Article

Light-emitting diode therapy (LEDT) before matches prevents increase in creatine kinase with a light dose response in volleyball players

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Abstract

Low-level laser (light) therapy (LLLT) has been applied over skeletal muscles before intense exercise (muscular pre-conditioning) in order to reduce fatigue and muscle damage (measured by creatine kinase, CK) in clinical trials. However, previous exercise protocols do not exactly simulate the real muscle demand required in sports. For this reason, the aim of this randomized and double-blind placebo-controlled trial was to investigate whether light-emitting diode therapy (LEDT) applied over the quadriceps femoris muscles, hamstrings, and triceps surae of volleyball players before official matches could prevent muscle damage (CK) with a dose response, establishing a therapeutic window. A professional male volleyball team (12 athletes) was enrolled in this study, and LEDT was applied before 4 matches during a national championship. LEDT used an array of 200 light-emitting diodes (LEDs) arranged in 25 clusters of 4 infrared LEDs (850 ± 20 nm; 130 mW) and 25 clusters of 4 red LEDs (630 ± 10 nm; 80 mW). Athletes were randomized to receive one of four different total doses over each muscle group in a double-blind protocol: 105 J (20 s), 210 J (40 s), 315 J (60 s), and placebo (no light for 30 s). CK in blood was assessed 1 h before and 24 h after each match. LEDT at 210 J avoided significant increases in CK (+10 %; P = 0.993) as well as 315 J (+31 %, P = 0.407). Placebo (0 J) allowed a significant increase in CK (+53 %; P = 0.012) as well as LEDT at 105 J (+59 %; P = 0.001). LEDT prevented significant increases of CK in blood in athletes when applied before official matches with a light dose response of 210-315 J, suggesting athletes might consider applying LEDT before competition.

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... 7,8 In recent years, there have been an increasing number of studies discussing the use of light interventions as a recovery strategy. 9 The terms phototherapy or photobiomodulation have been used to define these interventions that can differentiate as to their light source [low-level laser therapy (LLLT) and light-emitting diode therapy (LEDT)]. [9][10][11] Recent systematic reviews have reported positive effects on muscle soreness, 12 improved fatigue response, [12][13][14] with increased repetition numbers 13,14 and delayed time to exhaustion, 13,14 improved performance, 13,14 and reduced blood lactate [13][14][15] and CK levels. ...
... 9 The terms phototherapy or photobiomodulation have been used to define these interventions that can differentiate as to their light source [low-level laser therapy (LLLT) and light-emitting diode therapy (LEDT)]. [9][10][11] Recent systematic reviews have reported positive effects on muscle soreness, 12 improved fatigue response, [12][13][14] with increased repetition numbers 13,14 and delayed time to exhaustion, 13,14 improved performance, 13,14 and reduced blood lactate [13][14][15] and CK levels. 3,13 The effects of phototherapy are associated to the other variables and not to light source. ...
... All randomized controlled trials were provided from Brazil, 8 6,9,[25][26][27][28][29][30] studies used a crossover design and 6 4,5,20,31-33 parallel groups. Publication date of the included studies ranged from 2009 to 2016. ...
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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.
... Twenty-one of the included studies performed crossover designs, and 18 were parallel trials ( Table 1). The authors of 16 studies were contacted by e-mail for additional information, 11 authors (68.75%) provided the required data [28, 30, 31, 38, 43, 48-51, 53, 55], with 1 (6.25%) answering that they did not have the information anymore [34], and 4 authors (31.25%) did not answer [25,32,36,56]. ...
... Furthermore, exercises encompassing dynamic concentric contractions with weights or workload machines were proposed, generally involving the quadriceps or biceps brachii muscles [31,36,38,40,42,43,49,52]. Authors also used plyometric exercises [33,46], sport-specific test [48,55], or matches [56], and only one used an electric stimulation protocol [34]. ...
... Some studies evaluated the effects of photobiomodulation therapy in the field with specific sports testing [48,55] or matches [56]. Positive effects were found in the study conducted by Ferraresi et al. [56] in preventing increases in CK activity when photobiomodulation therapy was applied before four volleyball matches. ...
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Researches have been performed to investigate the effects of phototherapy on improving performance and reduction of muscular fatigue. However, a great variability in the light parameters and protocols of the trials are a concern to establish the efficacy of this therapy to be used in sports or clinic. The aim of this study is to investigate the effectiveness, moment of application of phototherapy within an exercise protocol, and which are the parameters optimally effective for the improvement of muscular performance and the reduction of muscular fatigue in healthy people. Systematic searches of PubMed, PEDro, Cochrane Library, EMBASE, and Web of Science databases were conducted for randomized clinical trials to March 2017. Analyses of risk of bias and quality of evidence of the included trials were performed, and authors were contacted to obtain any missing or unclear information. We included 39 trials (861 participants). Data were reported descriptively through tables, and 28 trials were included in meta-analysis comparing outcomes to placebo. Meta-analysis was performed for the variables: time until reach exhaustion, number of repetitions, isometric peak torque, and blood lactate levels showing a very low to moderate quality of evidence and some effect in favor to phototherapy. Further investigation is required due the lack of methodological quality, small sample size, great variability of exercise protocols, and phototherapy parameters. In general, positive results were found using both low-level laser therapy and light-emitting diode therapy or combination of both in a wavelength range from 655 to 950 nm. Most of positive results were observed with an energy dose range from 20 to 60 J for small muscular groups and 60 to 300 J for large muscular groups and maximal power output of 200 mW per diode.
... These trials have used constant load [16,[19][20][21] or isokinetic [17,18] exercise protocols to induce muscle damage. Since its practical application may be limited as it does not reproduce sport activities, efforts have been made to evaluate the effects of phototherapy front to more functional tasks, such as cycling [22,23], running [24], and even a volleyball match [25]. However, these investigations assessed muscle damage solely through CK levels and with a single time point few minutes [22][23][24] or 24 h [25] after exercise, which limits the understanding of phototherapy effects on muscle response to damage induced by functional exercises. ...
... Since its practical application may be limited as it does not reproduce sport activities, efforts have been made to evaluate the effects of phototherapy front to more functional tasks, such as cycling [22,23], running [24], and even a volleyball match [25]. However, these investigations assessed muscle damage solely through CK levels and with a single time point few minutes [22][23][24] or 24 h [25] after exercise, which limits the understanding of phototherapy effects on muscle response to damage induced by functional exercises. ...
... Furthermore, discussion about the differences between LLLT and LEDT can be raised up here. On one hand, there is the idea that Blight is light^; thus, there is no big difference between the light sources to prevent exercise-induced muscle damage if the total dose applied per muscle group is adequate [25]. On the other hand, it has been currently suggested that therapeutic advantage can be achieved if different wavelengths and/or light sources are applied at the same time [17,33,35]. ...
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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.
... The elimination process left 24 eligible trials. [2][3][4][5][6][7][8][9][10]12,[16][17][18][19][20][21][22][25][26][27]32,35,37,39 The characteristics of the 24 included trials are shown in Appendix Table A1 (available in the online version of this article). Ten of them were RCTs, [2][3][4]6,9,10,19,27,36,40 whereas others were crossover trials. ...
... [2][3][4][5][6][7][8][9][10]12,[16][17][18][19][20][21][22][25][26][27]32,35,37,39 The characteristics of the 24 included trials are shown in Appendix Table A1 (available in the online version of this article). Ten of them were RCTs, [2][3][4]6,9,10,19,27,36,40 whereas others were crossover trials. These trials were published between 2008 and 2020, with sample sizes ranging from 6 to 40. ...
... In summary, 14 trials were graded as low risk for overall bias risk 2,3,5,6,8,[17][18][19][20][21][22]27,32,38 ; the other 10 trials had overall bias risk. 4,7,9,10,12,16,25,26,36,40 ...
Article
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 VO 2 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.
... Ten articles were discarded at the stage of full-text review, and 20 studies were finally identified and included in the analysis of the efficacy of laser therapy in adult patients with exercise-induced fatigue. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] Studies were excluded for the following reasons: if the subjects received other therapies, the outcome of interest was unavailable, and the study reported same populations. A manual search of the reference lists of these trials did not yield any new eligible trials. ...
... Of these 20 trials, the study quality was evaluated using the Jadad scale. Overall, 3 trials presented a score of 5, [25,33,39] 8 trials had a score of 4, [24,26,29,32,34,37,41,42] and the remaining 9 trials had a score of 3. [27,28,30,31,35,36,38,40,43] A total of 6 trials displayed data for the effect of laser therapy on the level of lactate. The pooled WMD showed a 0.19 mmol/L reduction in lactate level, while this reduction was not statistically significant (WMD: À0.19; 95% CI: À0.52-0.13; ...
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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.
... More recent studies [25,26] observed modifications of Cox in a time window of 5 to 24 min after muscle irradiation. Conversely, De Brito et al. [27] and Ferraresi et al. [28] state that the application of photobiomodulation therapy generates a tissue effect in 24 to 48 h. ...
... Photobiomodulation can be considered an ergogenic resource and is very well consolidated in the literature. Its effects are directly related to increased ATP synthesis by the absorption of the photons released by PBMT and their absorption by the chromophores present in cytochrome c-oxidase, inside the electron transport chain; consequently there are decreased oxidative stress increased local microcirculation, [5,28]. Several systematic reviews recommend its use, despite the issues involved in the ideal parameters [4,7]. ...
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Analyze the effects of sequential application of photobiomodulation therapy (PBMT) at different wavelengths on the performance of cycling athletes. Cyclists (48 male, mean age 33.77 years) underwent a performance evaluation through an incremental test, VO2max, blood lactate analysis, perception of effort, infrared thermography, and isokinetic evaluations. Photobiomodulation (180 J) with infrared (IR 940 ± 10 nm), red (RED 620 ± 10 nm), mixed Red, and IR (RED/IR 620 + 940 nm) or Sham (disabled device) intervention occurred on three consecutive days and was applied to the quadriceps femoris bilaterally. Reevaluations were performed 24 h after the last application, with 1 week of follow-up. A significance level of 5% was adopted, and the effect size (ES) was calculated by Cohen’s d. Results: There were no significant differences in the analyzed variables under any experimental condition (p > 0.005), but a moderate effect size was observed for torque peak at 60°/s on left lower limb (LLL) (ES = 0.67), average power at 60°/s of the right lower limb (RLL) (0.73), and LLL (ES = 0.65) and a considerable effect size in torque peak at 60°/s of the RLL (ES = 0.98) in the IR/RED group compared with sham 24 h after the last application. Moreover, a large effect size was observed for total time to exhaustion (ES = 1.98) and for VO2max (ES = 6.96), and a moderate effect size was seen for anaerobic threshold (ES = 0.62) in the IR/RED group compared with sham. Photobiomodulation, when not associated with training, was not able to produce a cumulative effect on the performance of cycling athletes. However, the association of two wavelengths seems to be better for increased performance. ClinicalTrials.gov Identifier: NCT03225976
... The use of light therapy has gained prominence in the last decade [20]. The parameters used in therapy are of utmost importance because, depending on the condition or purpose of therapy, the wavelength, power, energy applied, and time of application are different. ...
... Leal Junior et al. [23] used a cluster of 69 diode LEDs (34 red; 35 infrared) for 2 min and 30 s to radiate 417 J (10 mW power for red LED and 30 mW for infrared), totaling 1390 mW. Ferraresi et al. [20] used a 200-diode LED blanket (100 red and 100 infrared) for 20 s to apply 105 J of power (80 mW red and 130 mW infrared power), totaling 5250 mW. In the study by Santos Maciel et al. [26], the energy of 23.49 ...
