases show significantly higher comorbidity with MSDs/OA. Conventional medical treatment for MSDs/OA includes nonsteroidal anti-inflammatory drugs and opiate pain killers. These drugs have major drawbacks such as a relative lack of efficacy, potential for addiction, and even death (Vioxx scandal). Photobiomodulation (PBM) was discovered over 50 years ago but has still not attained widespread acceptance by the medical community. This is partly due to uncertainty about the precise molecular mechanisms of action and a bewildering array of different wavelengths and dosimetric parameters employed in reported studies. Objective: The goal of this review was to survey literature reports of PBM, also known as low-level laser therapy used for treatment of MSDs/OA, concentrating on the growth over time, different wavelengths employed, and application to different joints. Methods: We searched the PubMed database for publication of study on PBM to treat the most common joints. Results: We show that the field of PBM to treat MSDs/OA is expanding exponentially over the past 20 years. A trend has emerged over time for more power to achieve better effective treatments, and the understanding of the physiological effect of safe parameters has improved. There is, however, no consensus on the best set of parameters to treat a specific patient indication. Conclusions: Finally, we highlight gaps in our knowledge and the barriers to further clinical trials. We suggest that the growing body of evidence indicating efficacy, and the almost total lack of side effects, should encourage continued clinical research to support clinical applications where better rehabilitation treatments are much needed.

Infrared Low-Level Laser Therapy (Photobiomodulation Therapy) before Intense Progressive Running Test of High-Level Soccer Players: Effects on Functional, Muscle Damage, Inflammatory, and Oxidative Stress Markers-A Randomized Controlled Trial

The effects of preexercise photobiomodulation therapy (PBMT) to enhance performance, accelerate recovery, and attenuate exercise-induced oxidative stress were still not fully investigated, especially in high-level athletes. The aim of this study was to evaluate the effects of PBMT (using infrared low-level laser therapy) applied before a progressive running test on functional aspects, muscle damage, and inflammatory and oxidative stress markers in high-level soccer players. A randomized, triple-blind, placebo-controlled crossover trial was performed. Twenty-two high-level male soccer players from the same team were recruited and treated with active PBMT and placebo. The order of interventions was randomized. Immediately after the application of active PBMT or placebo, the volunteers performed a standardized high-intensity progressive running test (ergospirometry test) until exhaustion. We analyzed rates of oxygen uptake (VO_{2 max}), time until exhaustion, and aerobic and anaerobic threshold during the intense progressive running test. Creatine kinase (CK) and lactate dehydrogenase (LDH) activities, levels of interleukin-1β (IL-1-β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α), levels of thiobarbituric acid (TBARS) and carbonylated proteins, and catalase (CAT) and superoxide dismutase (SOD) activities were measured before and five minutes after the end of the test. PBMT increased the VO_{2 max} (both relative and absolute values—p < 0.0467 and p < 0.0013, respectively), time until exhaustion (p < 0.0043), time (p < 0.0007) and volume (p < 0.0355) in which anaerobic threshold happened, and volume in which aerobic threshold happened (p < 0.0068). Moreover, PBMT decreased CK (p < 0.0001) and LDH (p < 0.0001) activities. Regarding the cytokines, PBMT decreased only IL-6 (p < 0.0001). Finally, PBMT decreased TBARS (p < 0.0001) and carbonylated protein levels (p < 0.01) and increased SOD (p < 0.0001)and CAT (p < 0.0001) activities. The findings of this study demonstrate that preexercise PBMT acts on different functional aspects and biochemical markers. Moreover, preexercise PBMT seems to play an important antioxidant effect, decreasing exercise-induced oxidative stress and consequently enhancing athletic performance and improving postexercise recovery. This trial is registered with Clinicaltrials.gov NCT03803956.

Effects of photobiomodulation therapy combined to static magnetic field in strength training and detraining in humans: protocol for a randomised placebo-controlled trial

INTRODUCTION

In recent years, it has been demonstrated that photobiomodulation therapy (PBMT) using low-level laser therapy and/or light-emitting diode therapy combined to static magnetic field (sMF) has ergogenic effects, improving muscular performance and accelerating postexercise recovery. However, many aspects related to these effects and its clinical applicability remain unknown. Therefore, the aim of this project is to evaluate the ergogenic effects of PBMT/sMF in detraining after a strength-training protocol.

