Effect of photobiomodulation therapy on performance and running economy in runners: A randomized double-blinded placebo-controlled trial.

The objective of this study was to evaluate effects of photobiomodulation therapy (PBMT) on the 3000 m running performance (primary outcome), running economy (RE), metabolic cost and ratings of perceived exertion during running (secondary outcomes). Twenty male endurance athletes performed 4-min treadmill rectangular test at 12 km.h-1 monitored by a gas analyser. After that, PBMT or placebo in each lower limb was applied, followed performed a maximum test of 3000 m. Immediately after 3000 m test, the athletes repeated the treadmill test. Another application of PBMT/placebo was done after the treadmill test, and athletes went back to the laboratory 24 h later to repeat the treadmill test. After a 72 h interval, athletes repeated all procedures with another treatment intervention (PBMT/placebo). Athletes performed the 3000 m running test ~7s faster when treated with PBMT with similar effort score compared placebo condition. The RE remains unchanged immediately post 3000 m running test, nonetheless RE measured post-24 h improved by 5% with PBMT application without changes in metabolic cost. The PBMT pre- and post-conditioning enhanced the 3000 m running performance and improved RE 24 h following the 3000 m test. However, no changes on ratings of perceived exertion and metabolic cost with the application of PBMT.

Kinematic Comparison of the Roundhouse Kick Between Taekwondo, Karate, and Muaythai.

ABSTRACT: Diniz, R, Del Vecchio, FB, Schaun, GZ, Oliveira, HB, Portella, EG, da Silva, ES, Formalioni, A, Campelo, PCC, Peyré-Tartaruga, LA, and Pinto, SS. Kinematic comparison of the roundhouse kick between taekwondo, karate, and muaythai. J Strength Cond Res 35(1): 198-204, 2021-The roundhouse kick (RHK) is frequently executed in taekwondo, karate, and muaythai because of its high technical effectiveness during combat. The purpose of this study was to compare kinematic characteristics during RHK performance between taekwondo, karate, and muaythai athletes. Forty-seven male athletes (25.5 ± 4.7 years, 1.75 ± 0.1 m, and 75.8 ± 11.5 kg) volunteered to participate (taekwondo: 17; karate: 15; and muaythai: 15). Self-selected distance from target, mean and peak fifth metatarsus linear velocity (LV5mean; LV5peak), mean and peak hip (HAVmean; HAVpeak) and knee (KAVmean; KAVpeak) angular velocities, as well as target linear acceleration (TLA) were analyzed with a 3D video motion analysis system. Comparisons between modalities were performed with 1-way analysis of variances and Bonferroni's post hoc test (α = 0.05). Self-selected distance was lower in muaythai compared with taekwondo and karate (p < 0.001). Also, karate had greater LV5mean compared with muaythai (p = 0.001), and muaythai showed higher HAVmean than karate (p = 0.011). In addition, HAVpeak was greater in muaythai than in taekwondo and karate (p < 0.001). No differences were found for KAVmean, KAVpeak, and TLA. Although it is similarly described between modalities, RHK showed distinct kinematic characteristics between taekwondo, karate, and muaythai. Based on these results, coaches and athletes can improve their RHK technique according to the specificities of each combat sport. Specifically, it is suggested that combat strategies should aim to increase the distance from the opponent during combat for muaythai athletes, whereas taekwondo and karate athletes should focus on decreasing it.

Physiological Predictors of Maximal Incremental Running Performance.

PURPOSE: The aim of this study was to verify whether physiological components [vertical jumps (Squat Jump - SJ and Countermovement Jump - CMJ), eccentric utilization ratio (EUR) of vertical jumps, running economy (RE), metabolic cost (C MET ), first and second ventilatory threshold (VT1 and VT2) maximal oxygen uptake (VO2MAX)] can predict maximal endurance running performance. METHODS: Twenty male runners performed maximal vertical jumps, submaximal running at constant speeds, and maximal incremental running test. Before, we measured anthropometric parameters (body mass and height) and registered the training history and volume. SJ and CMJ tests were evaluated prior to running tests. Initially, the oxygen uptake (VO2) was collected at rest in the orthostatic position for 6 min. Soon after, a 10-min warm-up was performed on the treadmill at 10 km⋅h-1, followed by two 5-min treadmill rectangular tests at 12 and 16 km⋅h-1 monitored by a gas analyzer. After that, the runners performed a maximal incremental test, where the VT1, VT2, and VO2MAX were evaluated, as well as the maximum running speed (vVO2MAX). Thus, RE and C MET were calculated with data obtained during rectangular running tests. Multivariate stepwise regression analyses were conducted to measure the relationship between independent variables (height and power of SJ and CMJ, EUR; RE and C MET 12 and 16 km⋅h-1 ; VT1, VT2, and VO2MAX), as predictors of maximal running performance (vVO2MAX), with significance level at α = 0.05. RESULTS: We found that VO2MAX and RE at 16 km⋅h-1 predict 81% of performance (vVO2MAX) of endurance runners (p < 0.001). CONCLUSION: The main predictors of the maximal incremental running test performance were VO2MAX and RE.

