Effects of Photobiomodulation Therapy on Performance in Successive Time-to-Exhaustion Cycling Tests: A Randomized Double-Blinded Placebo-Controlled Trial.

The goal of this study was to investigate the effects of photobiomodulation therapy (PBMT) on performance, oxygen uptake (VO2) kinetics, and lower limb muscle oxygenation during three successive time-to-exhaustions (TTEs) in cyclists. This was a double-blind, randomized, crossover, placebo-controlled trial study. Sixteen cyclists (~23 years) with a cycling training volume of ~460 km/week volunteered for this study. In the first session, cyclists performed a maximal incremental test to determine maximal oxygen uptake and maximal power output (POMAX). In the following sessions, cyclists performed three consecutive TTEs at POMAX. Before each test, PBMT (135 J/thigh) or a placebo (PLA) was applied to both thighs. VO2 amplitude, O2 deficit, time delay, oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb), and total hemoglobin (tHb) were measured during tests on the right vastus lateralis. The PBMT applied before three successive TTE increased performance of the first and second TTE (~10-12%) tests, speed of VO2 and HHb kinetics during the first test, and increased peripheral muscle oxygenation (increase in HHb and tHb) in the first and second exhaustion tests. However, the PBMT effects were attenuated in the third TTE, as performance and all the other outcomes were similar to the ones from the PLA intervention. In summary, PBMT application increased the first and second successive TTEs, speed of VO2, and muscle oxygenation.

Effects of eccentric-emphasized leg curl intervention on muscle strength imbalance markers in professional soccer players during pre-season.

BACKGROUND: The effects of strength training on muscle strength imbalance are unclear in professional soccer players. As a result, this study examined the effects of an 8-week strength training program comprising eccentric-emphasized prone leg curl adjusted according to the individual strength imbalance status. METHODS: Ten professional soccer players (26.0 ± 3.6 yrs) participated in the study. Players who had a ≥ 10% contralateral imbalance in knee flexors eccentric peak torque (n = 6) performed two additional repetitions per set in the low-strength limb (high-volume, HV) compared to the high-strength limb (low-volume, LV). Isokinetic concentric knee extension and concentric and eccentric knee flexion peak torque (PT) and derived contralateral imbalances and conventional and functional hamstring-to-quadriceps ratios (H:Q) were assessed at baseline and after 8 weeks. Differences at baseline were assessed using paired-sample T-tests, and a two-way (limb x time) repeated measures analysis of covariance (ANCOVA) for changes over time. RESULTS: A significant improvement in the eccentric knee flexion PT was observed in both limbs after 8 weeks (P < 0.05), with greater effects observed in the HV limb (25.0 N m, 95% CI: 15.1-34.9 N m). Significant decreases were also observed in the contralateral imbalances from concentric knee extension and flexion and eccentric knee flexion PT (P < 0.05). Differences were not observed in concentric knee extension and flexion PT (P > 0.05). CONCLUSIONS: A short-term eccentric-emphasized leg curl intervention adjusted by the initial knee flexors eccentric strength was an efficient method to improve knee flexors strength imbalance in professional soccer players.

Effects of omega-3 supplementation on muscle damage after resistance exercise in young women: a randomized placebo-controlled trial.

BACKGROUND: Omega-3 is a nutritional strategie that have been used to recover muscles from exercise-induced muscle damage in a preventive perspective. AIM: To verify whether omega-3 (ω-3) supplementation after a session of resistance exercise facilitates muscle recovery in women undergoing a balanced diet. METHODS: This clinical trial was registered under the number NCT02839525. Thirty healthy women (22.2 ± 3.3 years) participated in this double-blinded, placebo-controlled trial. They were randomly distributed into ω-3 (n=15) and placebo (n=15) groups. They ingested ω-3 fish oil (3200 mg/day) or placebo (olive oil) at the dinner after the exercise bout (10 sets of 10 unilateral eccentric contractions in a knee extension chair), as well as at lunch for the three subsequent days. In addition, both groups followed a balanced diet along the four days. Muscle soreness and maximal isometric and isokinetic voluntary contractions were assessed immediately before, and 24, 48, and 72 hours after the resistance exercise. MAIN FINDINGS: There was no significant group-time interaction for any outcome. Participants presented increased levels of muscle soreness and reduced muscle strength capacity along the three days after exercise. There was no difference between placebo and ω-3 groups. CONCLUSION: Supplementation of ω-3 fish oil for three days after resistance exercise provided no additional benefits compared to placebo supplementation on recovery of healthy young women following a balanced diet.