METHODS AND ANALYSIS

The study will be a randomised, triple-blind, placebo-controlled clinical trial. Healthy male volunteers will be randomly distributed into four experimental groups: PBMT/sMF before training sessions + PBMT/sMF during detraining, PBMT/sMF before training sessions + placebo during detraining, placebo before training sessions + PBMT/sMF during detraining and placebo before training sessions + placebo during detraining. Strength-training sessions will be carried out over 12 weeks, and the detraining period will occur during the 4 weeks after. The muscular strength and the structural properties of quadriceps will be analysed.

ETHICS AND DISSEMINATION

This study was approved by the Research Ethics Committee of Nove de Julho University. The results from this study will be disseminated through scientific publications in international peer-reviewed journals and presented at national and international scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03858179.

Efficacy of laser therapy for exercise-induced fatigue: A meta-analysis

BACKGROUND

Laser therapy is widely used for exercise-induced fatigue, while the effect among different studies remains controversial. The present study was to summary available randomized controlled trials (RCTs) to evaluate the effect of laser therapy in subjects with exercise-induced fatigue.

METHODS

PubMed, Embase, and Cochrane Library were searched to identify the potential RCTs from inception to October 2017. The weighted mean difference (WMD) with 95% confidence intervals (CIs) was calculated using a random-effects model.

RESULTS

Twenty RCTs involving a total of 394 individuals were included in final analysis. No significant differences were observed between the laser therapy and control for the outcomes of lactate (WMD: -0.19; 95%CI: -0.52 to 0.13; P = .244), repetitions (WMD: 4.44; 95%CI: -1.43 to 10.32; P = .138), work load (WMD: 3.38; 95%CI: -1.15 to 7.91; P = .144), time taken to perform the exercise tests (WMD: 4.42; 95%CI: -2.33 to 11.17; P = .199), creatine kinase (WMD: -41.80; 95%CI: -168.78 to 85.17; P = .519), maximum voluntary contraction (WMD: 23.83; 95%CI: -7.41 to 55.07; P = .135), mean peak forces (WMD: 2.87; 95%CI: -1.01 to 6.76; P = = .147), and visual analog scale (VAS) (WMD: -1.91; 95%CI: -42.89 to 39.08; P = = .927). The results of sensitivity analysis suggested that laser therapy might play an important role on the levels of lactate (WMD: -0.30; 95%CI: -0.59 to -0.01; P = = .040), maximum voluntary contraction (WMD: 33.54; 95%CI: 1.95 to 65.12; P = = .037), and VAS (WMD: -21.00; 95%CI: -40.78 to -1.22; P = = .037). The results of subgroup analyses indicated no significant differences between the laser therapy and placebo for lactate and repetitions when stratified by study design, mean age, gender, and study quality.

CONCLUSIONS

The findings of this meta-analysis did not indicate any significant differences between the laser therapy and placebo.

Effects of photobiomodulation therapy in aerobic endurance training and detraining in humans: Protocol for a randomized placebo-controlled trial

INTRODUCTION

Over the last 10 years, it has been demonstrated that photobiomodulation therapy (PBMT), also known as phototherapy, using low-level laser therapy (LLLT) and/or light-emitting diode therapy (LEDT) has ergogenic effects, improving athletic performance and also accelerating post-exercise recovery. However, many aspects related to these effects and its clinical applicability remain unknown. Therefore, the aim of this project is to evaluate the ergogenic effects of PBMT in detraining after an aerobic endurance training protocol.

METHODS AND ANALYZES

A randomized, triple-blind, placebo-controlled clinical trial will be carried out. Healthy male volunteers will be randomly distributed into 4 experimental groups: PBMT before and after training sessions + PBMT during detraining, PBMT before and after training sessions + placebo during detraining, placebo before and after training sessions + PBMT during detraining, and placebo before and after training sessions + placebo during detraining. The aerobic endurance training sessions will be carried out using motorized treadmills during 12 weeks, and the detraining period will consist in the next 4 weeks after that. It will be analyzed the time until exhaustion, maximal oxygen uptake (VO2max), and fat percentage of volunteers.

DISCUSSION

Despite the increasing body of evidence for the use of PBMT as an ergogenic agent, several aspects remain unknown. The findings of this study will contribute to the advance of knowledge in this field regarding clinical applications.