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Introduction: Effectiveness of light-emitting diode (LED) in biological tissue is due to the correct application of physical parameters. However, most studies found do not provide complete information on the physical characteristics of the diodes. It is necessary to carefully evaluate the diode parameters so that the results of research with this feature can be reproduced. The objective of this study was to develop a light-emitting device using LED, with proper measurements for application in clinical research. It was used 267 LEDs, powered with 12-V voltage and fixed on a plate of ethylene-vinyl acetate (25 × 42 cm), equidistant at 1.0 cm. For the calculation of red and infrared irradiation, a spectrometer was used, and the data were processed in routines implemented in the OriginPro 8.5.0 SR1 Software. The irradiance was determined by the integration of the spectral irradiation in the LED emission region. The red LED has a wavelength of 620 ± 10 nm, a power density of 52.86 mW/cm2, power of 6.6 mW, and total power of 1.76 W on the device. The infrared LED has a wavelength of 940 ± 10 nm, power density 33.7 mW/cm2, power of 6 mW, and total power of 1.6 W on the device. The LED characterization enables the generation and application of energy with greater precision and reproducibility. Besides, it is a light source, a device capable of framing large areas, reducing the time and cost of the application in different clinical conditions related to neuromuscular performance or rehabilitation.
... Studies have progressed to more dynamic protocols, such as such as in-game competitions (De Marchi et al., 2019;Dornelles et al., 2019), sport-specific tests (Pinto et al., 2016), running (Malta et al., 2016(Malta et al., , 2018Dellagrana et al., 2018;Peserico et al., 2019), plyometrics (Fritsch et al., 2016), and cycling (Teles et al., 2015;Malta et al., 2018). In addition, research has examined highly-trained sample populations, such as athletes in jiu-jitsu (Follmer et al., 2018), judo (Orssatto et al., 2019), volleyball (Ferraresi et al., 2015;da Cunha et al., 2019;Vieira et al., 2019), rugby (Pinto et al., 2016), water polo (Zagatto et al., 2016), and futsal (De Marchi et al., 2019). Much of the data support the ergogenic effect of PBMT, including reduced CK post-competition (De Marchi et al., 2019), improved time to exhaustion (Follmer et al., 2018), reduced muscle fatigue (Dornelles et al., 2019), improved rate of perceived exertion, and improved running economy . ...
... This accelerated ATP synthesis subsequently increases the proliferation of myoregulatory factors, such as myogenin and MRF4, which are integral to the formation of mature muscle fibers and muscle repair process (Alves et al., 2014). For athletes, the "muscle protection" effects of PBMT involve reducing inflammation from exercise-induced muscle damage (de Oliveira H. A. et al., 2018) and pre-conditioning the muscle before exercise, thus reducing CK concentration (Ferraresi et al., 2015;Leal-Junior et al., 2015). ...
Article
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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.
... Application of light in vivo before the actual insult or injury occurs has been shown to be protective against muscle damage occurring after exercise in both animals (95,96) and in humans (97,98), cardiac damage occurring after heart attack (99), brain damage occurring after transient cerebral ischemia with bilateral common carotid artery occlusion (100), improved wound healing and protects against scarring after surgery (101), and sunburn occurring after UV exposure (102). ...
... PBM can clearly function as a performance-enhancing intervention in athletic activity and to enhance response to sports training regimens (145,146). This has been shown in individual athletes (for instance an elite runner (97)) and in sports teams such as a volleyball team in a National Championship in Brazil (98). However, since at present, there is no conceivable biochemical assay for having exposed oneself to light, it cannot be outlawed by the World Anti-Doping Agency (WADA). ...
Article
Photobiomodulation (PBM) involves the use of red or near-infrared light at low power densities to produce a beneficial effect on cells or tissues. PBM therapy is used to reduce pain, inflammation, edema, and to regenerate damaged tissues such as wounds, bones and tendons. The primary site of light absorption in mammalian cells has been identified as the mitochondria, and more specifically, cytochrome c oxidase (CCO). It is hypothesized that inhibitory nitric oxide can be dissociated from CCO thus restoring electron transport and increasing mitochondrial membrane potential. Another mechanism involves activation of light or heat-gated ion channels. This review will cover the redox signaling that occurs in PBM and examine the difference between healthy and stressed cells, where PBM can have apparently opposite effects. PBM has a marked effect on stem cells, and this is proposed to operate via mitochondrial redox signaling. PBM can act as a pre-conditioning regimen, and can interact with exercise on muscles.
... In another study, positive results were observed to controlling muscle damage (CK) with irradiation before (40-60 min) a volleyball match in professional players. 35 In this scenario, some authors argue that longer application time would promote a greater window of action of the irradiated light, inducing better results, but even with a shorter time window between application and exercises, other authors obtained significant results in the control of muscle damage. 16,24 Regarding the generation of muscle strength, our study did not observe any variation in the values collected; however, there are studies showing improvements both in the application before 36 and after fatigue. ...
... Regarding the assessment of CK after fatigue induction, a systematic review 38 found nine studies 24,35,[39][40][41][42][43][44][45] that analyzed CK immediately after, one study that evaluated the effects 1 h after, two studies evaluated after 48 h, 16,46 and one study after 72 h. 47 In none of the aforementioned studies, effects were observed after 24 h, similar to the one performed by us. ...
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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).
... Of the 74 articles, 73 % (54/74) did not report methods for light measurement and relied on manufacturers' information. Only 5 % (4/74) of articles reported a full set of data for the parameters/information assessed in this review [83][84][85][86]. For articles that did report light measurement methods, the most common was using a power meter (22 %; 16/74), or equivalent. ...
... For articles that did report light measurement methods, the most common was using a power meter (22 %; 16/74), or equivalent. Remarkably, only six (6/74; 8 %) employed a method that was able to measure spectral properties such as wavelength [39,45,54,67,68,83]. Two articles (3 %; 2/74) failed to report even manufacturers quoted wavelength [48,61]. ...
Article
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Lasers and light-emitting diodes are used for a range of biomedical applications with many studies reporting their beneficial effects. However, three main concerns exist regarding much of the low-level light therapy (LLLT) or photobiomodulation literature; (1) incomplete, inaccurate and unverified irradiation parameters, (2) miscalculation of ‘dose,’ and (3) the misuse of appropriate light property terminology. The aim of this systematic review was to assess where, and to what extent, these inadequacies exist and to provide an overview of ‘best practice’ in light measurement methods and importance of correct light measurement. A review of recent relevant literature was performed in PubMed using the terms LLLT and photobiomodulation (March 2014–March 2015) to investigate the contemporary information available in LLLT and photobiomodulation literature in terms of reporting light properties and irradiation parameters. A total of 74 articles formed the basis of this systematic review. Although most articles reported beneficial effects following LLLT, the majority contained no information in terms of how light was measured (73 %) and relied on manufacturer-stated values. For all papers reviewed, missing information for specific light parameters included wavelength (3 %), light source type (8 %), power (41 %), pulse frequency (52 %), beam area (40 %), irradiance (43 %), exposure time (16 %), radiant energy (74 %) and fluence (16 %). Frequent use of incorrect terminology was also observed within the reviewed literature. A poor understanding of photophysics is evident as a significant number of papers neglected to report or misreported important radiometric data. These errors affect repeatability and reliability of studies shared between scientists, manufacturers and clinicians and could degrade efficacy of patient treatments. Researchers need a physicist or appropriately skilled engineer on the team, and manuscript reviewers should reject papers that do not report beam measurement methods and all ten key parameters: wavelength, power, irradiation time, beam area (at the skin or culture surface; this is not necessarily the same size as the aperture), radiant energy, radiant exposure, pulse parameters, number of treatments, interval between treatments and anatomical location. Inclusion of these parameters will improve the information available to compare and contrast study outcomes and improve repeatability, reliability of studies.
... For the evaluation of the range of mandibular movements, we will follow the guidelines of the International Association for Dental Research for the use of the RDC-TMD, with a single measurement of each movement. [11] The volunteer will be instructed to open his/her mouth as wide as possible for the measurement of maximum voluntary vertical mandibular movement with the aid of digital calipers (distance between maxillary and mandibular central incisors). The volunteer will www.md-journal.com ...
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Background: Orofacial pain encompasses painful conditions, such as temporomandibular disorder (TMD). Multidisciplinary health teams seek to control such musculoskeletal disorders to improve the quality and functional capacity of the muscles of mastication. The aim of the proposed study is to evaluate the effect of low-level laser therapy as a form of treatment for the prevention of initial fatigue of the muscles of mastication (masseter and anterior temporal muscles) as well as the recovery of these muscles after induced exhaustion (caused by isometric contraction) in young adults. Methods: The participants will be 78 healthy male and female volunteers between 18 and 34 years of age. The volunteers will be randomly allocated to a laser group (n = 26), sham group (n = 26), and control group (n = 26). All participants will be submitted to a clinical evaluation to record mandibular movements, bite force, muscle sensitivity to palpation, and initial muscle fatigue. Initial fatigue will be induced by isometric contraction of the jaws. Maximum voluntary contraction will be performed to record the time until initial exhaustion of the masseter muscle (determined by electromyography). The groups will then be submitted to the interventions: active laser therapy (wavelength: 780 nm; fluence: 134 J/cm; power: 50 mW; irradiance: 1.675 W/cm; exposure time: 80 seconds per point) on 3 points of the masseter and 1 point on the anterior temporal muscles on each side; sham laser (placebo effect); or no intervention (control). Maximum voluntary contraction will be performed again after the interventions to record the time until initial exhaustion of the masseter muscle (determined by electromyography). Differences in individual time until exhaustion between the pre- and postintervention evaluations will be measured to determine the effect of low-level laser therapy. Discussion: Although studies have been made with the use of low-level laser therapy in TMDs and on the effect of photobiomodulation on fatigue, this the first study to test this therapy in the prevention of fatigue in this region. The clinical relevance lies in the fact that longer dental procedures could take place if the patients are less prone to fatigue.
... The International Olympic Committee and the World Anti-Doping Agency cannot ban light therapy for athletes considering (1) the intensity is similar to sunlight, and (2) there is no forensic test for light exposure. There have been several clinical trials carried out in Brazil in athletes such as elite runners [94], volleyball players [95] and rugby players [96]. Ferraresi et al conducted a case-controlled study in a pair of identical twins [97]. ...
Article
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Photobiomodulation (PBM) also known as low-level level laser therapy is the use of red and near-infrared light to stimulate healing, relieve pain, and reduce inflammation. The primary chromophores have been identified as cytochrome c oxidase in mitochondria, and calcium ion channels (possibly mediated by light absorption by opsins). Secondary effects of photon absorption include increases in ATP, a brief burst of reactive oxygen species, an increase in nitric oxide, and modulation of calcium levels. Tertiary effects include activation of a wide range of transcription factors leading to improved cell survival, increased proliferation and migration, and new protein synthesis. There is a pronounced biphasic dose response whereby low levels of light have stimulating effects, while high levels of light have inhibitory effects. It has been found that PBM can produce ROS in normal cells, but when used in oxidatively stressed cells or in animal models of disease, ROS levels are lowered. PBM is able to up-regulate anti-oxidant defenses and reduce oxidative stress. It was shown that PBM can activate NF-kB in normal quiescent cells, however in activated inflammatory cells, inflammatory markers were decreased. One of the most reproducible effects of PBM is an overall reduction in inflammation, which is particularly important for disorders of the joints, traumatic injuries, lung disorders, and in the brain. PBM has been shown to reduce markers of M1 phenotype in activated macrophages. Many reports have shown reductions in reactive nitrogen species and prostaglandins in various animal models. PBM can reduce inflammation in the brain, abdominal fat, wounds, lungs, spinal cord.
