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This study aimed to compare the intensity of deoxygenated haemoglobin concentration ([HHb]) and tissue saturation index (TSI) breakpoints ([HHb]-BP and TSI-BP) with maximal lactate steady state (MLSS) and critical power (CP), and to describe their association with 2000-m rowing ergometer performance. Fourteen male rowers performed on a rowing ergometer: I) a discontinuous incremental test with 3-min stages (INC3); II) a continuous incremental test with 1-min stages (INC1); III) constant workload tests to determine MLSS; and IV) performance tests of 500 m, 1000 m, 2000 m and 6000 m to determine CP.CP (257 ± 39 W; 3.79 ± 4.1 L · min-1) was higher than [HHb]-BP3 (205 ± 26 W; 3.48 ± 2.9 L · min-1), [HHb]-BP1 (207 ± 27 W; 3.27 ± 3.2 L · min-1), and TSI-BP3 (218 ± 31 W; 3.51 ± 3.0 L · min-1), but not higher than TSI-BP1 (222 ± 34 W; 3.43 ± 3.2 L · min-1). MLSS (187 ± 26 W; 3.33 ± 3.2 L · min-1) was lower than TSI-BP3 and TSI-BP1 for power output, but not different in any comparison for ⩒O2. The limits of agreement for power output and ⩒O2 suggest poor agreement among these thresholds. The low level of agreement compromises the use of [HHb]-BP and TSI-BP for estimating MLSS and CP; therefore, these thresholds should not be considered interchangeable.

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BACKGROUND: Cardiovascular diseases are a leading cause of mortality worldwide. A significant contributing factor to this mortality is the lack of engagement in preventive activities. Consequently, strategies for enhancing adherence to and duration of physical activity (PA) have become pivotal. This project aims to create and validate innovative, disruptive, and secure technologies that ensure appropriate exercise intensity, bolster adherence to PA, and monitor health biomarker responses pre-, during, and post-physical activity. METHODS: This exploratory study, followed by a noninferiority, investigator-blinded randomized clinical trial, will be divided into three phases: (1) development and validation of a sensor for real-time biofeedback during a functional assessment test; (2) integration of biofeedback and gamification into an app for the structured prescription of physical training within a controlled setting; and (3) implementation of biofeedback and gamification into an app for the prescription and monitoring of physical training in an uncontrolled setting. Phase 1 entails a validation test of a biosensor-monitoring heart rate (HR) and steps-during a modified shuttle walk test. In phase 2, the biosensor interfaces with a gamified smartphone application. The training regimen spans 6 weeks, 5 days weekly, with each session lasting 60 min: a five-min warm-up involving stationary gait, followed by 50 min of training at the target HR on the step and concluding with a five-min cool-down at a stationary pace. After 6 weeks of training, a new functional capacity test is conducted. Phase 3 involves an investigator-blinded, randomized clinical trial to demonstrate noninferiority. Participants are randomly assigned to either the intervention group (IG) or the control group (CG). IG participants practice exercise using the gamified application in an uncontrolled environment according to the prescribed method outlined in phase 2. CG participants receive PA practice guidelines exclusively. DISCUSSION: Anticipated outcomes include improved exercise adherence through the gamified application, better maintenance of prescribed exercise intensity, and enhanced health biomarkers. The results of this study will inform health-related decision-making. TRIAL REGISTRATION: The study protocol received approval from the Ethics Committee of Universidade Federal de Ciências da Saúde de Porto Alegre (54,492,221.80000.5345) and has been registered with the Brazilian Registry of Clinical Trials (ReBEC, RBR-359p69v).

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Understanding the frequency, duration, and intensity of exercise is important for determining the optimal diet and management of horses. The objective of the study was to characterize the exercise management of horses in Pennsylvania. An online survey was distributed from February 27th to August 31st, 2020. Respondents were asked to place their horse in an exercise category, as well as report on frequency and duration of exercise and time spent at each gait. Nonparametric statistics (mdn=median) and tests were used when data were not normally distributed. Of the 470 horses, 68% were regularly exercised. The exercised horses were classified as 49% (135/275) in light, 41% (113/275) in moderate, and 12% (32/275) in heavy/very heavy exercise. Of those exercised, 43% (120/278) were ridden recreationally (not used for competition). The median minutes per week spent exercising was 180 minutes (IQR=183). The average number of exercise sessions per week was 3.6 ± 2.2. Horses in heavy/very heavy (mdn=220 min, IQR=272) and moderate exercise (mdn=180 min, IQR=180) spent more minutes exercising per week compared to light exercise (mdn=120 minute, IQR=180; P< .05). Total number of exercise sessions completed per week differed between horses in light (mdn=2 sessions, IQR=3), moderate (mdn=4 sessions, IQR=2), and heavy/very heavy exercise (mdn=6 sessions, IQR=2; P < .05). Horses were exercised for a similar duration and frequency per week compared to previous studies. Some challenges exist for placing horses in NRC exercise categories based on self-reports only.

