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To evaluate the effects of 12-weeks of walk training with self-selected intensity on lipid profile and anthropometric variables in women with obesity. Forty-eight women volunteers with obesity were randomly assigned into two training groups: self-selected walking group (SSWG; n=25) and control group (CG; n=23). There was improvement in biochemical markers only in the SSWG post-intervention (p<0.05), however no changes were verified in anthropometric variables (p>0.05). This study demonstrates that walking at self-selected intensity improved the lipid profile in women with obesity.

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This study compared training load and ratings of perceived exertion (RPE) during resistance training (RT) and aerobic training (AT) sessions at self-selected intensity. Participants were 54 recreationally trained subjects assigned to either RT or AT groups. During RT, participants performed three sets of 10 repetitions of each exercise at a self-selected intensity (load). After RT completion, participants performed one repetition maximum (1RM) and 10RM tests. During AT, participants performed a treadmill exercise at a self-selected intensity and duration (velocity and time). After AT completion, participants performed a treadmill maximal exercise test using a ramp protocol. During RT, subjects chose an intensity (43.6%-60.2% 1RM) below typical training recommendations, and RPE increased in successive exercise sets. During AT, participants chose an intensity (83.9% Heart Ratepeak) in line with typical training recommendations, and RPE increased from the first to second quartile of the session (from a mean of 3.9, standard deviation [ SD] = 1.7 to a mean of 5.4, SD = 1.7; p < .05) and remained stable thereafter. These recreationally trained participants self-selected lower RT intensities than are typically recommended for strength and hypertrophy increases (>67% 1RM) and AT intensities in line with typically recommended intensity (64%-95% HRmax) for cardiovascular fitness increases. Thus, for recreational trained individuals to perform RT at recommended intensities, specific instruction will be required.

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PURPOSE/BACKGROUND: Strength asymmetries are related to knee injuries in intermittent sports players. The purpose of this study was to examine whether elite futsal players demonstrate strength asymmetries during knee isokinetic testing applying the Croisier et al.21 criteria. METHODS: Forty male elite (27.9 ± 6.5 years) Brazilian futsal players participated in the study. The testing protocol required players to perform concentric contractions of both quadriceps and hamstring muscles at angular velocities of 60 °·s-1 and 240 °·s-1 and eccentric contractions of hamstring at 30 °·s-1 and 120 °·s-1. Conventional (concentric:concentric) and mixed (eccentric:concentric) hamstrings/quadriceps (H/Q) ratios were calculated. Subjects were determined to have an imbalanced strength profile if an athlete had at least two parameters that were asymmetrical across speeds and conditions. Asymmetry was operationally defined as peak torque asymmetry greater than 15% in bilateral comparison, and H/Q ratio less than 0.47 for conventional and 0.80 for mixed conditions. RESULTS: Significant differences were observed between preferred and nonpreferred limbs in the concentric contractions of flexors at 240 °·s-1 and eccentric contractions of extensors and flexors at 30 °·s-1 and 120 °·s-1. However, these asymmetries did not exceed 15%. The conventional and mixed H/Q ratios were greater in the preferred than in nonpreferred limbs, but only the mixed hamstringsecc/quadricepsconc in the nonpreferred limbs showed values lower than recommended (<0.80). In addition, 50% of elite futsal players had preseason strength imbalances per the developed criteria. CONCLUSION: The studied elite futsal players had preseason strength imbalances, which may increase the risk of hamstring injuries. LEVEL OF EVIDENCE: 3.

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This study examined the extent to which different high-intensity interval training (HIIT) and sprint interval training (SIT) protocols could influence psychophysiological responses in moderately active young men. Fourteen participants completed, in a randomized order, three cycling protocols (SIT: 4 × 30-second all-out sprints; Tabata: 7 × 20 seconds at 170% ⋮O2max; and HIIT: 10 × 60 seconds at 90% HRmax) and three running HIIT protocols (4 × 4 minutes at 90%-95% HRmax, 5 × at v⋮O2max, and 4 × 1,000 meters at a rating of perceived exertion (RPE) of 8, from the OMNI-Walk/Run scale). Oxygen uptake (⋮O2), heart rate, and RPE were recorded during each interval. Affective responses were assessed before and after each trial. The Tabata protocol elicited the highest ⋮O2 and RPE responses, and the least pleasant session-affect among the cycling trials. The v⋮O2max elicited the highest ⋮O2 and RPE responses and the lowest mean session-affect among the running trials. Findings highlight the limited application of SIT and some HIIT protocols to individuals with low fitness levels.