... The next step in investigating LLLT was in vivo experiments on animals (mostly rats), which showed faster wound healing following LLLT [8,10,12]. The encouraging results of preclinical studies prompted the introduction of LLLT to different fields of medicine (wound healing, rheumatology, oral and sports medicine, etc.) [13][14][15][16]. ...
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Chronic wounds, especially in diabetic patients, represent a challenging health issue. Since standard treatment protocols often do not provide satisfactory results, additional treatment methods—like phototherapy using low-level light therapy—are being investigated. The aim of our study was to evaluate the effect of phototherapy with light-emitting diodes on chronic wound treatment in diabetic and non-diabetic patients. Since a sufficient blood supply is mandatory for wound healing, the evaluation of microcirculation in the healthy skin at a wound’s edge was the main outcome measure. Forty non-diabetic patients and 39 diabetics with lower limb chronic wounds who were referred to the University Medical Center Ljubljana between October 2012 and June 2014 were randomized to the treated and control groups. The treated group received phototherapy with LED 2.4 J/cm² (wavelengths 625, 660, 850 nm) three times a week for 8 weeks, and the control group received phototherapy with broadband 580–900 nm and power density 0.72 J/cm². Microcirculation was measured using laser Doppler. A significant increase in blood flow was noted in the treated group of diabetic and non-diabetic patients (p = 0.040 and p = 0.033), while there was no difference in the control groups. Additional Falanga wound bed score evaluation showed a significant improvement in both treated groups as compared to the control group. According to our results, phototherapy with LED was shown to be an effective additional treatment method for chronic wounds in diabetic and non-diabetic patients.
... In April 2015, an article of Ferraresi et al. [1] was published, which stated that the use of red and near-infrared LEDT was effective in the prevention of muscle damage (CK) in professional volleyball players during official matches. We congratulate the authors for pioneering in investigating Breal world^application of phototherapy in sports and would address some points discussed in our group, some of them against CONSORT statement [2]: ...
... It is very important to highlight the time frame between muscular pre-conditioning and the onset of each exercise protocol used in this study (30 min and 6 h after LEDT) [7,9,37]. Previous in vitro studies have shown that photobiomodulation affects mitochondrial membrane potential and ATP synthesis in hepatocytes using a time frame of 3 min between irradiation and evaluation [6]. ...
Article
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Light-emitting diodes (LEDs) might have a beneficial impact on cytochrome-c oxidase enzyme activity. Thus, it was hypothesized that photobiomodulation by light-emitting diode therapy (LEDT) could influence aerobic metabolism dynamics. Possible LEDT-mediated aerobic improvements were investigated mainly by a precise characterization of the pulmonary O2 uptake dynamics during moderate exercise transitions. Eight healthy young adults were enrolled in this randomized, double-blind, placebo-controlled, crossover study. A multi-diode array of LEDs was used for muscular pre-conditioning 30 min and 6 h before exercise testing. Pulmonary O2 uptake, carbon dioxide output, cardiac output, heart rate, stroke volume, and total arteriovenous oxygen difference dynamics were evaluated by frequency domain analysis. Comparisons revealed no statistical (p > 0.05) differences between LEDT and placebo, suggesting no significant changes in aerobic system dynamics. These results challenge earlier publications that reported changes in pulmonary O2 uptake during incremental exercise until exhaustion after LEDT. Perhaps, increments in peak pulmonary O2 uptake after LEDT may be a consequence of higher exercise tolerance caused by non-aerobic-related factors as opposed to an improved aerobic response.
... There is evidence that lasers in 800-850 nm range may decrease orthodontic pain, TMJ pain and joint pain, at least in the short term [13,14]. NIR LED therapy has shown effects in reducing muscle fatigue [15], healing bone grafts [16,17] and the prevention of sarcopenia [18]. ...
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Background: Numerous strategies have been proposed to decrease orthodontic treatment time. Photobiomodulation (PBM) has previously been demonstrated to assist in this objective. The aim of this study was to test if intraoral PBM increases the rate of tooth alignment and reduces the time required to resolve anterior dental crowding. Methods: Nineteen orthodontic subjects with Class I or Class II malocclusion and Little's Irregularity Index (LII) ≥ 3 mm were selected from a pool of applicants, providing 28 total arches. No cases required extraction. The test group (N = 11, 18 arches, 10 upper, 8 lower) received daily PBM treatment with an intraoral LED device (OrthoPulse™, Biolux Research Ltd.) during orthodontic treatment, while the control group (N = 8, 10 arches, 3 upper, 7 lower) received only orthodontic treatment. The PBM device exposed the buccal side of the gums to near-infrared light with a continuous 850-nm wavelength, generating an average daily energy density of 9.5 J/cm(2). LII was measured at the start (T0) of orthodontic treatment until alignment was reached (T1, where LII ≤ 1 mm). The control group was mostly bonded with 0.018-in slot self-ligating SPEED brackets (Hespeler Orthodontics, Cambridge, ON. Canada), while conventionally-ligating Ormco Mini-Diamond twins were used on the PBM group (Ormco, Glendora, Calif. USA). Both groups progressed through alignment with NiTi arch-wires from 0.014-in through to 0.018-in (Ormco), with identical arch-wire changes. The rate of anterior alignment, in LII mm/week, and total treatment time was collected for both groups. Cox proportional hazards models were used to compare groups and while considering age, sex, ethnicity, arch and degree of crowding. Results: The mean alignment rate for the PBM group was significantly higher than that of the control group, with an LII change rate of 1.27 mm/week (SD 0.53, 95 % CI ± 0.26) versus 0.44 mm/week (SD 0.20, 95 % CI ± 0.12), respectively (p = 0.0002). The treatment time to alignment was significantly smaller for the PBM group, which achieved alignment in 48 days (SD 39, 95 % CI ± 39), while the control group took 104 days (SD 55, 95 % CI ±19, p = 0.0053) on average. These results demonstrated that intraoral PBM increased the average rate of tooth movement by 2.9-fold, resulting in a 54 % average decrease in alignment duration versus control. The average PBM compliance to daily treatments was 93 % during alignment. Conclusions: Under the limitations of this study, the findings suggest that intraoral PBM could be used to decrease anterior alignment treatment time, which could consequently decrease full orthodontic treatment time. However, due to its limitations, further research in the form of a large, randomized trial is needed. Trial registration: ClinicalTrials.gov NCT02267837 . Registered 10 October 2014.
... The next step in investigating LLLT was in vivo experiments on animals (mostly rats), which showed faster wound healing following LLLT [8,10,12]. The encouraging results of preclinical studies prompted the introduction of LLLT to different fields of medicine (wound healing, rheumatology, oral and sports medicine, etc.) [13][14][15][16]. ...
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Objective: The study examined the influence of phototherapy with light-emitting diodes (LEDs) on chronic diabetic wound healing. Background: Chronic diabetic wounds are very difficult to treat due to underlying conditions such as angiopathy and neuropathy, resulting in slow healing rates. Conventional treatment options are often insufficient and do not provide satisfactory outcomes. Phototherapy with LED enhances the healing processes through mechanisms of energy exchange between incoming photons and their target, the main one being cytochrome-c oxidase in mitochondria. Methods: A double-blind, randomized study included 60 patients with a chronic diabetic wound treated at the University Medical Center Ljubljana between October 1, 2012 and December 1, 2014. Patients were randomized into either an active group (LED group) or a control group (Co-group). The active group was treated with LED 2.4 J/cm2 (wavelengths 625, 660, 850 nm) three times a week for 8 weeks. The Co-group was treated with light that simulated LED. Healing was evaluated using the Falanga wound bed score and wound surface area. Results: The average baseline wound surface before treatment was 1315 mm2 in the LED group and 1584 mm2 in the Co-group (p = 0.80). After 8 weeks, the mean surface in the LED group was 56% of the baseline surface and 65% in the Co-group (p > 0.05). Falanga score evaluation showed significantly faster wound bed healing in the LED group compared with the Co-group (p < 0.05). Conclusions: According to our results, LED significantly improves healing of chronic diabetic wounds and prepares the wound bed for further coverage options.
... Some studies involving different muscles of the human body suggest that phototherapy administered before the practice of exercise may reduce fatigue, increase muscle torque, increase endurance, diminish the accumulation of lactate, and improve muscle performance. 1,2,5,12,21,22 In the present study, no statistically significant differences were found with regard to mandibular range of motion. These findings are in agreement with data described in a clinical trial by Muñoz et al., 11 who used laser with wavelengths of 685 and 830 nm, a dose of 30 mW, and energy density of 4 J/cm 2 on eight points of the masseter muscle for 5 sec per point, concluding that the parameters used did not prevent fatigue. ...
Article
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.
... TRPC 1-transient receptor potential canonical channel 1; p-Akt-phosphorylated Akt; p-mTOR-phosphorylated mammalian target of rapamycin; p-FoxO1-phosphorylated Forkhead Box O1; MyoD-myogenic differentiation; MHCslowmyosin heavy chain slow; NF-κB-nuclear factor kappa B; TNF-αtumor necrosis factor alpha; VEGF-vascular endothelial growth factor lactate levels and inhibited the release of Creatine Kinase (CK) and C-Reactive Protein in professional volleyball players [3]. Prevention of significant CK increases was also observed in the blood samples of volleyball players after LEDT (clusters of infrared LEDs 850 ± 20 nm and red LEDs 630 ± 10 nm) [52]. Regarding dystrophic studies, a recent experimental trial, using a cluster probe with nine diodes (one 905 nm laser diode, four 875 nm LED diodes, and four 640 nm LED diodes), showed PBMT beneficial effects on the morphological, biomolecular, and functional aspects in mdx mice [53]. ...
Article
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This study is aimed at investigating the efects of LEDT, at multiple wavelengths, on intracellular calcium concentration; on transient receptor potential canonical channels; on calcium-binding protein; on myogenic factors; on myosin heavy chains; on Akt signaling pathway; on infammatory markers; and on the angiogenic-inducing factor in dystrophic muscle cell culture experimental model. Dystrophic primary muscle cells were submitted to LEDT, at multiple wavelengths (420 nm, 470 nm, 660 nm, and 850 nm), and evaluated after 48 h for cytotoxic efects and intracellular calcium content. TRPC-1, TRPC-6, Calsequestrin, MyoD, Myogenin, MHC-slow, MHC-fast, p-AKT, p-mTOR, p-FoxO1, Myostatin, NF-κB, TNF-α, and VEGF levels were evaluated in dystrophic primary muscle cells by western blotting. The LEDT, at multiple wavelengths, treatedmdx muscle cells showed no cytotoxic efect and signifcant lower levels in [Ca2+]i. The mdx muscle cells treated with LEDT showed a signifcant reduction of TRPC-1, NF-κB, TNF-α and MyoD levels and a signifcant increase of Myogenin, MHCslow, p-AKT, p-mTOR, p-FoxO1 levels, and VEGF levels. Our fndings suggest that diferent LEDT wavelengths modulate the Akt-signaling pathways and attenuate pathological events in dystrophic muscle cells, and a combined multiwavelength irradiation protocol may even provide a potentially therapeutic strategy for muscular dystrophies.
... In a study conducted by Ferraresi et al. [24], results showing the effectiveness of preventative phototherapy in male volleyball athletes in real competition situations were found to inhibit the expected increase of CK enzyme activity in the bloodstream 24 h after the match. This study used four different doses, and one of them was a placebo. ...