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Abstract This study aimed to compare the effects of diet and exercise of different intensities on antioxidant function, aortic endothelial cell function and serum lipids in NAFLD (nonalcoholic fatty liver disease) rats. Fifty Sprague-Dawley (SD) rats (180-220g) were randomly divided into two experimental groups and fed either a standard rodent chow diet (CON; n=10) or a high-fat diet (HFD; n=40). After 16 weeks, the animals that received the HFD were randomly separated into a high-fat control group (HFC; n=10) or three exercise training groups: HFD and low-intensity exercise (LE; n=10), HFD and moderate-intensity exercise (ME; n=10), and HFD and incremental intensity exercise (IE; n=10). These experimental rats keep sedentary or trained for the next six weeks. A detection kit was used to detect nitric oxide synthase (NOs), nitric oxide (NO), malondialdehyde (MDA) and other markers of aortic oxidative stress. The expression levels of endothelial nitric oxide synthase (e-NOS) and endothelin-1 (ET-1) were detected by immunohistochemistry. TC, TG, and other lipid metabolism parameters were detected by an automatic analyzer. Exercise with different intensities could improve lipid metabolism, enhance antioxidant function, reduce MDA (P<0.01), increase NO (P<0.01), and improve the expression of e-NOS and ET-1 (P<0.01) protein levels in NAFLD rats. Decreased blood lipids were exhibited in all exercise groups. Notably, the moderate-intensity exercise demonstrated more effect on increasing glutathione (GSH) contents (P<0.01) and decreased the expression of ET-1 protein levels (P<0.01). The results showed that exercise at different intensities improved lipid metabolism and enhanced anti-oxidation function. Moderate exercise could improve the function of aortic endothelial cells.

Resumen Este estudio tuvo como objetivo comparar los efectos de la dieta y el ejercicio a diferentes intensidades sobre la función antioxidante, la función de las células endoteliales aórticas y los lípidos séricos en ratas NAFLD (con enfermedad del hígado graso no alcohólico) y alimentados con una dieta estándar para roedores (CON; n = 10) o con una dieta alta en grasas (HFD; n = 40). Después de 16 semanas, los animales que recibieron HFD se separaron aleatoriamente en un grupo de control alto en grasas (HFC; n=10) o tres grupos de entrenamiento físico: HFD y ejercicio de baja intensidad (LE; n=10), HFD y ejercicio de intensidad moderada (ME; n=10), y HFD y ejercicio de intensidad incremental (IE; n=10). Estas ratas experimentales se mantuvieron sedentarias o entrenadas durante las próximas seis semanas. Se utilizó un kit de detección para determinar óxido nítrico sintetasa (NO), óxido nítrico (NO), malondialdehído (MDA) y otros marcadores de estrés oxidativo aórtico. Los niveles de expresión de la óxido nítrico sintetasa endotelial (e-NOS) y endotelina-1 (ET-1) se detectaron mediante inmunohistoquímica. El analizador automático detectó TC, TG y otros parámetros del metabolismo de los lípidos. El ejercicio con diferente intensidad mejoró el metabolismo de los lípidos, mejoró la función antioxidante, redujo la MDA (P <0,01), aumentó el NO (P <0,01) y mejoró la expresión de los niveles de proteína e-NOS y ET-1 (P <0,01) en ratas NAFLD. Se observó una disminución de los lípidos en sangre en todos los grupos de ejercicio. En particular, el ejercicio de intensidad moderada demostró un mayor efecto en el aumento del contenido de glutatión (GSH) (P<0,01) y disminuyó la expresión de los niveles de proteína ET-1 (P<0,01). Los resultados mostraron que el ejercicio a diferentes intensidades mejoró el metabolismo de los lípidos y mejoró función antioxidante. El ejercicio moderado podría mejorar la función de las células endoteliales aórticas.