ETHICS AND DISSEMINATION

This study was approved by the Research Ethics Committee of Nove de Julho University. The results from this study will be further disseminated through scientific publications in international peer-reviewed journals and presentations at national and international scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03879226.

Effects of photobiomodulation therapy on inflammatory mediators in patients with chronic non-specific low back pain: Protocol for a randomized placebo-controlled trial

INTRODUCTION

Low back pain (LBP) is ranked as one of the most prevalent health conditions. It is likely that some inflammatory mediators could be associated with pain and disability in these patients. Photobiomodulation therapy (PBMT) is a non-pharmacological therapy often used in patients with LBP and one of the possible mechanisms of action of therapy is modulate inflammatory mediators. However, to date there are no studies that evaluated the effects of PBMT on the levels of inflammatory mediators in patients with LBP. The aim of this study is to evaluate the acute effects of PBMT on systemic levels of inflammatory mediators and pain intensity in patients with chronic non-specific low back pain.

METHODS AND ANALYSIS

This is a prospectively registered, two-arm randomized placebo-controlled trial with blinded patients, assessors and therapists. Eighteen patients with chronic non-specific LBP will be randomized into 2 groups: placebo or active PBMT. The treatment will be provided in a single session. The primary outcome will be levels of prostaglandin E2 (PGE2). The secondary outcomes will be levels of necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and pain intensity. Biochemical and clinical outcomes will be measured at baseline and 15 minutes after the single treatment session.

DISCUSSION

Despite PBMT be used in musculoskeletal disorders such as LBP, to the best of our knowledge this is the first study that will investigate a possible biological mechanism behind the positive clinical effects of PBMT on non-specific chronic low back pain.

ETHICS AND DISSEMINATION

The study was approved by the Regional Research Ethics Committee. The results will be disseminated through publication in peer-reviewed international journal and conferences.

TRIAL REGISTRATION NUMBER

NCT03859505.

Photobiomodulation by Led Does Not Alter Muscle Recovery Indicators and Presents Similar Outcomes to Cold-Water Immersion and Active Recovery

Purpose: The aim of the present study was to investigate the effectiveness of photobiomodulation therapy (PBMT) on muscle recovery based on inflammation (interleukin-10 [IL-10]; tumor necrosis factor-α [TNFα]), muscle damage markers (creatine kinase [CK]; lactate dehydrogenase [LDH]), delay onset muscle soreness (DOMS), and countermovement jump performance (CMJ) after two sprint interval training (SIT) sessions compared with a placebo condition (part-I), as well as to compare the effectiveness of PBMT with active recovery (AR) and cold-water immersion (CWI) (part-II). Methods: Part-I was conducted as a double-blind, randomized and placebo-controlled study and part-II as a parallel-group study. Thirty-six men participated in the studies (12 participants in part-I and 36 participants in part-II). Volunteers performed two SITs interspaced by 24-h (SIT₁ and SIT₂) to mimic the effect of accumulating 2 consecutive days of SIT. In part-I, only after SIT₂, PBMT [Total energy: 600J (300J per leg in 5 spots); wavelength: 660-850 nm] or placebo interventions were performed, while in part-II PBMT (part-I data), AR (15-min; 50% of the maximal aerobic power), or CWI (10-min; 10°C) were carried out, also after SIT₂. Blood samples were collected before (i.e., baseline), and 0.5, 1, 24, 48, and 72-h after SIT₂, while CMJ and DOMS were measured before, 24, 48, and 72-h after SIT₂. Results: In part-I, there were no interactions between PBMT and placebo conditions for any blood markers (P ≥ 0.313), DOMS (P = 0.052), and CMJ (P = 0.295). However, an effect of time was found with increases in LDH, CK, and IL-10 (P ≤ 0.043) as well as a decrease in DOMS at 72-h compared with 24-h (P = 0.012). In part-II, there were no interactions between the PBMT, AR, and CWI groups for any markers at the same moments (P ≥ 0.189) and for the peak and integral values (P ≥ 0.193), for DOMS (P = 0.314) and CMJ (P = 0.264). However, an effect of time was found with an increase in CK and IL-10 (P = 0.003), while DOMS decreased at 48 and 72-h compared with 24-h (P = 0.001). Conclusion: In summary, PBMT had no effect on inflammation, muscle damage, CMJ performance, or DOMS after two consecutive sprint interval training sessions compared to placebo, CWI, and AR strategies.