Alternating Current Is More Fatigable Than Pulsed Current in People Who Are Healthy: A Double-Blind, Randomized Crossover Trial.

OBJECTIVE: Tolerance level and rapid fatigue onset are limitations in the use of neuromuscular electrical stimulation (NMES) as an electrotherapeutic resource in rehabilitation and training protocols; however, it is unclear if pulsed current (PC) and alternating current (AC) produce different fatigue levels when applied at submaximal contraction level. The purpose of this study was to compare fatigue and discomfort levels between PC and AC during a submaximal contraction protocol in people who are healthy. METHODS: In this double-blind, randomized crossover trial conducted in a laboratory setting, 30 male volunteers [23.23 years of age (SD = 4.59)] performed 2 submaximal fatigue protocols (with a 7-day interval) in a randomized order: PC (pulse duration = 2 milliseconds, pulse frequency = 100 Hz) and AC (2.5 kHz, pulse duration = 0.4 milliseconds, burst frequency = 100 Hz). NMES currents were applied to the knee extensor motor point of the dominant limb. The NMES protocol consisted of 80 evoked contractions (time on:off = 5:10 seconds) and lasted 20 minutes. The current was maintained at a constant intensity throughout the NMES protocol. The primary outcome measures were maximal voluntary isometric contraction, fatigue index (evoked torque decline), fatigability (number of contractions for a 50% drop in evoked-torque from the protocol start), total evoked torque-time integral (TTI), decline in TTI, and discomfort level. RESULTS: AC at 2.5 kHz demonstrated higher maximal voluntary isometric contraction decline post-fatigue, higher fatigue index, higher fatigability (ie, fewer contractions to reach the 50% evoked torque decline from the protocol start), smaller total TTI, and higher TTI decline compared with PC. No between-currents difference was observed in discomfort level. CONCLUSION: PC is less fatigable than AC at 2.5 kHz. IMPACT: Based on this study, PC is the preferred current choice when the NMES goal is to generate higher muscle work, higher mechanical load, and smaller fatigability during training both for athletes who are healthy and for rehabilitation programs for people with disease or injury.

Photobiomodulation Therapy Partially Restores Cartilage Integrity and Reduces Chronic Pain Behavior in a Rat Model of Osteoarthritis: Involvement of Spinal Glial Modulation.

OBJECTIVE: Chronic pain associated with osteoarthritis (OA) often leads to reduced function and engagement in activities of daily living. Current pharmacological treatments remain relatively ineffective. This study investigated the efficacy of photobiomodulation therapy (PBMT) on cartilage integrity and central pain biomarkers in adult male Wistar rats. DESIGN: We evaluated the cartilage degradation and spinal cord sensitization using the monoiodoacetate (MIA) model of OA following 2 weeks of delayed PBMT treatment (i.e., 15 days post-MIA). Multiple behavioral tests and knee joint histology were used to assess deficits related to OA. Immunohistochemistry was performed to assess chronic pain sensitization in spinal cord dorsal horn regions. Furthermore, we analyzed the principal components related to pain-like behavior and cartilage integrity. RESULTS: MIA induced chronic pain-like behavior with respective cartilage degradation. PBMT had no effects on overall locomotor activity, but positive effects on weight support (P = 0.001; effect size [ES] = 1.01) and mechanical allodynia (P = 0.032; ES = 0.51). Greater optical densitometry of PBMT-treated cartilage was evident in superficial layers (P = 0.020; ES = 1.34), likely reflecting the increase of proteoglycan and chondrocyte contents. In addition, PBMT effects were associated to decreased contribution of spinal glial cells to pain-like behavior (P = 0.001; ES = 0.38). CONCLUSION: PBMT during the chronic phase of MIA-induced OA promoted cartilage recovery and reduced the progression or maintenance of spinal cord sensitization. Our data suggest a potential role of PBMT in reducing cartilage degradation and long-term central sensitization associated with chronic OA.

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.

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.

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 with lower fatigue, which may facilitate the performance of additional sets (i.e., higher training volume).

Effect of Photobiomodulation Therapy in the 1500 m Run: An Analysis of Performance and Individual Responsiveness.