Article
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This study aimed to analyze PBMT effects on futsal player’s performance and recovery in a non-controlled field environment. It is a randomized, triple-blinded, placebo-controlled, crossover clinical trial. The research included six professional athletes and in each match phototherapy treatments were performed before matches (40 minutes), blood samples were collected before treatments, and samples immediately after the end of the matches and 48 h after. Furthermore, videos were analyzed to quantify the time athletes spent on the pitch and the distance they covered. PBMT was performed at 17 sites of each lower limb (40 mins before matches), employing a cluster with 12 diodes (4 laser diodes of 905 nm, 4 LEDs of 875 nm, and 4 LEDs of 640 nm, 30 J per site). The performance of the athlete could be quantified considering the time on the pitch and the distance covered; the biochemical markers evaluated were creatine kinase, lactate dehydrogenase, blood lactate, and oxidative damage to lipids and proteins. PBMT significantly increased the time of staying in the pitch and a significant improvement in all the biochemical markers evaluated. No statistically significant difference was found for the distance covered. Pre-exercise PBMT can enhance performance and accelerate recovery of high-level futsal players.
... TRPC 1-transient receptor potential canonical channel 1; p-Akt-phosphorylated Akt; p-mTOR-phosphorylated mammalian target of rapamycin; p-FoxO1-phosphorylated Forkhead Box O1; MyoD-myogenic differentiation; MHCslowmyosin heavy chain slow; NF-κB-nuclear factor kappa B; TNF-αtumor necrosis factor alpha; VEGF-vascular endothelial growth factor lactate levels and inhibited the release of Creatine Kinase (CK) and C-Reactive Protein in professional volleyball players [3]. Prevention of significant CK increases was also observed in the blood samples of volleyball players after LEDT (clusters of infrared LEDs 850 ± 20 nm and red LEDs 630 ± 10 nm) [52]. Regarding dystrophic studies, a recent experimental trial, using a cluster probe with nine diodes (one 905 nm laser diode, four 875 nm LED diodes, and four 640 nm LED diodes), showed PBMT beneficial effects on the morphological, biomolecular, and functional aspects in mdx mice [53]. ...
... Then, the enzyme cytochrome C oxidase is activated, which stimulates the production of ATP in the mitochondrial respiratory chain and thus will stimulate fiber maturation and muscle repair through increased synthesis of myoregulatory factors such as myogenin and MRF4 [52,53]. As already shown in the study published by de Oliveira et al. [14], PBM can induce muscle protection in athletes through the action of reducing inflammation and CK levels [54] produced during physical activity. ...
Article
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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.
... TRPC 1-transient receptor potential canonical channel 1; p-Akt-phosphorylated Akt; p-mTOR-phosphorylated mammalian target of rapamycin; p-FoxO1-phosphorylated Forkhead Box O1; MyoD-myogenic differentiation; MHCslowmyosin heavy chain slow; NF-κB-nuclear factor kappa B; TNF-αtumor necrosis factor alpha; VEGF-vascular endothelial growth factor lactate levels and inhibited the release of Creatine Kinase (CK) and C-Reactive Protein in professional volleyball players [3]. Prevention of significant CK increases was also observed in the blood samples of volleyball players after LEDT (clusters of infrared LEDs 850 ± 20 nm and red LEDs 630 ± 10 nm) [52]. Regarding dystrophic studies, a recent experimental trial, using a cluster probe with nine diodes (one 905 nm laser diode, four 875 nm LED diodes, and four 640 nm LED diodes), showed PBMT beneficial effects on the morphological, biomolecular, and functional aspects in mdx mice [53]. ...
... TRPC 1-transient receptor potential canonical channel 1; p-Akt-phosphorylated Akt; p-mTOR-phosphorylated mammalian target of rapamycin; p-FoxO1-phosphorylated Forkhead Box O1; MyoD-myogenic differentiation; MHCslowmyosin heavy chain slow; NF-κB-nuclear factor kappa B; TNF-αtumor necrosis factor alpha; VEGF-vascular endothelial growth factor lactate levels and inhibited the release of Creatine Kinase (CK) and C-Reactive Protein in professional volleyball players [3]. Prevention of significant CK increases was also observed in the blood samples of volleyball players after LEDT (clusters of infrared LEDs 850 ± 20 nm and red LEDs 630 ± 10 nm) [52]. Regarding dystrophic studies, a recent experimental trial, using a cluster probe with nine diodes (one 905 nm laser diode, four 875 nm LED diodes, and four 640 nm LED diodes), showed PBMT beneficial effects on the morphological, biomolecular, and functional aspects in mdx mice [53]. ...
Article
This study is aimed at investigating the efects of LEDT, at multiple wavelengths, on intracellular calcium concentration; on transient receptor potential canonical channels; on calcium-binding protein; on myogenic factors; on myosin heavy chains; on Akt signaling pathway; on infammatory markers; and on the angiogenic-inducing factor in dystrophic muscle cell culture experimental model. Dystrophic primary muscle cells were submitted to LEDT, at multiple wavelengths (420 nm, 470 nm, 660 nm, and 850 nm), and evaluated after 48 h for cytotoxic efects and intracellular calcium content. TRPC-1, TRPC-6, Calsequestrin, MyoD, Myogenin, MHC-slow, MHC-fast, p-AKT, p-mTOR, p-FoxO1, Myostatin, NF-κB, TNF-α, and VEGF levels were evaluated in dystrophic primary muscle cells by western blotting. The LEDT, at multiple wavelengths, treatedmdx muscle cells showed no cytotoxic efect and signifcant lower levels in [Ca2+]i. The mdx muscle cells treated with LEDT showed a signifcant reduction of TRPC-1, NF-κB, TNF-α and MyoD levels and a signifcant increase of Myogenin, MHCslow, p-AKT, p-mTOR, p-FoxO1 levels, and VEGF levels. Our fndings suggest that diferent LEDT wavelengths modulate the Akt-signaling pathways and attenuate pathological events in dystrophic muscle cells, and a combined multiwavelength irradiation protocol may even provide a potentially therapeutic strategy for muscular dystrophies.
... TRPC 1-transient receptor potential canonical channel 1; p-Akt-phosphorylated Akt; p-mTOR-phosphorylated mammalian target of rapamycin; p-FoxO1-phosphorylated Forkhead Box O1; MyoD-myogenic differentiation; MHCslowmyosin heavy chain slow; NF-κB-nuclear factor kappa B; TNF-αtumor necrosis factor alpha; VEGF-vascular endothelial growth factor lactate levels and inhibited the release of Creatine Kinase (CK) and C-Reactive Protein in professional volleyball players [3]. Prevention of significant CK increases was also observed in the blood samples of volleyball players after LEDT (clusters of infrared LEDs 850 ± 20 nm and red LEDs 630 ± 10 nm) [52]. Regarding dystrophic studies, a recent experimental trial, using a cluster probe with nine diodes (one 905 nm laser diode, four 875 nm LED diodes, and four 640 nm LED diodes), showed PBMT beneficial effects on the morphological, biomolecular, and functional aspects in mdx mice [53]. ...
Article
This study is aimed at investigating the effects of LEDT, at multiple wavelengths, on intracellular calcium concentration; on transient receptor potential canonical channels; on calcium-binding protein; on myogenic factors; on myosin heavy chains; on Akt signaling pathway; on inflammatory markers; and on the angiogenic-inducing factor in dystrophic muscle cell culture experimental model. Dystrophic primary muscle cells were submitted to LEDT, at multiple wavelengths (420 nm, 470 nm, 660 nm, and 850 nm), and evaluated after 48 h for cytotoxic effects and intracellular calcium content. TRPC-1, TRPC-6, Calsequestrin, MyoD, Myogenin, MHC-slow, MHC-fast, p-AKT, p-mTOR, p-FoxO1, Myostatin, NF-κB, TNF-α, and VEGF levels were evaluated in dystrophic primary muscle cells by western blotting. The LEDT, at multiple wavelengths, treated-mdx muscle cells showed no cytotoxic effect and significant lower levels in [Ca2 +]i. The mdx muscle cells treated with LEDT showed a significant reduction of TRPC-1, NF-κB, TNF-α and MyoD levels and a significant increase of Myogenin, MHC-slow, p-AKT, p-mTOR, p-FoxO1 levels, and VEGF levels. Our findings suggest that different LEDT wavelengths modulate the Akt-signaling pathways and attenuate pathological events in dystrophic muscle cells, and a combined multiwavelength irradiation protocol may even provide a potentially therapeutic strategy for muscular dystrophies.
... The biomodulatory effect of LBP can be observed mainly in the inflammatory phase. Some authors have demonstrated that laser therapy is able to decrease the number of inflammatory cells, increase angiogenesis, stimulate the differentiation of myofibroblasts, increase the proliferation of epithelial cells and collagen synthesis, contributing to better healing of skin lesions [10][11][12][13]. Among those involved in photobiomodulation by LBP, light is able to promote action on prostaglandins (PG) by changing intracapillary hydrostatic pressure and increasing the absorption of interstitial fluids, decreasing edema [14,15]. ...
Article
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Aim study was to evaluate the effects of low-power laser photobiomodulation (LBP) in third-degree burns induced in an animal model. Forty Wistar rats (Ratus norvegicus albinus) were used, females weighing between 200 and 300 grams, randomly divided into a control group (GC = 20) and a laser-treated group (DL = 20). A 1cm² third-degree burn injury was performed on the back of each animal after trichotomy and followed by surgical debridement 24 hours after induction. In the treated group (LBP) a laser was applied at a wavelength of 660 nm, a power of 27 mW and an average irradiance of 0.954 W / cm2 at five points of the wound. The total fluency was 350 Joules / cm2 and application of 5 Joules per wound. Biopsy fragments were collected on days 3, 7, 15 and 21 post-injury for macro and microscopic analysis using the techniques of Hematoxylin and Eosin (HE), Gomori's Trichrome (TG) and Picrosirius red. The results were evaluated by Tukey's Test and Analysis of Variance (ANOVA), Kruskal-Wallis Test (non-parametric) and T-paired Test. The healing process evaluated by morphometry showed a relative statistical difference between the CG and LBP groups. Histopathological analysis showed a decrease in the inflammatory infiltrate, angiogenesis, synthesis of granulation tissue and collagen deposition, increased fibroblasts, matrix organization, and reepithelization of the lesion. Thus, low-power laser photobiomodulation can contribute to the wound repair process efficiently.
... Light-emitting diode therapy is an increasingly popular methodology. Light-emitting diode has improved short-term postexercise recovery in volleyball athletes [80], to determine the effects of light-emitting diode therapy on blood lactate concentration clearance, peak power output and fatigue index after intense exercise. Further research using different parameters is required to determine how light-emitting diode therapy may contribute to post-exercise recovery [81]. ...
Article
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In the sport of rugby, athletes need a multitude of sport-specific skills along with endurance, power, and speed in order to optimize performance. Further, it is not unusual for athletes to play several competitive matches with insufficient recovery time. Rugby requires repeated bouts of high-intensity actions intermixed with brief periods of low to moderate active recovery or passive rest. Specifically, a match is characterized by repeated explosive activities, such as: jumps, shuffles, and rapid changes of direction. To facilitate adequate recovery, it is necessary to understand the type of fatigue induced and, if possible, its underlying mechanisms. Common approaches to recovery may include nutritional strategies as well as active (active recovery) and passive recovery (water immersions, stretching, and massage) methods. However, limited research exists to support the effectiveness of each strategy as it related to recovery from the sport of rugby. Therefore, the main aim of the current brief review is to present the relevant literature that pertains to recovery strategies in rugby.
... Therefore, several research groups around the world, are assessing the efficacy of these light sources in in vitro and in vivo experimental designs, in order to correlate the efficacy levels of this technology with the established LILT to obtain safe and efficient irradiation protocols for the management of chronic pain in the orofacial region. Numerous clinical studies published in the current literature have proved the efficacy of the light radiation emitted by LEDs (LED-therapy) [3][4][5][6][7][8][9] in the drainage of lymph nodes and as potent antiinflammatory agent in the prevention of degenerative processes of athletes' muscles and joints. The use of LED sources has been demonstrating high levels of clinical success. ...