Photobiomodulation therapy as a tool to prevent hamstring strain injuries by reducing soccer-induced fatigue on hamstring muscles

Muscle fatigue is a potential risk factor for hamstring strain injuries in soccer players. The aim of this study was to verify the effect of photobiomodulation therapy (PBMT) on the hamstrings' muscle fatigue of soccer players during a simulated match. Twelve male amateur soccer players (~ 25 years) participated in this randomized, crossover, double-blinded, placebo-controlled trial. The volunteers were evaluated in two sessions, with a minimum 7-day interval. At each session, volunteers received either PBMT (300 J per thigh) or placebo treatment on the hamstrings prior to the simulated soccer match. Muscle strength and functional capacity were evaluated through isokinetic dynamometry and countermovement jump (CMJ) tests, respectively, before and immediately after the simulated soccer match. Players had lower reductions on hamstring eccentric peak torque [4.85% (ES = 0.31) vs. 8.72% (ES = 0.50)], hamstring-to-quadriceps torque ratio [3.60% (ES = 0.24) vs. 7.75% (ES = 0.50)], and CMJ height [1.77% (ES = 0.09) vs. 5.47% (ES = 0.32)] when treated with PBMT compared to placebo. Magnitude-based inference supports that PBMT promoted 75%, 69%, and 53% chances for beneficial effects on hamstring eccentric peak torque, hamstring-to-quadriceps torque ratio, and CMJ height, respectively, compared to placebo treatment. In conclusion, PBMT applied before a simulated soccer match proved to be effective in attenuating the hamstrings' muscle fatigue. These findings support PBMT as a promising tool to prevent hamstring strain injury in soccer players.

Intravenous Laser Wavelength Irradiation Effect on Interleukins: IL-1α, IL-1β, IL6 in Diabetic Rats

Background and aims

The main purpose of this investigation in Low-Level Laser Therapy (LLLT) on diabetic rats is laser wavelength effect on interleukins: IL-1α, IL-1β, IL6.

Materials Subjects and Methods

At first, diabetes was induced in Wistar rats by streptozotocin (STZ) injection. Then, by intravenous laser therapy, the rats were irradiated by four continuous wave lasers: IR (λ = 808 nm), Red (λ = 638 nm), Green (λ = 532 nm) and Blue (λ= 450 nm) to compare the related laser wavelength effect on different interleukins. The inflammatory parameters were measured 2,6 and 24 hours after laser therapy from blood samples and plotted for different laser wavelengths.

Results

The results show a decrease in all the above parameters by different laser irradiation in comparison to non-radiated diabetic control ones. More importantly with constant laser energy as the laser wavelength decreases, it affects more efficiently on lowering the above parameters.

Conclusions

we can conclude from our data on diabetic rats that in intravenous LLLT, with constant laser energy, shorter wavelengths like Blue (λ= 450 nm) is more effective than longer wavelengths such as Red (λ = 638 nm) and IR (λ = 808 nm) lasers to lower the level of interleukins toward non-diabetic ones.

Immediate effects of photobiomodulation with low-level laser therapy on muscle performance: an integrative literature review

ABSTRACT Purpose: to analyze the influence of low-level laser on muscle performance and to identify the most used dosimetric parameters. Methods: the search for articles was carried out on the PubMed, BVS, Web of Science and SciELO platforms. The articles selected were original ones, with available abstracts and that evaluated the use of photobiomodulation on muscular performance. The data were analyzed according to the author, year of publication, sample, place of application, parameters evaluated, wavelength, dosimetry used and results found. Results: the final sample consisted of 27 articles published between 2008 and 2017. The sample size in the studies ranged from 8 to 60 individuals, aged from 17 to 70 years. A greater use of infrared wavelength, with punctual applications carried out in the path of the muscle, was observed. Regarding the dose, there was a variation from 0.24 to 50 joules per point. Of the total, only 5 (18.5%) studies had not found significant answers for the considered variables. Conclusion: most of the studies pointed out that low-level laser can improve muscle performance. The methodology used in the work was diversified, rendering data compilation difficult, being impossible to set the ideal parameters for this purpose.

Is there a measure for low power laser dose?