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BACKGROUND: To determine the effects of a low dose, short-term Creatine monohydrate (Cr) supplementation (0.03 g.kg.d-1 during 14 d) on muscle power output in elite youth soccer players. METHODS: Using a two-group matched, double blind, placebo-controlled design, nineteen male soccer players (mean age = 17.0 ± 0.5 years) were randomly assigned to either Cr (N = 9) or placebo (N = 10) group. Before and after supplementation, participants performed a 30s Wingate Anaerobic Test (WAnT) to assess peak power output (PPO), mean power output (MPO), fatigue index (FI), and total work. RESULTS: There were significant increases in both PPO and MPO after the Cr supplementation period (P ≤ 0.05) but not the placebo period. There were also significant increases in total work, but not FI, after the Cr supplementation and placebo periods (P ≤ 0.05). Notably, there were differences in total work between the Cr and placebo groups after (P ≤ 0.05) but not before the 14 d supplementation period. CONCLUSION: There is substantial evidence to indicate that a low-dose, short-term oral Cr supplementation beneficially affected muscle power output in elite youth soccer players.

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BACKGROUND: The aim of this study was to examine the relationship between repeated sprint ability (RSA, 6×40 m [20+20 m] with 20-s recovery) and neuromuscular and aerobic fitness variables in male collegiate soccer players. METHODS: Twenty-six players (age 22.5±3.6 years) were tested on separate days for countermovement jump (CMJ), squat jump (SJ), and standing long jump (LJ), and for maximal oxygen consumption (V̇O2max), velocity at onset of blood lactate accumulation (vOBLA), maximal aerobic speed (vV̇O2max), and peak blood lactate concentration (peak [La]). They were also tested for best and mean times on a repeated shuttle sprint ability test. RESULTS: RSA best time (r=-0.73 and r=-0.54) and RSA mean sprint time (r=-0.69 and r=-0.62) were significantly (P<0.01) correlated with LJ and CMJ, respectively. Significant correlations (P<0.05) were also found between RSA mean sprint time and sprint decrement with vOBLA (r=-0.44) and peak [La] (r=0.47), respectively. CONCLUSIONS: This study showed that RSA performance had a large to very large association with the individual level of jump performance and to a smaller extent to aerobic fitness variables in male collegiate soccer players. Given this finding, lower limbs' explosive-strength performance should be regarded as a relevant factor for male soccer.

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Using functional near-infrared spectroscopy, the present study investigated how listening to differently valenced music is associated with changes in hemoglobin concentrations in the prefrontal cortex area, indicating changes in neural activity. Thirty healthy people (15 men; M age = 24.8 yr., SD = 2.4; 15 women; M age = 25.2 yr., SD = 3.1) participated. Prefrontal cortex activation, emotional responses (heart rate variability), and self-reported affective ratings were measured while listening to calm and motivational music. The songs were presented in a random counterbalanced order and separated by periods of white noise. Mixed-model repeated-measures analysis of variance (ANOVA) evaluated the relationships for main effects and interactions. The results showed that music was associated with increased activation of the prefrontal cortex area. For both sexes, listening to the motivational song was associated with higher vagal withdrawal (lower HR) than the calm song. As expected, participants rated the motivational song with greater affective valence and higher arousal. Effects persisted longer in men than in women. These findings suggest that both the characteristics of music and sex differences may significantly affect the results of emotional neuroimaging in samples of young adults.

