Thiago De Marchi

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

STUDY DESIGN Randomized crossover double-blinded placebo-controlled trial. OBJECTIVE To investigate if low-level laser therapy (LLLT) can affect biceps muscle performance, fatigue development, and biochemical markers of postexercise recovery. BACKGROUND Cell and animal studies have suggested that LLLT can reduce oxidative stress and inflammatory responses in muscle tissue. But it remains uncertain whether these findings can translate into humans in sport and exercise situations. METHODS Nine healthy male volleyball players participated in the study. They received either active LLLT (cluster probe with 5 laser diodes; 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. RESULTS 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. CONCLUSION We conclude that pre-exercise irradiation of the biceps with an LLLT dose of 6 J per application location, applied in 2 locations, increased endurance for repeated elbow flexion against resistance and decreased postexercise levels of blood lactate, creatine kinase, and C-reactiveprotein. LEVEL OF EVIDENCE Performance enhancement, level 1b.

Effect of Cluster Multi-Diode Light Emitting Diode Therapy (LEDT) on Exercise-Induced Skeletal Muscle Fatigue and Skeletal Muscle Recovery in Humans

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.

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

BACKGROUND DATA AND OBJECTIVE There is anecdotal evidence that low-level laser therapy (LLLT) may affect the development of muscular fatigue, minor muscle damage, and recovery after heavy exercises. Although manufacturers claim that cluster probes (LEDT) maybe more effective than single-diode lasers in clinical settings, there is a lack of head-to-head comparisons in controlled trials. This study was designed to compare the effect of single-diode LLLT and cluster LEDT before heavy exercise. MATERIALS AND METHODS This was a randomized, placebo-controlled, double-blind cross-over study. Young male volleyball players (n = 8) were enrolled and asked to perform three Wingate cycle tests after 4 x 30 sec LLLT or LEDT pretreatment of the rectus femoris muscle with either (1) an active LEDT cluster-probe (660/850 nm, 10/30 mW), (2) a placebo cluster-probe with no output, and (3) a single-diode 810-nm 200-mW laser. RESULTS The active LEDT group had significantly decreased post-exercise creatine kinase (CK) levels (-18.88 +/- 41.48 U/L), compared to the placebo cluster group (26.88 +/- 15.18 U/L) (p < 0.05) and the active single-diode laser group (43.38 +/- 32.90 U/L) (p < 0.01). None of the pre-exercise LLLT or LEDT protocols enhanced performance on the Wingate tests or reduced post-exercise blood lactate levels. However, a non-significant tendency toward lower post-exercise blood lactate levels in the treated groups should be explored further. CONCLUSION In this experimental set-up, only the active LEDT probe decreased post-exercise CK levels after the Wingate cycle test. Neither performance nor blood lactate levels were significantly affected by this protocol of pre-exercise LEDT or LLLT.

Phototherapy for Improvement of Performance and Exercise Recovery: Comparison of 3 Commercially Available Devices

CONTEXT   Recent studies suggest the prophylactic use of low-powered laser/light has ergogenic effects on athletic performance and postactivity recovery. Manufacturers of high-powered lasers/light devices claim that these can produce the same clinical benefits with increased power and decreased irradiation time; however, research with high-powered lasers is lacking. OBJECTIVE   To evaluate the magnitude of observed phototherapeutic effects with 3 commercially available devices. DESIGN   Randomized double-blind placebo-controlled study. SETTING   Laboratory. PATIENTS OR OTHER PARTICIPANTS   Forty healthy untrained male participants. INTERVENTION(S)   Participants were randomized into 4 groups: placebo, high-powered continuous laser/light, low-powered continuous laser/light, or low-powered pulsed laser/light (comprising both lasers and light-emitting diodes). A single dose of 180 J or placebo was applied to the quadriceps. MAIN OUTCOME MEASURE(S)   Maximum voluntary contraction, delayed-onset muscle soreness (DOMS), and creatine kinase (CK) activity from baseline to 96 hours after the eccentric exercise protocol. RESULTS   Maximum voluntary contraction was maintained in the low-powered pulsed laser/light group compared with placebo and high-powered continuous laser/light groups in all time points (P < .05). Low-powered pulsed laser/light demonstrated less DOMS than all groups at all time points (P < .05). High-powered continuous laser/light did not demonstrate any positive effects on maximum voluntary contraction, CK activity, or DOMS compared with any group at any time point. Creatine kinase activity was decreased in low-powered pulsed laser/light compared with placebo (P < .05) and high-powered continuous laser/light (P < .05) at all time points. High-powered continuous laser/light resulted in increased CK activity compared with placebo from 1 to 24 hours (P < .05). CONCLUSIONS   Low-powered pulsed laser/light demonstrated better results than either low-powered continuous laser/light or high-powered continuous laser/light in all outcome measures when compared with placebo. The increase in CK activity using the high-powered continuous laser/light compared with placebo warrants further research to investigate its effect on other factors related to muscle damage.