Low power lasers have been used successfully for treatment of many diseases in soft and bone tissues. Basic and clinical researches have developed quickly being the scientific basis to therapeutic protocols based on these lasers. However, there are difficulties to compare experimental and clinical results obtained from different researchers because a complicated and intricate list of physical and biological parameters should be checked before the irradiation procedures as well as part of these parameters are omitted or inaccurately reported. This review focuses on the physical and biological parameters proposed to make experimental and clinical protocols accurate and reproducible as well as suggests dose parameters based on biological effects induced by low power lasers. A variety of parameters are reported by different authors and the number of parameter suggested could overcome three dozens. Thus, laser dose and laser dose equivalent are defined based on laser-induced biological effects and suggested as simplified dose parameters for low power lasers. These parameters could simplify and be useful to researchers and clinicians, permitting comparisons and decreasing mistakes and inaccuracies when laser-induced effects are evaluated and compared with those obtained in previous studies. The laser dose and laser dose equivalent could contribute significantly to improve accuracy, effectiveness, and safety of clinical protocols based on low power lasers.

Acute effect of photobiomodulation therapy on handgrip strength of chronic kidney disease patients during hemodialysis

Pre-exercise photobiomodulation therapy (PBMT) reduces fatigue and enhances performance in different populations. However, PBMT benefits have never been tested on chronic kidney disease (CKD) patients, who present muscle weakness, fatigue, and reduced functional performance. The objective of this study was to evaluate the acute effect of three different doses of the PBMT on maximal handgrip strength of CKD patients. Fifteen volunteers (58 ± 8 years, 10 male/5 female) under chronic hemodialysis treatment (6 ± 4 years) participated in a randomized, crossover, double-blind, placebo-controlled trial. Each patient was assessed at four hemodialysis sessions with 1 week interval between evaluations. Placebo or PBMT (cluster probe with five 850 nm/200 mW laser diodes) were applied at three sites along the flexors of the finger (total doses of 60, 90, or 120 J per arm). The maximal handgrip strength was evaluated before and after PBMT/placebo treatment in each session. Repeated measures ANOVA and intraclass correlation coefficients (ICC) confirmed no learning effect on handgrip tests, and high scores for test-retest reliability (ICC scores = 0.89 to 0.95). Significant strength increases occurred after PBMT application with doses of 60 J/arm (4.85%, p = 0.005, ES = 0.32) and 90 J/arm (4.45%, p = 0.013, ES = 0.25), while no changes were detected with placebo or 120 J/arm. In conclusion, in consensus with a recent systematic review, a single bout of the 60 J/arm was the best dose/response for increased strength of the small muscles (handgrip strength). In view of the increasing implementation of exercise programs during hemodialysis, the current study opens a new field for PBMT for CKD patients.

Pre-Exercise Infrared Photobiomodulation Therapy (810 nm) in Skeletal Muscle Performance and Postexercise Recovery in Humans: What Is the Optimal Power Output?

BACKGROUND

Photobiomodulation therapy (PBMT) has recently been used to alleviate postexercise muscle fatigue and enhance recovery, demonstrating positive results. A previous study by our research group demonstrated the optimal dose for an infrared wavelength (810 nm), but the outcomes could be optimized further with the determination of the optimal output power.

OBJECTIVE

The aim of the present study was to evaluate the effects of PBMT (through low-level laser therapy) on postexercise skeletal muscle recovery and identify the best output power.

MATERIALS AND METHODS

A randomized, placebo-controlled double-blind clinical trial was conducted with the participation of 28 high-level soccer players. PBMT was applied before the eccentric contraction protocol with a cluster with five diodes, 810 nm, dose of 10 J, and output power of 100, 200, 400 mW per diode or placebo at six sites of knee extensors. Maximum isometric voluntary contraction (MIVC), delayed onset muscle soreness (DOMS) and biochemical markers related to muscle damage (creatine kinase and lactate dehydrogenase), inflammation (IL-1β, IL-6, and TNF-α), and oxidative stress (catalase, superoxide dismutase, carbonylated proteins, and thiobarbituric acid) were evaluated before isokinetic exercise, as well as at 1 min and at 1, 24, 48, 72, and 96 h, after the eccentric contraction protocol.

RESULTS

PBMT increased MIVC and decreased DOMS and levels of biochemical markers (p < 0.05) with the power output of 100 and 200 mW, with better results for the power output of 100 mW.