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This research investigated the effects of music and its time of application on a 5-km run. Fifteen well-trained male long-distance runners (24.87 ± 2.47 years; 78.87 ± 10.57 kg; 178 ± 07 cm) participated in this study. Five randomized experimental conditions during a 5-km run on an official track were tested (PM: motivational songs, applied before 5 km of running; SM: slow motivational songs, applied during 5 km of running; FM: fast and motivational songs, applied during 5 km of running; CS: calm songs, applied after 5 km of running; CO: control condition). Psychophysiological assessments were performed before (functional near-infrared spectroscopy, heart rate variability [HRV], valence, and arousal), during (performance time, heart rate, and rate of perceived exertion [RPE]), and after (mood, RPE, and HRV) tests. The chosen songs were considered pleasurable and capable of activating. Furthermore, they activated the 3 assessed prefrontal cortex (PFC) areas (medial, right dorsolateral, and left dorsolateral) similarly, generating positive emotional consequences by autonomous system analysis. The first 800 m was accomplished faster for SM and FM compared with other conditions (p ≤ 0.05); moreover, there was a high probability of improving running performance when music was applied (SM: 89%; FM: 85%; PM: 39%). Finally, music was capable of accelerating vagal tonus after 5 km of running with CS (p ≤ 0.05). In conclusion, music was able to activate the PFC area, minimize perceptions, improve performance, and accelerate recovery during 5 km of running.

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The rating of perceived exertion (RPE) is ability to detect and interpret organic sensations while performing exercises. This method has been used to measure the level of effort that is felt during weight-training at a given intensity. The purpose of this investigation was to compare session RPE values with those of traditional RPE measurements for different weight-training muscle actions, performed together or separately. Fourteen women with no former weight-training experience were recruited for the investigation. All participants completed five sessions of exercise: familiarization, maximum force, concentric-only (CONC-only), eccentric-only (ECC-only), and dynamic (DYN = CONC + ECC). The traditional RPE method was measured after each series of exercises, and the session RPE was measured 30 min after the end of the training session. The statistical analyses used were the paired t-test, one-way analysis of variance, and repeated measures analysis of variance. Significant differences between traditional RPE and session RPE for DYN, CONC, and ECC exercises were not found. This investigation demonstrated that session RPE is similar to traditional RPE in terms of weight-training involving concentric, eccentric, or dynamic muscle exercises, and that it can be used to prescribe and monitor weight-training sessions in older subjects.

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The aim of this study was to compare acute affective responses at exercise intensities based on the ventilatory threshold between normal weight, overweight, and obese women. 66 sedentary women (22 in each Body Mass Index group) performed a maximal graded treadmill test to measure their maximal oxygen uptake and ventilatory thresholds. Affective valence was compared at intensities spanning the ventilatory threshold (below, at, and above threshold). Affective valence below ventilatory threshold did not differ among the Body Mass Index groups. The obese group had a lower affective response at ventilatory threshold and above ventilatory threshold than the normal weight and overweight groups; the latter two groups did not differ. The obese group had a lower affective response than the normal and overweight groups, which corresponds to a less pleasant experience. Exercise prescriptions for obese subjects targeting intensities below ventilatory threshold can provide a more pleasant experience and may facilitate exercise adherence.

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The aim of this study was to investigate gender-based differences in substrate use during exercise at a self-selected pace. Seventeen men and 17 women performed a maximal exercise test and a 20-minute bout of self-paced treadmill walking to determine carbohydrate and fat oxidation rates. Gas exchange measurements were performed throughout the tests, and stoichiometric equations were used to calculate substrate oxidation rates. For each individual, a best-fit polynomial curve was constructed using fat oxidation rate (g·min(-1)) vs. exercise intensity (percentage of maximal oxygen uptake, % VO(2)max). Each individual curve was used to obtain the following variables: maximal fat oxidation (MFO), the peak rate of fat oxidation measured over the entire range of exercise intensities; fat(max), the exercise intensity at which the MFO was observed; and fat(max) zone, range of exercise intensities with fat oxidation rates within 10% of fat oxidation rates at fat(max). Although the MFO was similar between genders, fat(max) was lower in men than in women. Similarly, the "low" and "high" borders of the fat(max) zone were lower in men than in women. During exercise at a self-selected pace, carbohydrate oxidation rates were greater in men than in women, despite no gender-based differences in fat oxidation rates. However, fat oxidation contribution to total energy expenditure (EE) was greater in women than in men, despite no gender-based differences in the exercise intensity. In conclusion, although both genders self-selected a similar exercise intensity, the contribution of fat oxidation to EE is greater in women than in men. Interestingly, both genders self-selected an exercise intensity that falls within the fat(max) zone.