A fototerapia com diodo emissor de luz (LEDT) aplicada pré-exercício inibe a peroxidação lipídica em atletas após exercício de alta intensidade: um estudo preliminar

Oxidative stress is the term generally used to describe the damage caused by imbalance between pro-oxidants and antioxidants in the organism. The increase in the O2 consumption induced by physical exercise is associated with the increase of reactive oxygen species (ROS) being these species inducers of oxidative stress. Although the evidence indicates a probable inhibitory effect of the light emitting diode therapy (LEDT) on the production of ROS, there are no studies observing this effect in humans. This preliminary study has the aim to verify the effects of LEDT applied before high-intensity exercise on lipid peroxidation, measured through blood levels of reactive substances to thiobarbituric acid (TBARS). Six male volleyball athletes were submitted to two situations: active LEDT and placebo LEDT. Performance in the exercise protocol showed no difference (p> 0.05) between the two situations in peak power, average power and fatigue index. The results related to lipid peroxidation were: at active LEDT situation, it was not possible to observe statistically significant difference (p>0.05) between pre and post exercise levels (6.98 ± 0.81 and 7.02 ± 0.47 nmol/mL); at placebo LEDT situation, statistically significant difference (p=0.05) was observed between pre and post exercise levels (7.09 ± 1.28 and 8.43 ± 0.71 nmol/mL). These results show that active LEDT seems to be effective in controlling lipid peroxidation in athletes submitted to intense exercise

What is the ideal dose and power output of low-level laser therapy (810 nm) on muscle performance and post-exercise recovery? Study protocol for a double-blind, randomized, placebo-controlled trial

BackgroundRecent studies involving phototherapy applied prior to exercise have demonstrated positive results regarding the attenuation of muscle fatigue and the expression of biochemical markers associated with recovery. However, a number of factors remain unknown, such as the ideal dose and application parameters, mechanisms of action and long-term effects on muscle recovery. The aims of the proposed project are to evaluate the long-term effects of low-level laser therapy on post-exercise musculoskeletal recovery and identify the best dose andapplication power/irradiation time.Design and methodsA double-blind, randomized, placebo-controlled clinical trial with be conducted. After fulfilling the eligibility criteria, 28 high-performance athletes will be allocated to four groups of seven volunteers each. In phase 1, the laser power will be 200 mW and different doses will be tested: Group A (2 J), Group B (6 J), Group C (10 J) and Group D (0 J). In phase 2, the best dose obtained in phase 1 will be used with the same distribution of the volunteers, but with different powers: Group A (100 mW), Group B (200 mW), Group C (400 mW) and Group D (0 mW). The isokinetic test will be performed based on maximum voluntary contraction prior to the application of the laser and after the eccentric contraction protocol, which will also be performed using the isokinetic dynamometer. The following variables related to physical performance will be analyzed: peak torque/maximum voluntary contraction, delayed onset muscle soreness (algometer), biochemical markers of muscle damage, inflammation and oxidative stress.DiscussionOur intention, is to determine optimal laser therapy application parameters capable of slowing down the physiological muscle fatigue process, reducing injuries or micro-injuries in skeletal muscle stemming from physical exertion and accelerating post-exercise muscle recovery. We believe that, unlike drug therapy, LLLT has a biphasic dose–response pattern.Trial registrationThe protocol for this study is registered with the Protocol Registry System, ClinicalTrials.gov identifier NCT01844271.

Treatment of the Aged Patients at a Large Cardiac Rehabilitation Center in the Southern Brazil and Some Aspects of Their Dropout from the Therapeutic Programs

AIM: This paper aims to assess the dropout rate in different age groups through the example of the large cardiac rehabilitation centre affiliated with the Institute of Sports Medicine, University of Caxias do Sul. MATERIAL AND METHODS: A historic cohort study comprising the following groups: Non-Old < 65 (n = 141); Young-Old 65-74 (n = 128); and Middle-Old 75-84 years old (n = 57). The exercise program lasted 48 sessions and dropout was defined as attendance of 50% of sessions or less. Logistic binominal regression was performed to assess the risk of dropout. For all analyses, a two-tailed P value of < 0.05 was used. RESULTS: The total dropout rate was 38.6%. The Young-Old and Middle-Old groups showed lower dropouts compared to Non-Old patients (p = 0.01). Young-Old has 96% less risk for dropout compared to Non-Old group (adjusted odds ratios = 1.96 [1.16–3.29]). Furthermore, patients underwent the Coronary Artery Bypass Graft showed a lower rate of dropout (p = 0.001). The absence of CABG involved three times more risk of dropout (p = 0.001). CONCLUSION: The Non-Old and the Middle-Old patients showed higher dropout rates compared to Young-Old. To ensure the best possible rehabilitation and to improve patients´ participation in CR, these programs should be adjusted to the needs of patients in terms of their age.