Objective: The aims of this study were to verify the effects of photobiomodulation therapy (PBMT) on time trial run performance over 1500 m, as well as on individual responsiveness of recreative runners. Materials and methods: Nineteen recreationally trained runners participated in a randomized, crossover, double-blind placebo-controlled trial. The study was divided in four sessions: (1) incremental maximal running test; (2) 1500 m run control (without placebo or PBMT); and (3, 4) PBMT or placebo before 1500 m run. PBMT or placebo was applied over 14 sites per lower limb immediately before time trial run using a mixed wavelength device (33 diodes: 5 LASERs of 850 nm, 12 LEDs of 670 nm, 8 LEDs of 880 nm, and 8 LEDs with 950 nm). PBMT delivered 30 J per site, with a total energy dose of 840 J. Physiological variables [maximal oxygen uptake (VO2MAX), velocity associated to VO2MAX (vVO2MAX), peak of velocity, and respiratory compensation point (RCP)] were assessed during incremental maximal test. During 1500 m races we accessed the following: time, heart rate, and lower limb rate perception exertion per lap, total time, and blood lactate concentration ([Lac]). Results: PBMT had no significant difference and likely trivial effect for performance in the total time trial run over 1500 m compared to placebo. In the responsiveness analyses, 10 participants positively responded to PBMT, whereas total time reduced for responders (-10.6 sec; -3.18%) and increased for nonresponders (+6.0 sec; +1.73%). Responders presented higher aerobic parameters (VO2MAX and RCP) than nonresponders. Moreover, responders had lower time per lap and [Lac] (1 and 3 min) when PBMT was applied. Conclusions: PBMT applied immediately before running in noncontrolled environment was not able to improve the 1500 m performance of recreationally trained runners. However, responders to PBMT presented higher aerobic capacity than nonresponders.

Electrophysical agents in clinical practice of orthopedic and sports physical therapists in Brazil / Agentes eletrofísicos na prática clínica de fisioterapeutas ortopédicos e esportivos no Brasil / Agentes electrofísicos en la práctica clínica de fisioterapeutas ortopédicos y deportivos en Brasil

ABSTRACT Studies have described the use of electrophysical agents (EPA) by physical therapists worldwide. However, the use of EPA by Brazilian physical therapists remains undetermined. This study aims to describe the availability, use, and perception about EPA by orthopedic and sports physical therapists in Brazil. Professionals of the area were invited to answer an online questionnaire. Demographic data and information regarding the availability, use and perception about EPA in their current clinical practice were asked. Out of 376 physical therapists included in this study, 89% declared to use EPA in clinical practice. Sensory electrotherapy with pulsed current (TENS), therapeutic ultrasound, excitomotor electrotherapy with pulsed current (FES/NMES), and cryotherapy are available for more than 3/4 of interviewees. Scientific articles and clinical experience, respectively, are the most influential factors for the choice of EPA. Ultrasound is the most frequently used EPA, followed by TENS, cryotherapy, photobiomodulation, hot packs, and FES/NMES. The top-five most useful EPA in clinical practice chosen by physical therapists are: (1) ultrasound; (2) photobiomodulation; (3) TENS; (4) cryotherapy; and (5) FES/NMES. In conclusion, EPA are widely used by orthopedic and sports physical therapists in Brazil. Therapeutic ultrasound, TENS, FES/NMES, photobiomodulation, cryotherapy, and hot packs are the most used EPA in clinical practice of these physiotherapists.

RESUMO Estudos têm descrito a utilização de agentes eletrofísicos (AE) por fisioterapeutas ao redor do mundo. No entanto, o uso de AE por fisioterapeutas brasileiros permanece inexplorado. O objetivo deste estudo é descrever o acesso, a utilização e a percepção sobre os AE de fisioterapeutas ortopédicos e esportivos no Brasil. Os profissionais foram convidados a responder um questionário on-line. Foram solicitados dados demográficos e informações sobre o acesso, utilização e percepção dos profissionais sobre os AE na prática clínica. Dentre os 376 fisioterapeutas incluídos, 89% declararam ser usuários de AE na prática clínica. Eletroterapia sensorial com corrente pulsada (TENS), ultrassom terapêutico, eletroterapia excitomotora com corrente pulsada (FES/NMES) e crioterapia são acessíveis para mais de 3/4 dos participantes. Artigos científicos e experiência clínica são os fatores de maior influência na escolha por AE. O ultrassom é o AE mais frequentemente utilizado, seguido por Tens, crioterapia, fotobiomodulação, bolsas quentes e FES/NMES. Os cinco AE elencados pelos fisioterapeutas como mais úteis na prática clínica são: (1) ultrassom; (2) fotobiomodulação; (3) TENS; (4) crioterapia; e (5) FES/NMES. Em conclusão, os AE são largamente usados pelos fisioterapeutas ortopédicos e esportivos no Brasil. Ultrassom terapêutico, TENS, FES/NMES, fotobiomodulação, crioterapia e bolsas quentes são os AE mais usados na prática clínica desses fisioterapeutas.