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UNLABELLED: Speculation exists that a positive affective response experienced during exercise may play an important role in predicting exercise adherence. Previous studies using self-paced exercise protocols have been associated with health benefits and pleasant experiences. However, all of these studies were conducted in laboratories, and consequently, the external validity of the findings may be questionable. PURPOSE: To determine whether environmental settings (treadmill vs overground) differentially influence physiological, perceptual, and affective responses to exercise at a self-selected pace. METHODS: Thirty-four individuals (17 men and 17 women) between 18 and 30 yr volunteered to participate in this study. During the orientation session, individuals underwent an initial screening, anthropometric measurements, and familiarization with the experimental procedures. Next, subjects underwent a maximal treadmill test. In the two experimental trials, participants performed 20-min bouts of treadmill and overground walking at a self-selected pace, which were completed in a counterbalanced order. At least 48 h separated experimental trials. RESULTS: Using repeated-measures ANOVA, overground walking speed was significantly faster than treadmill walking speed (P < 0.01) during the 20-min bout of self-paced exercise. However, exercise intensity (%VO2R and %HRR) and perceived exertion during the session of overground walking were significantly lower (P < 0.05) when compared with those during the treadmill session. In addition, affective valence was more positive during the session of overground walking than during the treadmill session (P < 0.01). CONCLUSIONS: These data extend previous findings by showing that environmental setting influences physiological, perceptual, and affective responses during exercise at a self-selected pace. Self-paced exercise performed over ground resulted in lower perceptual and more positive affective responses.

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O objetivo do presente estudo foi comparar as respostas fisiológicas e perceptuais entre os sexos durante a caminhada na esteira em ritmo autosselecionado. Participaram 17 homens e 17 mulheres, fisicamente ativos, com média de idade de 23,32 ± 3,06 anos, submetidos a duas sessões experimentais: (I) avaliação antropométrica e teste incremental máximo, e (II) um teste de 20 minutos de caminhada na esteira em ritmo autosselecionado. Para a análise estatística, empregou-se teste t de Student para medidas independentes no intuito de verificar as possíveis diferenças entre os sexos, adotando p < 0,05. A velocidade de caminhada autosselecionada pela amostra masculina foi superior à verificada na feminina (1,65 ± 0,18 e 1,50 ± 0,12m·seg-1, respectivamente) o que consequentemente resultou em maior O2 absoluto nos homens comparado às mulheres (21,2 ± 5,5 e 18,3 ± 2,7, respectivamente). No entanto, ambos os sexos buscaram caminhar em mesma intensidade relativa % O2máx, (37,5 ± 10,7 homens e 40,3 ± 7,2 mulheres). Em relação à percepção subjetiva de esforço (PSE), podemos verificar que ambos os sexos não demonstraram diferenças significativas (10,2 ± 1,0 homens e 9,8 ± 1,2 mulheres). Os achados do presente estudo demonstram que, independente do sexo, jovens adultos fisicamente ativos autosselecionaram similar intensidade relativa que refletiu em similar PSE. Além disso, a caminhada em intensidade autosselecionada demonstra-se como estímulo insuficiente para proporcionar melhora no condicionamento cardiorrespiratório nesta população.