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The aim of this study was threefold: (a) to compare the maximal lactate steady state (MLSS) with critical power (CP); (b) to describe the relationship of MLSS with rowing performances; and (c) to verify the agreement of MLSS with several exercise intensity thresholds in rowers. Fourteen male rowers (mean [SD]: age = 26 [13] years; height = 1.82 [0.05] m; body mass = 81.0 [7.6] kg) performed on a rowing ergometer: (I) discontinuous incremental test with 3 min stages and 30-s recovery intervals (INC3min); (II) continuous incremental test with 60-s stages (INC1min); (III) two to four constant workload tests to determine MLSS; and (IV) performance tests of 500, 1000, 2000 and 6000 m to determine CP. Twenty-seven exercise intensity thresholds based on blood lactate, heart rate and ventilatory responses were determined by incremental tests, and then compared with MLSS. CP (257 [38] W) was higher than MLSS (187 [25] W; p < 0.001), with a very large mean difference (37%), large typical error of estimate (14%) and moderate correlation (r = 0.48). Despite the correlations between MLSS and most intensity thresholds (r > 0.70), all presented low correspondence (TEE > 5%), with a lower bias found between MLSS and the first intensity thresholds (-12.5% to 4.1%). MLSS was correlated with mean power during 500 m (r = 0.65), 1000 m (r = 0.86) and 2000 m (r = 0.78). In conclusion, MLSS intensity is substantially lower than CP and presented low agreement with 27 incremental-derived thresholds, questioning their use to estimate MLSS during rowing ergometer exercise.Highlights MLSS was substantially lower than CP in rowing exercise with a mean difference of 37%, much larger than the difference commonly found in running and cycling exercise (i.e., ?10%).A clear disagreement was reported between MLSS and 27 physiological thresholds determined in different incremental tests.There is a positive association of MLSS with 500, 1000 and 2000 m rowing ergometer performance tests.

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There is a high incidence of non-obese type 2 diabetes mellitus (non-obese-T2DM) cases, particularly in Asian countries, for which the pathogenesis remains mainly unclear. Interestingly, Goto-Kakizaki (GK) rats spontaneously develop insulin resistance (IR) and non-obese-T2DM, making them a lean diabetes model. Physical exercise is a non-pharmacological therapeutic approach to reduce adipose tissue mass, improving peripheral IR, glycemic control, and quality of life in obese animals or humans with T2DM. In this narrative review, we selected and analyzed the published literature on the effects of physical exercise on the metabolic features associated with non-obese-T2DM. Only randomized controlled trials with regular physical exercise training, freely executed physical activity, or skeletal muscle stimulation protocols in GK rats published after 2008 were included. The results indicated that exercise reduces plasma insulin levels, increases skeletal muscle glycogen content, improves exercise tolerance, protects renal and myocardial function, and enhances blood oxygen flow in GK rats.

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ABSTRACT This study aimed to verify the effect of exercise recovery time on the affective responses during a circuit training in physical education classes. Forty-six apparently healthy young adolescents (twenty-one girls) (12.85 ± 0.94 years; 49.7 ± 8.93 kg; 1.59 ± 0.08 cm; 19.51 ± 3.28 kg/m2) participated in this study. Were submitted participants for two physical education classes, based on circuited model of the same intensity, but with different recovery times (2 min and 1 min). The study was carried out in two phases: baseline and intervention. Affect, Arousal, and Ratings of Perceived Exertion data were analyzed using paired t-tests, considering a significance level of p < 0.05. The class with longer rest time (2 min) provided greater affection (t(45) = 3.586; p < 0,001) and less perceived effort (t(45) = 2.295; p = 0,026). The intensity manipulation strategy was effective in providing different affective responses, in which classes perceived as more intense, resulting in the decline of affect.

RESUMO O objetivo do estudo foi verificar o efeito do tempo de recuperação do exercício nas respostas afetivas durante um treinamento em circuito nas aulas de educação física. Quarenta e seis jovens adolescentes aparentemente saudáveis (vinte e uma meninas), com (12.85 ± 0.94 anos; 49.7 ± 8.93 kg; 1.59 ± 0.08 cm; 19.51 ± 3.28 kg/m2), participaram do estudo. Os participantes foram submetidos a duas aulas de educação física escolar, baseados em modelo de circuitos de mesma intensidade, porém com tempos de recuperação diferentes (2 min e 1 min). O estudo foi realizado em duas fases: base e intervenção. Os dados de Afeto, Ativação e Percepção Subjetiva do Esforço, foram analisados através de testes t pareados, considerando um nível de significância de p < 0,05. A aula com maior tempo de descanso (2 min) proporcionou maior afeto (t(45) = 3.586; p < 0,001) e menor esforço percebido (t(45) = 2.295; p = 0,026). A estratégia de manipulação da intensidade foi efetiva para proporcionar respostas afetivas diferentes, em que a aula percebida como mais intensa resultou no declínio do afeto.