Article
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Considering several clinical situations, low intensity laser therapy has been widely applied in pain relief or analgesia mechanism. With the advent of new LED-based (light emitting diode) light sources, the need of further clinical experiments aiming to compare the effectiveness among them is paramount. The LED system therapeutic use can be denominated as LEDT-Light Emitting Diode Therapy. This study proposed two clinical evaluations of pain relief effect: to dentin hypersensitivity and to cervicogenic headache using different sources of lasers (low and high intensity) and light emitting diodes (LEDs), one emitting at the spectral band of red (630+/-5nm) and the other one at infrared band (880+/-5nm). Two different clinical studies were performed and presented interesting results. Considering dentin hypersensitivity, red and infrared led were so effective than the control group (high intensity laser system); by the other side, considering cervicogenic headache, control group (infrared laser) was the best treatment in comparison to red and infrared led system.
... Ferraresi et al. found that pre-treatment of muscles with red and near-infrared LED can effectively prevent muscle damage in professional volleyball players in competitions [10]. Fan et al. discovered the PBM could activate hair follicle stem cells via the ipRGC-SCN-sympathetic pathway [11]. ...
Article
Photobiomodulation (PBM) that uses low‐intensity visible or near‐infrared light to produce beneficial effects on cells or tissues, such as brain therapy, wound healing. Still there is no consistent recommendation on the parameters (dose, light mode, wavelength, irradiance) and protocols (repetition, treatment duration) for its clinical application. Herein, we summarize the current PBM parameters for the treatment of melanoma, and we also discuss the potential photoreceptors and downstream signaling mechanisms in the PBM treatment of melanoma cells. It is hypothesized that PBM may inhibit the melanoma cells by activating mitochondria, OPNs, and other receptors. Regardless of the underlying mechanisms, PBM has been shown to be beneficial in treating melanoma. Through further in‐depth studies of the underlying potential mechanisms, it can strengthen the applications of PBM for the therapy of melanoma.
... In a recent systematic review and meta-analysis, Leal-Junior et al. (20) analyzed 13 articles and concluded that PBMT with LLLT and LEDT is more beneficial when administered prior to physical activity, as it preserves the muscle tissue and accelerates post-exercise recovery time. Ferraresi et al. (21) investigated the effects of PBMT with LEDT on the prevention of muscle damage through an analysis of CK in professional volleyball players. The authors tested four different energy doses on four groups of athletes (one of which was sham therapy) and found positive effects when the total energy per muscle group was 210 and 315 J (exposure time of 40 and 60s, respectively). ...
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Background: Photobiomodulation with low-level laser therapy (LLLT) has been widely used in clinical practice for diverse purposes, such as modulation of the inflammatory process, acceleration of the tissue repair process, pain relief and the enhancement of post-exercise recovery. Studies have demonstrated a beneficial interaction between photobiomodulation and the production of creatine kinase, with a reduction in the release of this marker of muscle damage when laser and/or LEDs is administered prior to high-intensity physical activity. Objective: The aim of the proposed study is to determine the influence of pre-exercise phototherapy on post-exercise muscle recovery. Methods: A randomized, cross-over, sham-controlled, double-blind, clinical trial is proposed. The participants will be healthy professional soccer players aged 15 to 20 years from the same team with a body mass index within the ideal range (20 to 25 kg/m2 ) and no history of lower limb musculoskeletal injuries or surgery or back surgery in the previous six months. The athletes will be allocated to two groups based on the previously calculated sample size and will be blinded to allocation. Creatine kinase will be measured and the subjective perception of fatigue will be determined for each participant. The volunteers will then be randomly allocated to Group A, which will receive active phototherapy, and Group B, which will receive sham phototherapy. The athletes will undergo reevaluations immediately after as well as 48 hours after a football match. The data will be submitted to statistical analysis and the level of significance will be set to 5%. This study is registered with Clinical Trials under protocol number: NCT03416998.
... Between the participants of the LED group until the end of the 5th session, there was a reduction of 47.60% of the wound compared to 42.86% in the injuries treated with laser. With the hypothesis, the possibility of the wavelength and dispersion of the LED light were more significant compared to that of the laser [26]. However, with inaccuracies about the differences in the mechanisms of action between the laser and the LED, a greater understanding about the absorption of light should be considered, so that there is a better justification of these findings. ...
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To compare the influence of laser and LED on tissue repair and neuropathic symptoms during treatment of diabetic foot. An intervention survey conducted in a health center located in Brazil, contemplating ten sessions, twice a week, with randomization in two groups. In one group, the wounds were treated with GaAlAs laser, with a wavelength of 830 nm, 30 mW, and power density 0.84 W/cm², the other group by LED 850 nm, 48 mW, and power density 1.05 W/cm². For the analysis of wound size, photographic records analyzed by the ImageJ® software were used, and the neuropathy evaluation card examined. With regard to the laser group, a reduction in wound extension of 79.43% was observed at the end of the 10th session; the patients in the LED group had a 55.84% decrease in the healing process; comparing the two therapies was observed a better healing in the participants of the laser group, with 81.17%, in relation to the LED after the end of the sessions; regarding the evaluation of the neuropathic condition, there was a significant improvement in both therapies. There was improvement of the neuropathic signs and symptoms, also improvement of the tissue repair in the two therapeutic modalities; however, the laser presented a higher rate of speed in relation to the LED.
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Recently, phototherapies, such as low reactive level laser therapy (LLLT) and light emitting diode therapy, have been referred to as photobiomodulation therapies (PBMT). It has been reported that PBMT is effective not only in the treatment and prevention of sports-related disorders but also in improving the performance of athletes by delaying muscle fatigue. This study summarizes previous published reports that examined PBMT-induced performance improvement effects in athletes of different sport types.
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Photobiomodulation (PBM) describes the use of red or near-infrared (NIR) light to stimulate, heal, and regenerate damaged tissue. Both preconditioning (light delivered to muscles before exercise) and PBM applied after exercise can increase sports performance in athletes. This review covers the effects of PBM on human muscle tissue in clinical trials in volunteers related to sports performance and in athletes. The parameters used were categorized into those with positive effects or no effects on muscle performance and recovery. Randomized controlled trials and case-control studies in both healthy trained and untrained participants, and elite athletes were retrieved from MEDLINE up to 2016. Performance metrics included fatigue, number of repetitions, torque, hypertrophy; measures of muscle damage and recovery such as creatine kinase and delayed onset muscle soreness. Searches retrieved 533 studies, of which 46 were included in the review (n = 1045 participants). Studies used single laser probes, cluster of laser diodes, LED clusters, mixed clusters (lasers and LEDs), and flexible LED arrays. Both red, NIR, and red/NIR mixtures were used. PBM can increase muscle mass gained after training, and decrease inflammation and oxidative stress in muscle biopsies. We raise the question of whether PBM should be permitted in athletic competition by international regulatory authorities.
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The aim of this study was to evaluate the effectiveness of pre-exercise low-level phototherapy (Light-Emitting Diode therapy [LEDtherapy] or Light Amplification by Stimulate Emission of Radiation therapy [LASERtherapy]) in increasing exercise capacity and muscle performance of people undergoing exercise when compared to placebo treatment. Randomized controlled trials and crossover studies were sought on CENTRAL, MEDLINE, EMBASE, SciELO, PEDro and LILACS from its inception up to February 2015. References lists of included studies were sought for additional relevant research. Two authors independently extracted data on study design, treatment parameters, exercise capacity (number of repetitions, time to exhaustion, blood lactate concentration and lactate dehydrogenase activity) and muscle performance (torque, power and strength) using an structured table. Agreement should be reached by consensus or by a third reviewer. Sixteen studies involving 297 participants were included. Improvement of number of repetitions (mean difference [MD] [95 % confidence interval] = 3.51 repetitions [0.65–6.37]; P = 0.02), delay in time to exhaustion (MD = 4.01 s [2.10–5.91]; P < 0.0001), reduction in lactate levels (MD = 0.34 mmol/L [0.19–0.48]; P < 0.00001) and increased peak torque (MD = 21.51 Nm [10.01–33.01]; P < 0.00001) were observed when LASERtherapy was applied. LEDtherapy meta-analyses were performed with two studies and retrieved no between-group statistically significant difference in power, lactate levels or time to exhaustion. Although our results suggest that LASERtherapy is effective in improving skeletal muscle exercise capacity, the quality of the current evidence is limited.
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Objective: The aim of this study was to verify how a pair of monozygotic twins would respond to light-emitting diode therapy (LEDT) or placebo combined with a strength-training program during 12 weeks. Design: This case-control study enrolled a pair of male monozygotic twins, allocated randomly to LEDT or placebo therapies. Light-emitting diode therapy or placebo was applied from a flexible light-emitting diode array (λ = 850 nm, total energy = 75 J, t = 15 seconds) to both quadriceps femoris muscles of each twin immediately after each strength training session (3 times/wk for 12 weeks) consisting of leg press and leg extension exercises with load of 80% and 50% of the 1-repetition maximum test, respectively. Muscle biopsies, magnetic resonance imaging, maximal load, and fatigue resistance tests were conducted before and after the training program to assess gene expression, muscle hypertrophy and performance, respectively. Creatine kinase levels in blood and visual analog scale assessed muscle damage and delayed-onset muscle soreness, respectively, during the training program. Results: Compared with placebo, LEDT increased the maximal load in exercise and reduced fatigue, creatine kinase, and visual analog scale. Gene expression analyses showed decreases in markers of inflammation (interleukin 1β) and muscle atrophy (myostatin) with LEDT. Protein synthesis (mammalian target of rapamycin) and oxidative stress defense (SOD2 [mitochondrial superoxide dismutase]) were up-regulated with LEDT, together with increases in thigh muscle hypertrophy. Conclusions: Light-emitting diode therapy can be useful to reduce muscle damage, pain, and atrophy, as well as to increase muscle mass, recovery, and athletic performance in rehabilitation programs and sports medicine.
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INTRODUCTION: In current team sports (including volleyball), the players have to play numerous competitive matches without time to recover. Volleyball can be defined as a moderate duration exercise including repeated bouts of high-intensity activity interspersed with brief periods of low to moderate active recovery or passive rest. A match is characterized by repeated explosive activities, such as: jumps, shuffles and rapid changes in direction. EVIDENCE ACQUISITION: To guarantee adequate recovery after matches, it is necessary to know the type of fatigue induced and if possible its underlying mechanisms. Recovery strategies are commonly utilized in volleyball despite limited scientific confirmation to support their effectiveness to facilitating optimal recovery. EVIDENCE SYNTHESIS: It is particularly important to optimize recovery because players spend a much greater proportion of their time recovering than they do in training. CONCLUSIONS: Therefore, the main aim of this brief review is to facilitate useful information for practical application, based on the scientific evidence and applied knowledge specifically in volleyball
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Recently, low-level laser (light) therapy (LLLT) has been used to improve muscle performance. This study aimed to evaluate the effectiveness of near-infrared light-emitting diode therapy (LEDT) and its mechanisms of action to improve muscle performance in an elite athlete. The kinetics of oxygen uptake (VO2), blood and urine markers of muscle damage (creatine kinase – CK and alanine) and fatigue (lactate) were analyzed. Additionally, some metabolic parameters were assessed in urine using proton nuclear magnetic resonance spectroscopy (1H NMR). A LED cluster with 50 LEDs (�¼850 nm; 50mW 15 s; 37.5 J) was applied on legs, arms and trunk muscles of a single runner athlete 5 min before a high-intense constant workload running exercise on treadmill. The athlete received either Placebo-1-LEDT; Placebo-2-LEDT; or Effective-LEDT in a randomized double-blind placebo-controlled trial with washout period of 7 d between each test. LEDT improved the speed of the muscular VO2 adaptation (~-9 s), decreased O2 deficit (~-10 L), increased the VO2 from the slow component phase (~+348 mlmin�1) and increased the time limit of exercise (~+589 s). LEDT decreased blood and urine markers of muscle damage and fatigue (CK, alanine and lactate levels). The results suggest that a muscular pre-conditioning regimen using LEDT before intense exercises could modulate metabolic and renal function to achieve better performance.