RESUMEN Los estudios ya han descrito el uso de agentes electrofísicos (AE) por fisioterapeutas en todo el mundo. Todavía no se ha explorado el uso de los AE por fisioterapeutas brasileños. El presente estudio tuvo como objetivo describir el acceso, el uso y la percepción sobre los AE por fisioterapeutas ortopédicos y deportivos en Brasil. Se invitó a los profesionales para responder a un cuestionario en línea. Se solicitaron los datos demográficos e informaciones sobre el acceso, el uso y la percepción de profesionales sobre los AE en la práctica clínica. Entre los 376 fisioterapeutas incluidos, el 89% declararon utilizar los AE en la práctica clínica. La electroterapia sensorial con corriente pulsada (TENS), el ultrasonido terapéutico, la electroterapia excitomotora con corriente pulsada (FES/NMES) y la crioterapia son accesibles para más de 3/4 de los participantes. Los artículos científicos y la experiencia clínica son los factores que más influyeron en la elección de los AE. El ultrasonido es el AE más utilizado, seguido de Tens, crioterapia, fotobiomodulación, bolsas calientes y FES/NMES. Los cinco AE más útiles en la práctica clínica enumerados por los fisioterapeutas fueron: (1) ultrasonido; (2) fotobiomodulación; (3) TENS; (4) crioterapia; y (5) FES/NMES. Los AE son ampliamente utilizados por los profesionales de la ortopedia y el deporte en Brasil. El ultrasonido terapéutico, TENS, FES/NMES, fotobiomodulación, crioterapia y bolsas calientes son los AE más utilizados en la práctica clínica por estos fisioterapeutas.

Effects of low-level laser therapy on hamstring strain injury rehabilitation: A randomized controlled trial.

OBJECTIVES: To evaluate the effects of low-level laser therapy (LLLT) on functional rehabilitation following hamstring strain injury (HSI) in amateur athletes treated with an exercise-based rehabilitation program. DESIGN: Randomized controlled trial. METHODS: Male athletes (18-40 years old) who sustained HSI were randomized in LLLT or placebo groups. All patients were engaged in the same exercise-based rehabilitation program until they met specific criteria to return to sport. Hamstring muscles were treated with LLLT or placebo immediately after each rehabilitation session. The primary outcome was time-to-return to sport. Secondary outcomes were the number of rehabilitation sessions, hamstring flexibility, hamstring strength, and re-injury rate. RESULTS: Twenty-four athletes began rehabilitation, and 22 (11 per group) completed the study schedule. Participants of LLLT and placebo groups had similar age, body size, injury characteristics, and baseline levels of hamstring flexibility and strength. The two groups increased flexibility and strength similarly throughout the rehabilitation program. Time-to-return to sport was the same for athletes treated with LLLT (23 ± 9 days) and placebo (24 ± 13 days). There were no re-injuries within 6 months after return to sport. CONCLUSION: LLLT, as used in this study, did not optimize functional rehabilitation following HSI in amateur athletes treated with an exercise-based rehabilitation program.

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.

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.

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.

Eccentric training combined to neuromuscular electrical stimulation is not superior to eccentric training alone for quadriceps strengthening in healthy subjects: a randomized controlled trial.