CONCLUSIONS

PBMT with 100 mW power output per diode (500 mW total) before exercise achieves best outcomes in enhancing muscular performance and postexercise recovery. Another time it has been demonstrated that more power output is not necessarily better.

Effect of photobiomodulation therapy on oxidative stress markers of gastrocnemius muscle of diabetic rats subjected to high-intensity exercise

This study aimed to determine whether photobiomodulation therapy (PBMT) in diabetic rats subjected to high-intensity exercise interferes with the expression of the oxidative stress marker in the gastrocnemius muscle. Twenty-four male Wistar rats were included in this study comprising 16 diabetic and eight control rats. The animals were allocated into three groups-control, diabetic fatigue, and diabetic PBMT fatigue groups. Diabetes was induced via the intraperitoneal administration of streptozotocin (50 mg/kg). We subsequently assessed blood lactate levels and PBMT. The animals of the diabetic fatigue group PBMT were irradiated before the beginning of the exercises, with dose of 4 J and 808 nm, were submitted to treadmill running with speed and gradual slope until exhaustion, as observed by the maximum volume of oxygen and lactate level. The animals were euthanized and muscle tissue was removed for analysis of SOD markers, including catalase (CAT), glutathione peroxidase (GPx), and 2-thiobarbituric acid (TBARS) reactive substances. CAT, SOD, and GPx activities were significantly higher in the diabetic PBMT fatigue group (p < 0.05) than in the diabetic fatigue group. Outcomes for the diabetic PBMT fatigue group were similar to those of the control group (p > 0.05), while their antioxidant enzymes were significantly higher than those of the diabetic fatigue group. PBMT mitigated the TBARS concentration (p > 0.05). PBMT may reduce oxidative stress and be an alternative method of maintaining physical fitness when subjects are unable to perform exercise. However, this finding requires further testing in clinical studies.

Effect of Phototherapy on Masseter and Anterior Temporal Muscles Before Induction of Fatigue: A Randomized, Sham-Controlled, Blind Clinical Trial

OBJECTIVE

This is a randomized, sham-controlled, blind clinical trial that aimed to evaluate the effect of phototherapy on bite force, mandibular range of motion, sensitivity to palpation, and fatigue in the masseter and anterior temporal muscles of young patients when administered before the induction of fatigue.

MATERIALS AND METHODS

Fifty-two healthy volunteers aged 18-23 years were randomly allocated to a laser group and sham group. Both groups were submitted to a clinical evaluation to record mandibular range of motion, bite force, muscle sensitivity to palpation, and muscle fatigue. The laser group was then submitted to phototherapy (780 nm, 25 J/cm², 50 mW, 20 sec, and 1 J per point) on three points of the masseter and one point of the anterior temporal muscle on each side. The sham group was submitted to the same procedure, but with the device switched off. The volunteers were then instructed to chew two pieces of gum (one on each side) for 6 min, with the pace set by a metronome calibrated to 80 bpm, followed by the reevaluation of all variables. The results were submitted to t-test and Wilcoxon test. A significance level of 5% (p < 0.05) was considered in all analyses.

RESULTS

No statistically significant intergroup or intragroup differences were found for the variables analyzed.

CONCLUSIONS

With the proposed protocol, phototherapy administered before the induction of fatigue did not lead to any changes in bite force and mandibular range of motion, indicating that further studies are needed with different phototherapy dosimetric parameters.

Protective effects of photobiomodulation against resistance exercise-induced muscle damage and inflammation in rats

We investigated whether low-level laser therapy (LLLT) prior to or post resistance exercise could attenuate muscle damage and inflammation. Female Wistar rats were assigned to non-LLLT or LLLT groups. An 830-nm DMC Laser Photon III was used to irradiate their hind legs with 2J, 4J, and 8J doses. Irradiations were performed prior to or post (4J) resistance exercise bouts. Resistance exercise consisted of four maximum load climbs. The load work during a resistance exercise bout was similar between Control (non-LLLT, 225 ± 10 g), 2J (215 ± 8 g), 4J (210 ± 9 g), and 8J (226 ± 9 g) groups. Prior LLLT did not induce climbing performance improvement, but exposure to 4J irradiation resulted in lower blood lactate levels post-exercise. The 4J dose decreased creatine kinase and lactic dehydrogenase levels post-exercise regardless of the time of application. Moreover, 4-J irradiation exposure significantly attenuated tumor necrosis factor alpha, interleukin-6, interleukin-1β, cytokine-induced neutrophil chemoattractant-1, and monocyte chemoattractant protein-1. There was minor macrophage muscle infiltration in 4J-exposed rats. These data indicate that LLLT prior to or post resistance exercise can reduce muscle damage and inflammation, resulting in muscle recovery improvement. We attempted to determine an ideal LLLT dose for suitable results, wherein 4J irradiation exposure showed a significant protective role.