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Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905 nm lasers-0.3125 mW each, 4 of 875 nm LEDs-17.5 mW each, and 4 of 670 nm LEDs-15 mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50 J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1 min, 1, 24, 48, 72, and 96 h after eccentric exercise protocol employed to induce fatigue. Phototherapy increased (p < 0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose). DOMS was significantly decreased compared to placebo (p < 0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise. CK activity was significantly decreased (p < 0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.
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This study aimed to evaluate the effects of low-level laser therapy (LLLT) immediately before tetanic contractions in skeletal muscle fatigue development and possible tissue damage. Male Wistar rats were divided into two control groups and nine active LLLT groups receiving one of three different laser doses (1, 3, and 10 J) with three different wavelengths (660, 830, and 905 nm) before six tetanic contractions induced by electrical stimulation. Skeletal muscle fatigue development was defined by the percentage (%) of the initial force of each contraction and time until 50 % decay of initial force, while total work was calculated for all six contractions combined. Blood and muscle samples were taken immediately after the sixth contraction. Several LLLT doses showed some positive effects on peak force and time to decay for one or more contractions, but in terms of total work, only 3 J/660 nm and 1 J/905 nm wavelengths prevented significantly (p < 0.05) the development of skeletal muscle fatigue. All doses with wavelengths of 905 nm but only the dose of 1 J with 660 nm wavelength decreased creatine kinase (CK) activity (p < 0.05). Qualitative assessment of morphology revealed lesser tissue damage in most LLLT-treated groups, with doses of 1-3 J/660 nm and 1, 3, and 10 J/905 nm providing the best results. Optimal doses of LLLT significantly delayed the development skeletal muscle performance and protected skeletal muscle tissue against damage. Our findings also demonstrate that optimal doses are partly wavelength specific and, consequently, must be differentiated to obtain optimal effects on development of skeletal muscle fatigue and tissue preservation. Our findings also lead us to think that the combined use of wavelengths at the same time can represent a therapeutic advantage in clinical settings.
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Objectives: The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) before and after exercise on quadriceps muscle performance, and to evaluate the changes in serum lactate and creatine kinase (CK) levels. Methods: The study was randomized, double blind, and placebo controlled. Patients: A sample of 27 healthy volunteers (male soccer players) were divided into three groups: placebo, pre-fatigue laser, and post-fatigue laser. The experiment was performed in two sessions, with a 1 week interval between them. Subjects performed two sessions of stretching followed by blood collection (measurement of lactate and CK) at baseline and after fatigue of the quadriceps by leg extension. LLLT was applied to the femoral quadriceps muscle using an infrared laser device (830 nm), 0.0028 cm(2) beam area, six 60 mW diodes, energy of 0.6 J per diode (total energy to each limb 25.2 J (50.4 J total), energy density 214.28 J/cm(2), 21.42 W/cm(2) power density, 70 sec per leg. We measured the time to fatigue and number and maximum load (RM) of repetitions tolerated. Number of repetitions and time until fatigue were primary outcomes, secondary outcomes included serum lactate levels (measured before and 5, 10, and 15 min after exercise), and CK levels (measured before and 5 min after exercise). Results: The number of repetitions (p=0.8965), RM (p=0.9915), and duration of fatigue (p=0.8424) were similar among the groups. Post-fatigue laser treatment significantly decreased the serum lactate concentration relative to placebo treatment (p<0.01) and also within the group over time (after 5 min vs. after 10 and 15 min, p<0.05 both). The CK level was lower in the post-fatigue laser group (p<0.01). Conclusions: Laser application either before or after fatigue reduced the post-fatigue concentrations of serum lactate and CK. The results were more pronounced in the post-fatigue laser group.
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Recent studies have explored if phototherapy with low-level laser therapy (LLLT) or narrow-band light-emitting diode therapy (LEDT) can modulate activity-induced skeletal muscle fatigue or subsequently protect against muscle injury. We performed a systematic review with meta-analysis to investigate the effects of phototherapy applied before, during and after exercises. A literature search was performed in Pubmed/Medline database for randomized controlled trials (RCTs) published from 2000 through 2012. Trial quality was assessed with the ten-item PEDro scale. Main outcome measures were selected as: number of repetitions and time until exhaustion for muscle performance, and creatine kinase (CK) activity to evaluate risk for exercise-induced muscle damage. The literature search resulted in 16 RCTs, and three articles were excluded due to poor quality assessment scores. From 13 RCTs with acceptable methodological quality (≥6 of 10 items), 12 RCTs irradiated phototherapy before exercise, and 10 RCTs reported significant improvement for the main outcome measures related to performance. The time until exhaustion increased significantly compared to placebo by 4.12 s (95 % CI 1.21-7.02, p < 0.005) and the number of repetitions increased by 5.47 (95 % CI 2.35-8.59, p < 0.0006) after phototherapy. Heterogeneity in trial design and results precluded meta-analyses for biochemical markers, but a quantitative analysis showed positive results in 13 out of 16 comparisons. The most significant and consistent results were found with red or infrared wavelengths and phototherapy application before exercises, power outputs between 50 and 200 mW and doses of 5 and 6 J per point (spot). We conclude that phototherapy (with lasers and LEDs) improves muscular performance and accelerate recovery mainly when applied before exercise.
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The aim of this randomized double-blind placebo-controlled study was to investigate the effect of low-level laser therapy (LLLT) on markers of muscle damage (creatine kinase (CK) and strength performance) in the biceps brachii. Twenty-two physically active men were randomized into two groups: placebo and laser. All volunteers were submitted to an exercise-induced muscle damage protocol for biceps brachii (biceps curl, 10 sets of 10 repetitions with load of 50 % of one-repetition maximum test (1RM)). Active LLLT (808 nm; 100 mW; 35.7 W/cm(2), 357.14 J/cm(2) per point, energy of 1 J per point applied for 10 s on four points of the biceps brachii belly of each arm) or placebo was applied between the sets of the biceps curl exercise. CK activity and maximum strength performance (1RM) were measured before, immediately after, 24, 48, and 72 h after the exercise-induced muscle damage protocol. There was an increase in CK activity after the muscle damage protocol in both groups; however, this increase was attenuated in the laser group compared to the placebo group at 72 h (placebo = 841 vs. laser = 357 %; p < 0.05). Maximum strength performance was decreased immediately after the muscle damage protocol in both groups (p < 0.05), but at 24, 48, and 72 h, and it returned to the baseline level in both groups. In conclusion, the LLLT attenuated CK activity 72 h after the muscle damage protocol but did not have a positive effect on the recovery of strength performance.
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The aim of this study was to test, between two bouts of exercise, the effects of light-emitting diode (LED) therapy and cryotherapy regarding muscle damage, inflammation and performance. Male Wistar rats were allocated in 4 groups: control (Co), passive recovery (PR), cryotherapy (Cryo) and LED therapy. The animals were submitted to 45 min of swimming exercise followed by 25 min of recovery and then a second bout of either 45 min of exercise (muscle damage analysis) or time-to-exhaustion (performance). During the rest intervals, the rats were kept in passive rest (PR), submitted to cold-water immersion (10 min, 10°C) or LED therapy (940nm, 4J/cm2) of the gastrocnemius muscle. Blood samples were collected to analyze creatine kinase activity (CK), C reactive protein (CRP) and leukocyte counts. The soleus muscles were evaluated histologically. Time-to-exhaustion was recorded during the second bout of exercise. After a second bout of 45 min, the results demonstrated leukocytosis in PR and Cryo groups. Neutrophil counts were increased in all test groups. CK levels were increased in Cryo group. CRP was increased in PR animals. The PR group presented a high frequency of necrosis, but the LED group had fewer necrotic areas. Edema formation was prevented and fewer areas of inflammatory cells were observed in the LED group. The time to exhaustion was greater in both the LED and Cryo groups, without differences in CK levels. CRP was decreased in LED animals. We conclude that LED therapy and Cryotherapy can improve performance, although LED therapy is more efficient in preventing muscle damage and local and systemic inflammation. Powered by Editorial Manager® and Preprint Manager® from Aries Systems Corporation
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The use of low level laser (light) therapy (LLLT) has recently expanded to cover areas of medicine that were not previously thought of as the usual applications such as wound healing and inflammatory orthopedic conditions. One of these novel application areas is LLLT for muscle fatigue and muscle injury. Since it is becoming agreed that mitochondria are the principal photoacceptors present inside cells, and it is known that muscle cells are exceptionally rich in mitochondria, this suggests that LLLT should be highly beneficial in muscle injuries. The ability of LLLT to stimulate stem cells and progenitor cells means that muscle satellite cells may respond well to LLLT and help muscle repair. Furthermore the ability of LLLT to reduce inflammation and lessen oxidative stress is also beneficial in cases of muscle fatigue and injury. This review covers the literature relating to LLLT and muscles in both preclinical animal experiments and human clinical studies. Athletes, people with injured muscles, and patients with Duchenne muscular dystrophy may all benefit.
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Studies suggest that high-intensity physical exercise can cause damage to skeletal muscles, resulting in muscle soreness, fatigue, inflammatory processes and cell apoptosis. The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on a decrease in creatine kinase (CK) levels and cell apoptosis. Twenty male Wistar rats were randomly divided into two equal groups: group 1 (control), resistance swimming; group 2 (LLLT), resistance swimming with LLLT. They were subjected to a single application of indium gallium aluminum phosphide (InGaAlP) laser immediately following the exercise for 40s at an output power of 100mW, wavelength 660nm and 133.3J/cm2. The groups were subdivided according to sample collection time: 24h and 48h. CK was measured before and both 24h and 48h after the test. Samples of the gastrocnemius muscle were processed to determine the presence of apoptosis using terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labeling. (There was a significant difference in CK levels between groups (P < 0.0001) as well as between the 24h and 48h levels in the control group, whereas there was no significant intra-group difference in the LLLT group at the same evaluation times. In the LLLT group there were 66.3 ± 13.2 apoptotic cells after 24h and 39.0 ± 6.8 apoptotic cells after 48h. The results suggest that LLLT influences the metabolic profile of animals subjected to fatigue by lowering serum levels of CK. This demonstrates that LLLT can act as a preventive tool against cell apoptosis experienced during high-intensity physical exercise.
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Our aim was to investigate the immediate effects of bilateral, 830nm, low-level laser therapy (LLLT) on high-intensity exercise and biochemical markers of skeletal muscle recovery, in a randomised, double-blind, placebo-controlled, crossover trial set in a sports physiotherapy clinic. Twenty male athletes (nine professional volleyball players and eleven adolescent soccer players) participated. Active LLLT (830nm wavelength, 100mW, spot size 0.0028cm2, 3–4 J per point) or an identical placebo LLLT was delivered to five points in the rectus femoris muscle (bilaterally). The main outcome measures were the work performed in the Wingate test: 30s of maximum cycling with a load of 7.5% of body weight, and the measurement of blood lactate (BL) and creatine kinase (CK) levels before and after exercise. There was no significant difference in the work performed during the Wingate test (P > 0.05) between subjects given active LLLT and those given placebo LLLT. For volleyball athletes, the change in CK levels from before to after the exercise test was significantly lower (P = 0.0133) for those given active LLLT (2.52Ul−1 ± 7.04Ul−1) than for those given placebo LLLT (28.49Ul−1 ± 22.62Ul−1). For the soccer athletes, the change in blood lactate levels from before exercise to 15min after exercise was significantly lower (P < 0.01) in the group subjected to active LLLT (8.55mmoll−1 ± 2.14mmoll−1) than in the group subjected to placebo LLLT (10.52mmoll−1 ± 1.82mmoll−1). LLLT irradiation before the Wingate test seemed to inhibit an expected post-exercise increase in CK level and to accelerate post-exercise lactate removal without affecting test performance. These findings suggest that LLLT may be of benefit in accelerating post-exercise recovery.