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There is a high incidence of non-obese type 2 diabetes mellitus (non-obese-T2DM) cases, particularly in Asian countries, for which the pathogenesis remains mainly unclear. Interestingly, Goto-Kakizaki (GK) rats spontaneously develop insulin resistance (IR) and non-obese-T2DM, making them a lean diabetes model. Physical exercise is a non-pharmacological therapeutic approach to reduce adipose tissue mass, improving peripheral IR, glycemic control, and quality of life in obese animals or humans with T2DM. In this narrative review, we selected and analyzed the published literature on the effects of physical exercise on the metabolic features associated with non-obese-T2DM. Only randomized controlled trials with regular physical exercise training, freely executed physical activity, or skeletal muscle stimulation protocols in GK rats published after 2008 were included. The results indicated that exercise reduces plasma insulin levels, increases skeletal muscle glycogen content, improves exercise tolerance, protects renal and myocardial function, and enhances blood oxygen flow in GK rats

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BACKGROUND: Dancing has been suggested to increase the levels of physical activity of the youth. However, it is not clear what are the physiological characteristics of the dance classes for young people, mainly regarding the levels of moderate to vigorous physical activity (MVPA) during classes. It is also unclear if regular engagement in dance practices can contribute with increases in the amounts of daily/weekly MVPA, recommended by health organizations. OBJECTIVES: To conduct a systematic review verifying the amount of time spent at MVPA (primary outcome), by children and adolescents in the following situations: i) During dance classes, and ii) Before and after dance interventions. Secondary outcomes included: markers of exercise intensity during class, such as oxygen consumption (VO2) and heart rate (HR); VO2peak and lipid profile before and after dance interventions. METHODS: Six data sources were accessed (MEDLINE, EMBASE, Cochrane Wiley, PEDRO and SCOPUS). Study selection included different designs (acute, cohort, randomized controlled trials and others). Participants were from 6 to 19 years old, regularly engaged in dance practices. Methodological quality was assessed using the Downs and Black checklist. Two independent reviewers extracted characteristics and results of each study. RESULTS: 3216 articles were retrieved, and 37 included. Studies indicated that dance classes do not achieve 50% of total class time at MVPA. However, there are peaks of HR and VO2 during dance classes, which reach moderate and vigorous intensities. MVPA/daily/weekly did not improve before and after dance interventions for most of the studies, also VO2peak did not. The few results on lipid profile showed improvements only in overweight and obese participants. LIMITATIONS: Lack of meta-analysis, because there were not enough articles to be analyzed on any given outcome of interest, neither under the same study design. CONCLUSIONS: Results of individual studies indicated that dance classes did not active 50% of the total time at MVPA levels. This may be related to the absence of improvements in daily/weekly MVPA before and after dance interventions. VO2 and HR attained peaks of moderateto vigorous intensity during dance classes, suggesting that the structure of the classes may be manipulated to maintain longer periods at MVPA levels. Lack of data on cardiorespiratory fitness and metabolic outcomes limit conclusions on these parameters. IMPLICATIONS OF KEYS FINDS: Considering there are peaks of HR and VO2 during dance classes, we suggest that the structure of a dance class can be manipulate in order to induce cardiorespiratory and metabolic adaptations. Thus, dancing is a potential strategy to contribute with a healthy life style since the earliest ages. Prospero registration: CRD42020144609.

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We assessed the reliability and validity of a 10-min submaximal treadmill test (T10) to predict critical speed (CS). Forty-two runners completed a familiarization trial plus two experimental trials (T10 test and T10 retest). Reliability between the T10 test and T10 retest was assessed using coefficient of variation (CoV), limits of agreement (LoA) and intraclass correlation (ICC). For validity, the speed from the T10 retest was compared with the CS determined from 3 runs on separate days on a running track over 1200, 2400, and 3600 m (field test). Reliability between the T10 test and T10 retest showed a CoV of 3.4%, LoA of 0.05 ± 0.39 m.s-1, and an ICC of 0.93. Validity showed that speed (m.s-1) (T10 retest: 3.86 ± 0.51; field test: 3.88 ± 0.55) did not differ between trials. The T10 retest was highly correlated with the field test, r = 0.93, and the standard error for the estimate of CS using the T10 retest was 0.06 m.s-1, and the LoA was 0.02 ± 0.40 m.s-1. A submaximal 10-min treadmill test (T10) provides a practical and accessible method to estimate CS.