Sprint exercise for subjects with mild-to-moderate Parkinson's disease: Feasibility and biomechanical outputs.

BACKGROUND: High-intensity training, a still unexplored exercise for individuals with Parkinson's disease, is positively related with increased functionality and aerobic profile in healthy individuals. The aim of this work was to evaluate the feasibility, safety, and acceptance of sprint running in individuals with mild-to-moderate Parkinson's. Additionally, we compared sprint biomechanical outputs of force, velocity and power between individuals with Parkinson's disease and healthy. METHODS: Physically trained subjects with Parkinson's, men, (n = 16, 64:9.01 years, stage between 1 and 3 in the Hoehn and Yahr, 16.8:7.1 at Unified Parkinson's disease Rating Scales, and control group (n = 21, 65:9.27 years) performed 20 m sprint sessions. We analyzed the self-reported satisfaction and acceptance using a self-administered questionnaire, and the sprint biomechanics and performance based on high-speed video recordings. FINDINGS: All participants completed the tests with high feasibility, acceptability and satisfaction scores. The sprint maximal force and maximal power outputs were higher in Parkinson's disease. Conversely, control group showed higher mechanical effectiveness values. Interestingly, no difference in velocity capabilities and overall 20-m sprint performance was observed between groups, possibly explained by different mechanical strategies in both groups over the sprint accelerations. Linear regression analyses showed that physical qualities are predictors of mechanical effectiveness, and mechanical variables are important determinants of sprint performance on Parkinson's disease. INTERPRETATION: Sprint is a feasible exercise for people with mild-to-moderate Parkinson's disease. Even though differences in physical qualities and mechanical effectiveness exist between subjects with Parkinson's disease and healthy, there is no overall substantial impact on sprint running performance.

Physical Activity and Incident Depression: A Meta-Analysis of Prospective Cohort Studies.

OBJECTIVE: The authors examined the prospective relationship between physical activity and incident depression and explored potential moderators. METHOD: Prospective cohort studies evaluating incident depression were searched from database inception through Oct. 18, 2017, on PubMed, PsycINFO, Embase, and SPORTDiscus. Demographic and clinical data, data on physical activity and depression assessments, and odds ratios, relative risks, and hazard ratios with 95% confidence intervals were extracted. Random-effects meta-analyses were conducted, and the potential sources of heterogeneity were explored. Methodological quality was assessed using the Newcastle-Ottawa Scale. RESULTS: A total of 49 unique prospective studies (N=266,939; median proportion of males across studies, 47%) were followed up for 1,837,794 person-years. Compared with people with low levels of physical activity, those with high levels had lower odds of developing depression (adjusted odds ratio=0.83, 95% CI=0.79, 0.88; I2=0.00). Furthermore, physical activity had a protective effect against the emergence of depression in youths (adjusted odds ratio=0.90, 95% CI=0.83, 0.98), in adults (adjusted odds ratio=0.78, 95% CI=0.70, 0.87), and in elderly persons (adjusted odds ratio=0.79, 95% CI=0.72, 0.86). Protective effects against depression were found across geographical regions, with adjusted odds ratios ranging from 0.65 to 0.84 in Asia, Europe, North America, and Oceania, and against increased incidence of positive screen for depressive symptoms (adjusted odds ratio=0.84, 95% CI=0.79, 0.89) or major depression diagnosis (adjusted odds ratio=0.86, 95% CI=0.75, 0.98). No moderators were identified. Results were consistent for unadjusted odds ratios and for adjusted and unadjusted relative risks/hazard ratios. Overall study quality was moderate to high (Newcastle-Ottawa Scale score, 6.3). Although significant publication bias was found, adjusting for this did not change the magnitude of the associations. CONCLUSIONS: Available evidence supports the notion that physical activity can confer protection against the emergence of depression regardless of age and geographical region.

Psychocultural Mechanisms of the Propensity toward Criminal Homicide: A Multidimensional View of the Culture of Honor.

Introduction: Theory of the Culture of Honor is one of the few models in criminology specifically geared toward homicide. It proposes that, in certain societies, men must never show weakness and are required to react violently to any perceived threats to their reputation, thereby increasing their probability of committing a homicide. This has been suggested as the main explanation for the high rates of this type of crime in Brazil, particularly in the Northeast. Underlying this explanation there are complex mechanisms and processes that have yet to be clarified. Objectives: The present research aimed to investigate the workings of the possible psychocultural mechanisms underlying the culture of honor and the process through which they might affect the individual propensity toward homicide. Methods: A total of 336 Brazilian adults were assessed regarding a broad range of sociodemographic, psychological, and sociocultural variables, including their attitudes toward homicide. The resulting dataset was analyzed using Smallest Space Analysis and Facet Theory. Results: It seems that certain cultural elements associated to traditional masculinity and enhanced anger tend to promote negative personality traits and increase one's propensity toward committing homicide. Conclusion: The findings obtained not only confirm the Theory of the Culture of Honor for the propensity toward homicide, but also explicit and clarify some of the psychocultural processes and mechanisms involved, suggesting a new scientific framework.