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The aim of this work is to analyze the effects of LED therapy at 940 nm or cold water immersion therapy (CWI) after an acute bout of exercise on markers of muscle damage and inflammation. Thirty-two male Wistar rats were allocated into four groups: animals kept at rest (control), exercised animals (E), exercised + CWI (CWI), and exercised + LED therapy (LED). The animals swam for 100 min, after which blood samples were collected for lactate analysis. Animals in the E group were returned to their cages without treatment, the CWI group was placed in cold water (10°C) for 10 min and the LED group received LED irradiation on both gastrocnemius muscles (4 J/cm(2) each). After 24 h, the animals were killed and the soleus muscles were submitted to histological analysis. Blood samples were used for hematological and CK analyses. The results demonstrated that the LED group presented fewer areas of muscle damage and inflammatory cell infiltration and lower levels of CK activity than the E group. Fewer areas of damaged muscle fiber were observed in the LED group than in CWI. CWI and LED did not reduce edema areas. Hematological analysis showed no significant effect of either treatment on leukocyte counts. The results suggest that LED therapy is more efficient than CWI in preventing muscle damage and local inflammation after exercise.
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Low-level laser therapy (LLLT) has shown efficacy in muscle bioenergetic activation and its effects could influence the mechanical performance of this tissue during physical exercise. This study tested whether endurance training associated with LLLT could increase human muscle performance in isokinetic dynamometry when compared to the same training without LLLT. The primary objective was to determine the fatigue index of the knee extensor muscles (FIext) and the secondary objective was to determine the total work of the knee extensor muscles (TWext). Included in the study were 45 clinically healthy women (21 ± 1.78 years old) who were randomly distributed into three groups: CG (control group), TG (training group) and TLG (training with LLLT group). The training for the TG and TLG groups involved cycle ergometer exercise with load applied to the ventilatory threshold (VT) for 9 consecutive weeks. Immediately after each training session, LLLT was applied to the femoral quadriceps muscle of both lower limbs of the TLG subjects using an infrared laser device (808 nm) with six 60-mW diodes with an energy of 0.6 J per diode and a total energy applied to each limb of 18 J. VT was determined by ergospirometry during an incremental exercise test and muscle performance was evaluated using an isokinetic dynamometer at 240°/s. Only the TLG showed a decrease in FIext in the nondominant lower limb (P = 0.016) and the dominant lower limb (P = 0.006). Both the TLG and the TG showed an increase in TWext in the nondominant lower limb (P < 0.001 and P = 0.011, respectively) and in the dominant lower limb (P < 0.000 and P < 0.000, respectively). The CG showed no reduction in FIext or TWext in either lower limb. The results suggest that an endurance training program combined with LLLT leads to a greater reduction in fatigue than an endurance training program without LLLT. This is relevant to everyone involved in sport and rehabilitation.
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The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots - 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.
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In the last years, phototherapy has becoming a promising tool to improve skeletal muscle recovery after exercise, however, it was not compared with other modalities commonly used with this aim. In the present study we compared the short-term effects of cold water immersion therapy (CWIT) and light emitting diode therapy (LEDT) with placebo LEDT on biochemical markers related to skeletal muscle recovery after high-intensity exercise. A randomized double-blind placebo-controlled crossover trial was performed with six male young futsal athletes. They were treated with CWIT (5°C of temperature [SD ±1°]), active LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW of output power, 30 s of irradiation time per point, and 41.7 J of total energy irradiated per point, total of ten points irradiated) or an identical placebo LEDT 5 min after each of three Wingate cycle tests. Pre-exercise, post-exercise, and post-treatment measurements were taken of blood lactate levels, creatine kinase (CK) activity, and C-reactive protein (CRP) levels. There were no significant differences in the work performed during the three Wingate tests (p > 0.05). All biochemical parameters increased from baseline values (p < 0.05) after the three exercise tests, but only active LEDT decreased blood lactate levels (p = 0.0065) and CK activity (p = 0.0044) significantly after treatment. There were no significant differences in CRP values after treatments. We concluded that treating the leg muscles with LEDT 5 min after the Wingate cycle test seemed to inhibit the expected post-exercise increase in blood lactate levels and CK activity. This suggests that LEDT has better potential than 5 min of CWIT for improving short-term post-exercise recovery.
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Recent studies have investigated whether low level laser therapy (LLLT) can optimize human muscle performance in physical exercise. This study tested the effect of LLLT on muscle performance in physical strength training in humans compared with strength training only. The study involved 36 men (20.8±2.2 years old), clinically healthy, with a beginner and/or moderate physical activity training pattern. The subjects were randomly distributed into three groups: TLG (training with LLLT), TG (training only) and CG (control). The training for TG and TLG subjects involved the leg-press exercise with a load equal to 80% of one repetition maximum (1RM) in the leg-press test over 12 consecutive weeks. The LLLT was applied to the quadriceps muscle of both lower limbs of the TLG subjects immediately after the end of each training session. Using an infrared laser device (808 nm) with six diodes of 60 mW each a total energy of 50.4 J of LLLT was administered over 140 s. Muscle strength was assessed using the 1RM leg-press test and the isokinetic dynamometer test. The muscle volume of the thigh of the dominant limb was assessed by thigh perimetry. The TLG subjects showed an increase of 55% in the 1RM leg-press test, which was significantly higher than the increases in the TG subjects (26%, P = 0.033) and in the CG subjects (0.27%, P < 0.001). The TLG was the only group to show an increase in muscle performance in the isokinetic dynamometry test compared with baseline. The increases in thigh perimeter in the TLG subjects and TG subjects were not significantly different (4.52% and 2.75%, respectively; P = 0.775). Strength training associated with LLLT can increase muscle performance compared with strength training only.
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The purpose of the present study was to determine the effect of low level laser therapy (LLLT) treatment before knee extensor eccentric exercise on indirect markers of muscle damage. Thirty-six healthy men were randomized in LLLT group (n = 18) and placebo group (n = 18). After LLLT or placebo treatment, subjects performed 75 maximal knee extensors eccentric contractions (five sets of 15 repetitions; velocity = 60° seg(-1); range of motion = 60°). Muscle soreness (visual analogue scale--VAS), lactate dehydrogenase (LDH) and creatine kinase (CK) levels were measured prior to exercise, and 24 and 48 h after exercise. Muscle function (maximal voluntary contraction--MVC) was measured before exercise, immediately after, and 24 and 48 h post-exercise. Groups had no difference on kineanthropometric characteristics and on eccentric exercise performance. They also presented similar baseline values of VAS (0.00 mm for LLLT and placebo groups), LDH (LLLT = 186 IU/l; placebo = 183 IU/l), CK (LLLT = 145 IU/l; placebo = 155 IU/l) and MVC (LLLT = 293 Nm; placebo = 284 Nm). VAS data did not show group by time interaction (P = 0.066). In the other outcomes, LLLT group presented (1) smaller increase on LDH values 48 h post-exercise (LLLT = 366 IU/l; placebo = 484 IU/l; P = 0.017); (2) smaller increase on CK values 24 h (LLLT = 272 IU/l; placebo = 498 IU/l; P = 0.020) and 48 h (LLLT = 436 IU/l; placebo = 1328 IU/l; P < 0.001) post-exercise; (3) smaller decrease on MVC immediately after exercise (LLLT = 189 Nm; placebo = 154 Nm; P = 0.011), and 24 h (LLLT = 249 Nm; placebo = 205 Nm; P = 0.004) and 48 h (LLLT = 267 Nm; placebo = 216 Nm; P = 0.001) post-exercise compared with the placebo group. In conclusion, LLLT treatment before eccentric exercise was effective in terms of attenuating the increase of muscle proteins in the blood serum and the decrease in muscle force.
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Randomized crossover double-blinded placebo-controlled trial. To investigate if low-level laser therapy (LLLT) can affect biceps muscle performance, fatigue development, and biochemical markers of postexercise recovery. Cell and animal studies have suggested that LLLT can reduce oxidative stress and inflammatory responses in muscle tissue. But it remains uncertain whether these findings can translate into humans in sport and exercise situations. Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes; lambda = 810 nm; 200 mW power output; 30 seconds of irradiation, applied in 2 locations over the biceps of the nondominant arm; 60 J of total energy) or placebo LLLT using an identical cluster probe. The intervention or placebo were applied 3 minutes before the performance of exercise. All subjects performed voluntary elbow flexion repetitions with a workload of 75% of their maximal voluntary contraction force until exhaustion. Active LLLT increased the number of repetitions by 14.5% (mean +/- SD, 39.6 +/- 4.3 versus 34.6 +/- 5.6; P = .037) and the elapsed time before exhaustion by 8.0% (P = .034), when compared to the placebo treatment. The biochemical markers also indicated that recovery may be positively affected by LLLT, as indicated by postexercise blood lactate levels (P<.01), creatine kinase activity (P = .017), and C-reactive protein levels (P = .047), showing a faster recovery with LLLT application prior to the exercise. We conclude that pre-exercise irradiation of the biceps with an LLLT dose of 6 J per application location, applied in 2 locations, increased endurance for repeated elbow flexion against resistance and decreased postexercise levels of blood lactate, creatine kinase, and C-reactiveprotein. Performance enhancement, level 1b.
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The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response.
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There are some indications that low-level laser therapy (LLLT) may delay the development of skeletal muscle fatigue during high-intensity exercise. There have also been claims that LED cluster probes may be effective for this application however there are differences between LED and laser sources like spot size, spectral width, power output, etc. In this study we wanted to test if light emitting diode therapy (LEDT) can alter muscle performance, fatigue development and biochemical markers for skeletal muscle recovery in an experimental model of biceps humeri muscle contractions. Ten male professional volleyball players (23.6 [SD +/-5.6] years old) entered a randomized double-blinded placebo-controlled crossover trial. Active cluster LEDT (69 LEDs with wavelengths 660/850 nm, 10/30 mW, 30 seconds total irradiation time, 41.7 J of total energy irradiated) or an identical placebo LEDT was delivered under double-blinded conditions to the middle of biceps humeri muscle immediately before exercise. All subjects performed voluntary biceps humeri contractions with a workload of 75% of their maximal voluntary contraction force (MVC) until exhaustion. Active LEDT increased the number of biceps humeri contractions by 12.9% (38.60 [SD +/-9.03] vs. 34.20 [SD +/-8.68], P = 0.021) and extended the elapsed time to perform contractions by 11.6% (P = 0.036) versus placebo. In addition, post-exercise levels of biochemical markers decreased significantly with active LEDT: Blood Lactate (P = 0.042), Creatine Kinase (P = 0.035), and C-Reative Protein levels (P = 0.030), when compared to placebo LEDT. We conclude that this particular procedure and dose of LEDT immediately before exhaustive biceps humeri contractions, causes a slight delay in the development of skeletal muscle fatigue, decreases post-exercise blood lactate levels and inhibits the release of Creatine Kinase and C-Reative Protein. Lasers Surg. Med. 41:572-577, 2009. (c) 2009 Wiley-Liss, Inc.