BACKGROUND: Both eccentric training and neuromuscular electrical stimulation (NMES) are used for quadriceps strengthening. However, the effects of these interventions combined are unclear. OBJECTIVES: To compare the effects of eccentric training combined to NMES and eccentric training alone on structure, strength, and functional performance of knee extensor muscles of healthy subjects. METHODS: This is a three-arm, single-blinded, randomized controlled trial. Forty-three volunteers (18-35 years) completed the full study schedule: control group (n=15); eccentric training group (ECC; n=15); and eccentric training combined to NMES group (ECC+NMES; n=13). Eccentric training program was performed twice a week for 6 weeks. A biphasic pulsed current (400µs; 80Hz; maximal tolerated intensity) was applied simultaneously to voluntary exercise for ECC+NMES group. Muscle structure (ultrasonography of vastus lateralis - VL, and rectus femoris - RF), strength (isokinetic dynamometry) and functional capacity (single hop test) were assessed before and after the training program by blinded researchers to groups allocation. RESULTS: Control group had no changes throughout the study in any outcome. Eccentric training (with or without NMES) did not affect concentric peak torque, hop test, and VL pennation angle (effect sizes>0.2). ECC and ECC+NMES programs generated significant adaptations (small to moderate effect sizes) on isometric (8-11%) and eccentric (13%) peak torques, VL muscle thickness (5%), VL fascicle length (5-8%), RF muscle thickness (8-9%), RF pennation angle (-2%), and RF fascicle length (12%). CONCLUSION: NMES combined to eccentric training did not influence consistently the type or magnitude of adaptations provoked by knee extensor eccentric training alone in healthy subjects.

Acute Effects of Low-Level Laser Therapy on Patients' Functional Capacity in the Postoperative Period of Coronary Artery Bypass Graft Surgery: A Randomized, Crossover, Placebo-Controlled Trial.

OBJECTIVE: The aim of this study was to evaluate the acute effects of low-level laser therapy (LLLT) on the functional capacity to exercise tested by incremental shuttle walking test (ISWT) after coronary artery bypass graft (CABG) surgery. METHODS: Fifteen male patients (60 ± 9 years) were crossed over during the experiment, to compare the outcomes after active LLLT and placebo LLLT treatments. LLLT (850 nm, 200 mW, 30 J to each point, resulting in a total of 240 J per quadriceps muscle), using a multidiode cluster (five spots; 6 J/spot) in eight points per leg was performed 3 min before the ISWT. We analyzed distance walked, Borg scale of perceived exertion, heart rate, and brachial arterial blood pressure. Markers of tissue damage [lactate dehydrogenase (LDH)] and oxidative stress [lipid peroxidation, total thiol levels, and antioxidant enzyme activity of superoxide dismutase (SOD) and catalase (CAT)] were also measured in peripheral blood. RESULTS: Comparison of the distances walked revealed no significant differences between the LLLT and placebo LLLT groups (p = 0.779). Regarding the Borg scale (p = 0.567), heart rate (p = 0.506) as well as systolic and diastolic blood pressure (p = 0.164 and p = 0.140, respectively), no differences were observed between LLLT and placebo LLLT groups. Application of LLLT was not able to change levels of LDH (p = 0.214), oxidative lipid damage (p = 0.733), total thiol levels (p = 0.925), SOD (p = 0.202), and CAT (p = 0.825) enzyme activities. CONCLUSIONS: Acute LLLT improved neither functional capacity to exercise nor the markers of oxidation after CABG. TRIAL REGISTRATION: Registered as a clinical trial (NCT02688426).

Dose-response effect of photobiomodulation therapy on neuromuscular economy during submaximal running.

The purpose of this study was to verify the photobiomodulation therapy (PBMT) effects with different doses on neuromuscular economy during submaximal running tests. Eighteen male recreational runners participate in a randomized, double-blind, and placebo-controlled trial, which each participant was submitted to the same testing protocol in five conditions: control, placebo, and PBMT with doses of 15, 30, and 60 J per site (14 sites in each lower limb). The submaximal running was performed at 8 and 9 km h-1 during 5 min for each velocity. Muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), and gastrocnemius lateralis (GL) was collected during the last minute of each running test. The root mean square (RMS) was normalized by maximal isometric voluntary contraction (MIVC) performed a priori in an isokinetic dynamometer. The RMS sum of all muscles (RMSLEG) was considered as main neuromuscular economy parameter. PBMT with doses of 15, 30, and 60 J per site [33 diodes = 5 lasers (850 nm), 12 LEDs (670 nm), 8 LEDs (880 nm), and 8 LEDs (950 nm)] or placebo applications occurred before running tests. For the statistical analysis, the effect size was calculated. Moreover, a qualitative inference was used to determine the magnitude of differences between groups. Peak torque and RMS during MIVCs showed small effect sizes. According to magnitude-based inference, PBMT with dose of 15 J per site showed possibly and likely beneficial effects on neuromuscular economy during running at 8 and 9 km h-1, respectively. On other hand, PBMT with doses of 30 and 60 J per site showed possible beneficial effects only during running at 9 km h-1. We concluded that PBMT improve neuromuscular economy and the best PBMT dose was 15 J per site (total dose of 420 J).