Analysis of Cardiovascular Disease Risk Factors in Women

AIM: Study the cardiovascular risk factors in a feminine population vulnerable to cardiovascular events particularly to evaluate the principal factors or possible confounding variables. METHODS: This is a cross-sectional descriptive study. Were analysed all the female patients from the Cardiovascular Rehabilitation Institute of Sports Medicine of Caxias do Sul who had the complete information on cardiovascular disease history, comorbidities and habits and who knew the complete gynaecological history by a phone interview. RESULTS: A group of 91 patients were analysed. About the comorbidities and habits, 45.2% of these patients presented some tobacco load, 82.4% are hypertensive, 61.5% are dyslipidemic, 25.3% are diabetic and the BMI average was 29.27 (overweight). Between the patients who undergone a hysterectomy and had an episode of the acute coronary syndrome (10 patients), 70% had the event after the procedure. Between the post-menopause women with at least one episode of the acute coronary syndrome, 80.5% (33 patients) had the first event after the menopause. CONCLUSION: We found multiple lifetime risk factors that predisposed the women of the sample to have cardiovascular disease. Between the women with specific to women risk factors and without, the prevalence of cardiovascular disease was very similar. This information supports the idea that these are just confounding factors of CVD and the principals involved are the genetic factors and habits. For this reason, the focus of CVD prevention and treatment should be directed towards these aspects.

Comment on “Photobiomodulation delays the onset of skeletal muscle fatigue in a dose-dependent manner”

Dear Editor in Chief, I am writing regarding the manuscript BPhotobiomodulation delays the onset of skeletal muscle fatigue in a dose-dependent manner^ authored by Larkin-Kaiser et al. [1]. The authors state that the work done was adding new information to the field of photobiomodulation (PBM). However, the finding of this manuscript only confirms that the use of high-powered lasers is not effective for enhancing sports performance or accelerating recovery. The use of a large dose (240 J to enhance performance of a very small muscle—first dorsal interosseous) seems excessive when low-powered lasers need only 180 J to improve performance of large muscle groups such as knee extensors [2–6] in fact, very recently, a head-to-head comparison between three commercially available devices showed that high-powered lasers show worst outcomes when compared to low-powered lasers/LEDs. There was an obvious absence of articles cited in manuscript [1] that detail optimal parameters, including dose ranges [4, 7] for the use of PBM for muscle enhancement. More curiously, authors did not include two recently published systematic reviews, one of them authored by the senior author of this article [8, 9], which could be valuable in a discussion regarding parameters and dose ranges. Authors use the term Bdose dependent manner^, however, the study design did not include a minimum of three active doses and a placebo comparator. The lack of adequate data points would not provide any plausible notion of the action of the delivered dose along the ArndtShutz curve. T h e a r t i c l e t i t l e c o n t a i n s t h e MeSH t e rm BPhotobiomodulation^. It should be noted that Joensen et al. [10] have demonstrated that light devices that deliver more than 200 mWof power can significantly increase skin temperature. How is it then possible that a high-powered class 4 laser applying 2 and 4 W for a 2-min duration not increase a subjects’ skin temperature? According to the editorial published by Anders et al. [11] regarding photobiomodulation: BThe use of this term is key, as it distinguishes photobiomodulation therapy, which is nonthermal, from the popular use of light based devices for simple heating of tissues [...]^, therefore, this term should not have been included in this manuscript. The introduction is problematic. The authors state, BPhotobiomodulation (PBM) therapy is the medicinal use of both low and high intensity light sources [...]^. Several editorial published by experts in the field do not support the use of high intensity sources [11, 12]. The inclusion of wavelengths beyond 1000 nm was included in the manuscript; however, the references used to endorse this statement (refs. [4], [5] and [11] of Larkin-Kaiser et al. [1] manuscript) used wavelengths below 1000 nm. The intentional use of overstatements and false statements is meant to intentionally misled readers into thinking high-powered laser is included in photobiomodulation. Several additional biases exist in the paper:

Desempenho isocinético dos músculos do joelho de atletas de futsal durante a pré-temporada e o meio de temporada

72 ABSTRACT Futsal is a multiple sprint that require constant changes in direction, speed, kicks and tackles, therefore the lower limbs, and specifically the knee muscles, play a crucial role during these futsal’s actions, as the intense demands put on athletes during a futsal regular season can result in muscle imbalances between the lower limbs and between the extensor and flexor muscles of the knee, thereby, decreasing the muscular performance and increasing the risk of knee injuries. Objective: The aims of this study were to analyze the lower limbs differences after the demands of a regular season on the knee’s muscles’ strength, and the relations between the extensor and flexor muscles. Method: Data on 15 professional futsal players at pre-season and middle-season, provided by a database were analyzed. The database provided data from isokinetic dynamometer evaluations in a concentric-concentric mode for the knee extensor and flexor muscles at angular velocities of 60°/s, 120°/s, 180°/s and 240°/s. Results: No significant differences in peak torque (PT) of the extensor and flexor muscles, and of the flexor/extensor ratios were found between the limbs when compared at the same angular velocity and at the same time, either pre-season or middle-season. However, the PT values for the middle-season were almost always significantly higher when compared to the pre-season. Conclusion: These findings indicate that the training prescribed during the season was adequate and allowed to increase the muscle strength and also prevented imbalances.