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To assess the clinical effectiveness of Low Level Laser Therapy (LLLT) in the treatment of tendinopathy. Secondary objectives were to determine the relevance of irradiation parameters to outcomes, and the validity of current dosage recommendations for the treatment of tendinopathy. LLLT is proposed as a possible treatment for tendon injuries. However, the clinical effectiveness of this modality remains controversial, with limited agreement on the most efficacious dosage and parameter choices. The following databases were searched from inception to 1(st) August 2008: MEDLINE, PubMed, CINAHL, AMED, EMBASE, All EBM reviews, PEDro (Physiotherapy Evidence Database), SCOPUS. Controlled clinical trials evaluating LLLT as a primary intervention for any tendinopathy were included in the review. Methodological quality was classified as: high (> or =6 out of 10 on the PEDro scale) or low (<6) to grade the strength of evidence. Accuracy and clinical appropriateness of treatment parameters were assessed using established recommendations and guidelines. Twenty-five controlled clinical trials met the inclusion criteria. There were conflicting findings from multiple trials: 12 showed positive effects and 13 were inconclusive or showed no effect. Dosages used in the 12 positive studies would support the existence of an effective dosage window that closely resembled current recommended guidelines. In two instances where pooling of data was possible, LLLT showed a positive effect size; in studies of lateral epicondylitis that scored > or =6 on the PEDro scale, participants' grip strength was 9.59 kg higher than that of the control group; for participants with Achilles tendinopathy, the effect was 13.6 mm less pain on a 100 mm visual analogue scale. LLLT can potentially be effective in treating tendinopathy when recommended dosages are used. The 12 positive studies provide strong evidence that positive outcomes are associated with the use of current dosage recommendations for the treatment of tendinopathy.
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The effect of photobiomodulation on delayed onset muscle soreness remains unknown. This study represents the first investigation of this treatment using an animal model. Seventy-two Sprague-Dawley rats were randomly divided into five groups: sedentary control group, exercise control group and three exercise-plus-laser groups. Downhill running was used to induce muscle injury in the gastrocnemius muscle. He-Ne laser irradiations were administered to the injured muscles immediately and at 18 and 42 h after exercise in the three exercise-plus-laser groups at 12, 28, and 43 J/cm2, respectively. Histological examination and serum creatine kinase (CK), muscle superoxide dismutase (SOD) and malondialdehyde (MDA) analyses were done at 24 and 48 h after exercise. The exercise control group exhibited a marked inflammation in the gastrocnemius muscle and significant elevations in serum CK activity and muscle MDA level after downhill running. He-Ne laser irradiation at 43 J/cm2 inhibited muscle inflammation, significantly enhanced muscle SOD activity and significantly reduced serum CK activity and muscle MDA level at both 24 and 48 h after exercise, whereas the irradiation at 12 or 28 J/cm2 slightly inhibited muscle inflammation and significantly reduced serum CK activity at 48 h after exercise only (P<0.05). Low-level He-Ne laser therapy could exert therapeutic effects on eccentric exercise-induced rat muscle injury through enhancing muscle anti-oxidative capacity and reducing the inflammatory reaction. The photobiomodulation was dose-dependent, and the 43 J/cm2 dose was the most efficient among the doses used.
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BACKGROUND DATA AND OBJECTIVE: There is anecdotal evidence that low-level laser therapy (LLLT) may affect the development of muscular fatigue, minor muscle damage, and recovery after heavy exercises. Although manufacturers claim that cluster probes (LEDT) maybe more effective than single-diode lasers in clinical settings, there is a lack of head-to-head comparisons in controlled trials. This study was designed to compare the effect of single-diode LLLT and cluster LEDT before heavy exercise. This was a randomized, placebo-controlled, double-blind cross-over study. Young male volleyball players (n = 8) were enrolled and asked to perform three Wingate cycle tests after 4 x 30 sec LLLT or LEDT pretreatment of the rectus femoris muscle with either (1) an active LEDT cluster-probe (660/850 nm, 10/30 mW), (2) a placebo cluster-probe with no output, and (3) a single-diode 810-nm 200-mW laser. The active LEDT group had significantly decreased post-exercise creatine kinase (CK) levels (-18.88 +/- 41.48 U/L), compared to the placebo cluster group (26.88 +/- 15.18 U/L) (p < 0.05) and the active single-diode laser group (43.38 +/- 32.90 U/L) (p < 0.01). None of the pre-exercise LLLT or LEDT protocols enhanced performance on the Wingate tests or reduced post-exercise blood lactate levels. However, a non-significant tendency toward lower post-exercise blood lactate levels in the treated groups should be explored further. In this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.
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The objective of this work was a further investigation of redox mechanisms of laser phototherapy on the cellular level. Cytochrome c oxidase, the terminal enzyme of the mitochondrial respiratory chain, is believed to work as the photoacceptor to modulate cellular metabolism in laser phototherapy. The changes in the absorption spectra of HeLa-cell monolayers before and after irradiation at 632.8 nm using fast multi-channel recording were evaluated by the intensity ratio between the peaks at 770 and 670 nm (intensity ratio criterion). By the intensity ratio criterion, the irradiation effects (reduction or oxidation of the photoacceptor) depended on the initial redox status of cytochrome c oxidase. The irradiation (three times at 632.8 nm, dose = 6.3 x 103 J/m(2), tau(irrad.) = 10 sec, tau(record.) = 600 msec) of cells initially characterized by relatively oxidized cytochrome c oxidase caused first a reduction of the photoacceptor, and then its oxidation (a bell-shaped curve). The irradiation by the same scheme of the cells with initially relatively reduced cytochrome c oxidase caused first oxidation and then a slight reduction of the enzyme (a curve opposite to the bell-shaped curve). The experimental results of our work demonstrate that irradiation at 632.8 nm causes either a (transient) relative reduction of the photoacceptor, putatively cytochrome c oxidase, or its (transient) relative oxidation, depending on the initial redox status of the photoacceptor. The maximum in the bell-shaped dose-dependence curve or the minimum of the reverse curve is the turning point between the prevailing of oxidation or reduction processes. Our results are evidence that the bell-shaped dose dependences recorded for various cellular responses are characteristic also for redox changes in the photoacceptor, cytochrome c oxidase.
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We used statistical meta-analysis to determine the overall treatment effects of laser phototherapy on tissue repair and pain relief. Low-power laser devices were first used as a form of therapy more than 30 years ago. However, their efficacy in reducing pain or promoting tissue repair remains questionable. Following a literature search, studies meeting our inclusion criteria were identified and coded. Then, the effect size of laser treatment, that is, Cohen's d, was calculated from each study using standard meta-analysis procedures. Thirty-four peer-reviewed papers on tissue repair met our inclusion criteria and were used to calculate 46 treatment effect sizes. Nine peer-reviewed papers on pain control met the inclusion criteria and were used to calculate nine effect sizes. Meta-analysis revealed a positive effect of laser phototherapy on tissue repair (d = +1.81; n = 46) and pain control (d = +1.11; n = 9). The positive effect of treatment on specific indices of tissue repair was evident in the treatment effect sizes determined as follows: collagen formation (d = +2.78), rate of healing (d = +1.57), tensile strength (d = +2.13), time needed for wound closure (d = +0.76), tensile stress (d = +2.65), number and rate of degranulation of mast cells (d = +1.87), and flap survival (d = +1.95). Further, analysis revealed the positive effects of various wavelengths of laser light on tissue repair, with 632.8 nm having the highest treatment effect (d = +2.44) and 780 nm the least (d = 0.60). The overall treatment effect for pain control was positive as well (d = +1.11). The fail-safe number-that is, the number of studies in which laser phototherapy has negative or no effect-needed to nullify the overall outcome of this analysis was 370 for tissue repair and 41 for pain control. These findings mandate the conclusion that laser phototherapy is a highly effective therapeutic armamentarium for tissue repair and pain relief.
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The aim of the present work is to analyze available action spectra for various biological responses of HeLa cells irradiated with monochromatic light of 580-860 nm. Phototherapy (low-level laser therapy or photobiomodulation) is characterized by its ability to induce photobiological processes in cells. Exact action spectra are needed for determination of photoacceptors as well as for further investigations into cellular mechanisms of phototherapy. Seven action spectra for the stimulation of DNA and RNA synthesis rate and cell adhesion to glass matrix are analyzed by curve fitting, followed by deconvolusion with Lorentzian fitting. Exact parameters of peak positions and bandwidths are presented. The peak positions are between 613.5 and 623.5 nm (in one spectrum, at 606 nm), in the red maximum. The far-red maximum has exact peak positions between 667.5 and 683.7 nm in different spectra. Two near infrared maxima have peak positions in the range 750.7-772.3 nm and 812.5-846.0 nm, respectively. In the wavelength range important for phototherapy (600-860 nm), there are four "active" regions, but peak positions are not exactly the same for all spectra.
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We investigated whether low-level laser therapy (LLLT) can reduce muscular fatigue during tetanic contractions in rats. Thirty-two male Wistar rats were divided into four groups receiving either one of three different LLLT doses (0.5, 1.0, and 2.5 J/cm2) or a no-treatment control group. Electrical stimulation was used to induce six tetanic muscle contractions in the tibial anterior muscle. Contractions were stopped when the muscle force fell to 50% of the initial value for each contraction (T50%). There was no significant difference between the 2.5 J/cm2 laser-irradiated group and the control group in mean T50% values. Laser-irradiated groups (0.5 and 1.0 J/cm2) had significantly longer T50% values than the control group. The relative peak force for the sixth contraction in the laser-irradiated groups were significantly higher at 92.2% (SD 12.6) for 0.5 J/cm2, 83.2% (SD 20.5) for 1.0 J/cm2, and 82.9% (SD 18.3) for 2.5 J/cm2 than for the control group [50% (SD 15)]. Laser groups receiving 0.5 and 1.0 J/cm2 showed significant increases in mean performed work compared with both the control group and their first contraction values. Muscle damage was indirectly measured by creatine kinase levels in plasma. A distinct dose-response pattern was found in which 1.0 and 2.5 J/cm2 LLLT groups had significantly lower creatine kinase levels than the 0.5 J/cm2 LLLT group and the control group. We conclude that LLLT doses of 0.5 and 1.0 J/cm2 can prevent development of muscular fatigue in rats during repeated tetanic contractions.
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To describe the physiological responses to tournament tennis in relation to prevailing environmental conditions, match notation, and skills that underpin performance. 14 male professional tennis players (mean (SD) age, 21.4 (2.6) years; height, 183.0 (6.9) cm; body mass, 79.2 (6.4) kg) were studied while contesting international tennis tournaments. Environmental conditions, match notation, physiological (core temperature, hydration status, heart rate, blood variables), and performance indices (serve kinematics, serve velocity, error rates) were recorded. Hard and clay court tournaments elicited similar peak core temperature (38.9 (0.3) v 38.5 (0.6) degrees C) and average heart rate (152 (15) v 146 (19) beats/min) but different body mass deficit (1.05 (0.49) v 0.32 (0.56)%, p<0.05). Average pre-match urine specific gravity was 1.022 (0.004). Time between points was longer during hard court matches (25.1 (4.3) v 17.2 (3.3) s, p<0.05). Qualitative analysis of first and second serves revealed inverse relations between the position of the tossing arm at ball release and the position of the ball toss and progressive match time (respectively, r = -0.74 and r = -0.73, p<0.05) and incurred body mass deficit (r = 0.73 and r = 0.73, p<0.05). Participants began matches in a poor state of hydration, and experienced moderate thermoregulatory strain and dehydration during competition. These adverse physiological conditions may compromise performance and influence notational analyses.