Effects of low-level laser therapy applied before or after plyometric exercise on muscle damage markers: randomized, double-blind, placebo-controlled trial.

Promising effects of phototherapy on markers of exercise-induced muscle damage has been already demonstrated in constant load or isokinetic protocols. However, its effects on more functional situations, such as plyometric exercises, and when is the best moment to apply this treatment (pre- or post-exercise) remain unclear. Therefore, the purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before or after plyometric exercise on quadriceps muscle damage markers. A randomized, double-blinded, placebo-controlled trial was conducted with 24 healthy men, 12 at pre-exercise treatment group and 12 at post-exercise treatment group. Placebo and LLLT (810 nm, 200 mW per diode, 6 J per diode, 240 J per leg) were randomly applied on right/left knee extensor muscles of each volunteer before/after a plyometric exercise protocol. Muscular echo intensity (ultrasonography images), soreness (visual analogue scale - VAS), and strength impairment (maximal voluntary contraction - MVC) were assessed at baseline, 24, 48, and 72 h post-exercise. Legs treated with LLLT before or after exercise presented significantly smaller increments of echo intensity (values up to 1 %) compared to placebo treatments (increased up to ∼7 %). No significant treatment effect was found for VAS and MVC, although a trend toward better results on LLLT legs have been found for VAS (mean values up to 30 % lesser than placebo leg). In conclusion, LLLT applied before or after plyometric exercise reduces the muscle echo intensity response and possibly attenuates the muscle soreness. However, these positive results were not observed on strength impairment.

Effects of neuromuscular electrical stimulation and low-level laser therapy on neuromuscular parameters and health status in elderly women with knee osteoarthritis: A randomized trial.

OBJECTIVE: To determine the effects of neuromuscular electrical stimulation and low-level laser therapy on neuromuscular parameters and health status in elderly subjects with knee osteoarthritis. DESIGN: A randomized evaluator-blinded clinical trial. SUBJECTS: Forty-five elderly women with knee osteoarthritis. METHODS: Subjects were randomized into 1 of the following 3 intervention groups: electrical stimulation group (18-32 min pulsed current, stimulation frequency 80 Hz, pulse duration 400 µs, stimulation intensity 40% of maximal isometric voluntary contraction), laser group (dose 4-6 J per point, 6 points at the knee joint) or combined group (electrical stimulation plus laser therapy). The outcomes included muscle thickness and anatomical cross-sectional area (ultrasonography), knee extensors' electrical activity (electromyography), torque (dynamometry) and health status (Western Ontario and McMaster Universities Osteoarthritis Index). All groups underwent a 4-week control period (without intervention) followed by an 8-week intervention period. RESULTS: Muscle thickness and anatomical cross-sectional area increased in the electrical stimulation and combined groups. All groups presented similar improvements in torque, electrical activity and health status. CONCLUSION: Electrical stimulation alone or in combination with laser therapy generated positive effects on all evaluated parameters. Laser therapy increased health status and electrical activity, but had no effect on muscle mass.

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

PURPOSE: Eccentric training has been popularized for physical conditioning and prevention/rehabilitation of musculoskeletal disorders, especially due to the expressive responses in terms of muscular strength gain. In view of evidence that low-level laser therapy (LLLT) is able to increase exercise performance and accelerate post-exercise recovery, the aim of this study was to verify the effect of LLLT on hypertrophy and strengthening of knee extensor muscles submitted to eccentric training. METHOD: Thirty healthy male subjects were randomized into three groups: Control Group (CG), Training Group (TG) and Training + LLLT Group (TLG). CG received no intervention, while TG and TLG were engaged on an 8-week knee extensor isokinetic eccentric training program. Only subjects from TLG were treated with LLLT (wavelength = 810 nm; power output = 200 mW; total dosage = 240 J) before each training session. Knee extensor muscle thickness and peak torque were assessed through ultrasonography and isokinetic dynamometry, respectively. RESULTS: CG presented no changes in any variable throughout the study, while eccentric training led to significant increases in muscle thickness and peak torque in TG and TLG. Subjects from TLG reached significantly higher percent changes compared to subjects from TG for sum of muscles' thicknesses (15.4 vs. 9.4%), isometric peak torque (20.5 vs. 13.7%), and eccentric peak torque (32.2 vs. 20.0%). CONCLUSION: LLLT applied before eccentric training sessions seems to improve the hypertrophic response and muscular strength gain in healthy subjects.