Low-level laser therapy in the management of plantar fasciitis: a randomized controlled trial

This study aimed at estimating the extent to which a combination therapy of low-level laser therapy (LLLT) with exercise and orthotic support (usual care) affects functional ability in the patient with plantar fasciitis (PF) when compared to usual care alone. Participants with PF were randomly allocated into two groups: LLLT (n = 27) and control (n = 22). All the participants received home exercise program with orthotic support. In addition, the LLLT group received a gallium-aluminum-arsenide laser with a 850-nm wavelength for ten sessions, three times a week. Functional outcomes were measured by function subscale of American Orthopedic Foot and Ankle Society Score (AOFAS-F) and 12-min walking test including walking speed, cadence, and activity-related pain using visual analog scale (VAS).The scores were recorded at baseline, third week, and third month after the treatment. Analysis was performed using repeated measures ANOVA and an intention to treat approach using multiple imputations. There was a significant improvement in AOFAS-F total score at 3 weeks in both groups (LLLT, p < 0.001; control, p = 0.002), but the improvements were seen only for the LLLT group for AOFAS-F total score (p = 0.04) and two individual items of AOFAS-F (walking distance (p < 0.001) and walking surface (p = 0.01)) at 3 months. The groups were comparable with each other for both walking speed and cadence at all assessment times (p > 0.05). Both groups showed significant reduction in pain over 3 months (LLLT, p < 0.001; control, p = 0.01); however, the LLLT group had lower pain than the control group at 3 months (p = 0.03). The combination therapy of LLLT with usual care is more effective to improve functional outcomes and activity-related pain when compared to usual care alone.

When is the best moment to apply photobiomodulation therapy (PBMT) when associated to a treadmill endurance-training program? A randomized, triple-blinded, placebo-controlled clinical trial

Photobiomodulation therapy (PBMT) employing low-level laser therapy (LLLT) and/or light emitting diode therapy (LEDT) has emerged as an electrophysical intervention that could be associated with aerobic training to enhance beneficial effects of aerobic exercise. However, the best moment to perform irradiation with PBMT in aerobic training has not been elucidated. The aim of this study was to assess the effects of PBMT applied before and/or after each training session and to evaluate outcomes of the endurance-training program associated with PBMT. Seventy-seven healthy volunteers completed the treadmill-training protocol performed for 12 weeks, with 3 sessions per week. PBMT was performed before and/or after each training session (17 sites on each lower limb, using a cluster of 12 diodes: 4 × 905 nm super-pulsed laser diodes, 4 × 875 nm infrared LEDs, and 4 × 640 nm red LEDs, dose of 30 J per site). Volunteers were randomized in four groups according to the treatment they would receive before and after each training session: PBMT before + PBMT after, PBMT before + placebo after, placebo before + PBMT after, and placebo before + placebo after. Assessments were performed before the start of the protocol and after 4, 8, and 12 weeks of training. Primary outcome was time until exhaustion; secondary outcome measures were oxygen uptake and body fat. PBMT applied before and after aerobic exercise training sessions (PBMT before + PBMT after group) significantly increased (p < 0.05) the percentage of change of time until exhaustion and oxygen uptake compared to the group treated with placebo before and after aerobic exercise training sessions (placebo before + placebo after group) at 4th, 8th, and 12th week. PBMT applied before and after aerobic exercise training sessions (PBMT before + PBMT after group) also significantly improved (p < 0.05) the percentage of change of body fat compared to the group treated with placebo before and after aerobic exercise training sessions (placebo before + placebo after group) at 8th and 12th week. PBMT applied before and after sessions of aerobic training during 12 weeks can increase the time-to-exhaustion and oxygen uptake and also decrease the body fat in healthy volunteers when compared to placebo irradiation before and after exercise sessions. Our outcomes show that PBMT applied before and after endurance-training exercise sessions lead to improvement of endurance three times faster than exercise only.