The aim of this study was to compare physiological and perception responses between genders during treadmill walking at self-selected pace. 17 men and 17 women aged 23.32 ± 3.06 yr were investigated: (I) anthropometric assessment and incremental exhaustion test, (II) a 20-minute walking bout on treadmill at their self-selected pace. The independent t test was utilized to verify any gender differences, with a level of p < 0.05. The self-selected walking pace was significantly greater in men than women (1.65 ± 0.18 and 1.50 ± 0.12 m·sec-1, respectively), and consequently resulted in higher absolute VO2 for men compared to women (21.2 ± 5.5 and 18.3 ± 2.7, respectively). However, both genders self-selected a similar relative exercise intensity %VO2max (37.5 ± 10.7 and 40.3 ± 7.2 for men and women, respectively). The subjective perceived exertion (SPE) did not differ between genders (10.2 ± 1.0 and 9.8 ± 1.2 for men and women, respectively). The results of the present study demonstrated that regardless of gender, physically active young adults self-selected a similar relative exercise intensity that reflected in similar SPE. Furthermore, gait at self-selected intensity was insufficient to improve cardiorespiratory fitness in this sample.

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As respostas fisiológicas e perceptuais verificadas durante a caminhada vêm sendo amplamente pesquisadas; contudo, poucas investigações buscaram comparar essas respostas em grupos de diferentes índices de massa corporal durante caminhada em ritmo autosselecionado. O objetivo do presente estudo foi comparar as respostas fisiológicas e perceptuais entre mulheres com peso normal (PN), sobrepeso (SP) e obesas (OB) durante a caminhada em ritmo autosselecionado. Participaram 66 mulheres sedentárias, com idade entre 20 e 45 anos, designadas em três grupos de acordo com o seu índice de massa corporal: (i) PN (18,5 - 24,9kg·m-2, n = 22); (ii) SP (25,0 - 29,9kg·m-2, n = 22); e (iii) OB (> 30,0kg·m-2, n = 22). Cada participante realizou uma sessão de familiarização e duas sessões experimentais (teste incremental máximo e teste de 20 minutos de caminhada em ritmo autosselecionado), a fim de determinar as respostas fisiológicas (frequência cardíaca, FC; e consumo de oxigênio, VO2) e perceptuais (percepção subjetiva de esforço, PSE) de cada sessão. A ANOVA one-way foi empregada para comparar as respostas fisiológicas e perceptuais obtidas durante a caminhada em ritmo autosselecionado entre os três protocolos experimentais, empregando-se o teste post hoc de Tukey com p < 0,05. Embora os sujeitos com obesidade tenham registrado menor velocidade de caminhada (1,30 ± 0,13m·s-1) comparativamente aos com peso normal e sobrepeso (1,69 ± 0,11 e 1,58 ± 0,22m·s-1, respectivamente) (p < 0,05), eles apresentaram similar resposta fisiológica (58,7 ± 8,6; 63,1 ± 12,6; 64,8 ± 11,1 por centoVO2 e 75,1 ± 7,8; 78,8 ± 8,5; 78,7 ± 7,2 por centoFCmax, para os grupos normal, sobrepeso e obeso, respectivamente). Além disso, as respostas perceptuais também não diferiram entre os grupos experimentais (11,6 ± 1,6; 11,7 ± 1,6; 12,2 ± 1,8, respectivamente). Desse modo, pode-se concluir que, independente do IMC, mulheres adultas apresentam respostas fisiológicas e perceptuais ...

Physiological and perceived responses verified during gait have been widely studied; however, few investigations have tried to compare these responses in groups of different body mass indices during gait in self-selected rhythm. The aim of the present study was to compare the physiological and perceived responses among normative (N), overweighed (OW) and obese (OB) women during gait in self-selected rhythm. Sixty-six sedentary women, aged between 20 and 45 years and divided in three groups according to their body mass indices participated in the study: (i) N (18.5 - 24.9kg·m-2, n = 22); (ii) OW (25.0 - 29.9kg·m-2, n = 22) and (iii) OB (> 30.0kg·m-2, n = 22). Each participant performed a familiarization session and two experimental sessions (maximal incremental test and 20m-walking test in self-selected rhythm) to determine the physiological (heart rate - HR and oxygen consumption - O2) and perceived responses (perceived exertion - PE) of each session. One-way ANOVA was applied to compare the physiological and perceived responses obtained during gait in self-selected rhythm among the three experimental protocols, applying the Tukey's post hoc test with p < 0.05. Although the obese subjects have registered lower walking velocity (1.30 ± 0.13m·s-1) compared with the normative and overweighed ones (1.69 ± 0.11 and 1.58 ± 0.22m·s-1, respectively) (p < 0.05), they presented similar physiological response ((58.7 ± 8.6; 63.1 ± 12.6; 64.8 ± 11.1 percentO2 and 75.1 ± 7.8; 78.8 ± 8.5; 78.7 ± 7.2 percentHRmax, for the normative, overweighed and obese groups, respectively). Moreover, the perceived responses did not differ between experimental groups (11.6 ± 1.6; 11.7 ± 1.6; 12.2 ± 1.8, respectively). Therefore, it can be concluded that regardless of the BMI, adult women present similar physiological and perceived responses during gait in self-selected rhythm even when walking in different velocities.

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O objetivo do presente estudo foi comparar o O2Máx, FCMáx, %FCR, % O2R e METs entre os gêneros durante a caminhada em ritmo autosselecionado e verificar se a intensidade selecionada apresenta-se fisiologicamente efetiva para manutenção ou melhora da aptidão cardiorrespiratória (ACR). Participaram 17 homens e 17 mulheres com média de idade de 23,32 ± 3,06 anos, submetidos: (I) avaliação antropométrica e teste incremental máximo em esteira, (II) um teste de 20-minutos de caminhada em ritmo autosselecionado. Na análise estatística, empregou-se um teste t Student para medidas independentes, adotandop<0,05. Nenhuma diferença significativa entre os gêneros para o %FCMáx (58,38 ± 8,86 para homens e 62,12 ± 5,91 para mulheres), %VO2Máx (37,54 ± 10,75 para homens e 40,34 ± 7,27 para mulheres), %FCR (36,83 ± 11,77 para homens e 38,46 ± 8,33 para mulheres) e % O2R (31,88 ± 11,17 para homens e 34,70 ± 7,74 para mulheres). Entretanto, verifica-se quea velocidade de caminhada (km.h-1) selecionada foi superior no grupo masculino (5,96 ± 0,66; p<0,001) comparado ao feminino (5,41 ± 0,46), o que, possivelmente, propiciou que os METs fossem maiores nos homens (6,07 ± 1,57, p<0,05) comparado as mulheres (5,23 ± 0,77). Conclui-se que ambos os gêneros autosselecionam um ritmo de caminhada considerado não efetivo para manutenção e melhora da ACR, contudo, os valores de METs demonstram-se dentro do indicado para manutenção e redução do peso corporal. As diferenças encontradas entre os gêneros para o METs podem ser decorrentes das diferenças apresentadas para a velocidade de caminhada e características antropométricas.

The objective of this study was to compare % O2Max, %HRMax, %HRR, % O2R, and MET between genders during walking at a self-selected pace and to determine whether the self-selected pace was physiologically effective in maintaining and improving cardiorespiratory fitness. Seventeen men (age: 24.05 ± 3.3 years) and 17 women (age> 22.58 ± 2.67 years)were submitted to two experimental sessions: (I) anthropometric assessment and incremental exhaustion test, and (II) 20-min treadmill walking bouts at a self-selected pace. The independent Student t-test was used to determine differences between genders, at an alpha level of 0.05. No significant differences in %HRMax (58.38 ± 8.86 for men and 62.12 ± 5.91 for women), % O2Max (37.54 ± 10.75 for men and 40.34 ± 7.27 for women), %HRR (36.83 ± 11.77 for men and 38.46 ± 8.33 for women), or % O2R (31.88 ± 11.17 for men and 34.70 ± 7.74 for women) wereobserved between genders. However, the walking speed selected (km.h-1) was higher in men (5.96 ± 0.66, p<0.001) than women, a finding that probably resulted in higher MET values for men (6.07 ± 1.57, p<0.05) compared to women (5.23 ± 0.77). In conclusion, both genders selected a walking pace that was not effective in maintaining or improving cardiorespiratory fitness, but MET values were within the range indicated for the maintenance and reduction of body weight. The differences in METs observed between genders might be due to differences in walking speedand anthropometric characteristics.