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AIMS: The aim of this study was to analyze the acute effects of Heart Rate (HR) and Rating of Perceived Exertion (RPE) for 21 of 34 original Mat Pilates (MP) exercises, to estimate maximum oxygen consumption (VO2max), and energy expenditure (EE) of a MP session. METHODS: Ten participants volunteered (26.30 ±â€¯3.98 yrs) to measure the intensity of each exercise; HR and RPE were monitored immediately after the end of each exercise. VO2maxwas estimated using the Astrand-Ryhming step submaximal test, and EE by a linear regression equation. HR and RPE mean values and standard deviations were calculated for each exercise. RESULTS: The maximum value for each participant normalized the EE and VO2max values, which were ranked from highest to lowest. The percentage of the mean values of HRmax and RPEmax in each exercise showed significant, strong and positive correlation (p = 0.82; p = 0.001). In 10 exercises, HR was 60% higher than HRmax. The mean values of EE and VO2max were 213.71 ±â€¯(76.41) Kcal and 34.69 ml (Kg.min)-1 (±3.5), respectively, for the entire MP session. Half of the exercises achieved moderate intensity in HR with low estimated VO2max during the whole MP session. However, if the MP session of this study was practiced five times per week, it would meet the weekly American College of Sports Medicine (ACSM) EE recommendations. CONCLUSION: The 21 MP exercises monitored in this study promote considerably acute and high increments in HR and RPE.

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Endurance running has become an immensely popular sporting activity, with millions of recreational runners around the world. Despite the great popularity of endurance running as a recreational activity during leisure time, there is no consensus on the best practice for recreational runners to effectively train to reach their individual objectives and improve physical performance in a healthy manner. Moreover, there are lots of anecdotal data without scientific support, while most scientific evidence on endurance running was developed from studies observing both recreational and professional athletes of different levels. Further, the transference of all this information to only recreational runners is difficult due to differences in the genetic predisposition for endurance running, the time available for training, and physical, psychological, and physiological characteristics. Therefore, the aim of this review is to present a selection of scientific evidence regarding endurance running to provide training guidelines to be used by recreational runners and their coaches. The review will focus on some key aspects of the training process, such as periodization, training methods and monitoring, performance prediction, running technique, and prevention and management of injuries associated with endurance running.

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Pacing during a high-intensity cycling time trial (TT) appears to prevent premature task failure, but the performance fatigability during a self-paced exercise is currently unknown. Therefore, the current study characterized the time course of performance fatigability during a 4-km TT. Eleven male cyclists performed three separated TTs in a crossover, counterbalanced design. The TTs lasted until the end of the fast-start (FS; 600 ± 205 m), even-pace (EP; 3,600 ± 190 m), and end-spurt (ES; 4,000 m) phases. Performance fatigability was characterized by using isometric maximal voluntary contractions (IMVCs), whereas the muscle activation [i.e., voluntary activation (VA)] and contractile function of knee extensors [e.g., peak torque of potentiated twitches (TwPt)] were evaluated using electrically evoked contractions performed before and 1 min after each specific part of the trial. Gas exchange, power output (PO), and electromyographic activity (EMG) were also recorded. EMG/PO showed an abrupt increase followed by a continuous decrease toward the end of FS, resulting in a drop in IMVC (-12%), VA (-8%), and TwPt (-23%). EMG/PO was stable during EP, with no additional drop on IMVC, VA, or TwPt (-12%, -6%, and -22%, respectively). EMG/PO increased abruptly during the ES, but there was no change in IMVCs, VA, or TwPt (-13%, -8%, and -26%, respectively). These findings demonstrate that the performance fatigability during a self-paced exercise is characterized by a large drop in contractile function and muscle activation at the beginning of the trial (i.e., FS), without additional change during the middle and end phases (i.e., EP and ES).NEW & NOTEWORTHY The time course of performance fatigability throughout a self-paced exercise is currently unknown. The results showed that a large amount of muscle activation and contractile function impairments are attained early on a self-paced exercise (first ∼15% of the total time trial distance) and maintained throughout the test. This novel finding characterizes the performance fatigability from a contractile function and muscle activation perspective, which brings new insights for future studies focused on real-world exercise training and competition.

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PURPOSE: The relationship between inflammatory markers and energetic metabolism has been explored. However, the relationship between exercise intensity and fitness status is unclear, and it is necessary to understand this relationship to apply specific exercise guidance. The purpose of the study was to analyze metabolic and inflammatory responses imposed by acute exercise sessions performed at moderate, heavy, and severe intensities and their relationship with the physical fitness status. METHODS: Nineteen healthy male volunteers performed three acute exercise sessions until exhaustion or up to 60 minutes on a cycle ergometer at moderate (90% of first ventilatory threshold [VT1]), heavy (midpoint between VT1 and second ventilatory threshold [VT2]), and severe (midpoint between VT2 and maximal aerobic power) intensities. Blood lactate, glucose, NEFA, endotoxin, and cytokines were determined for each exercise session. Peripheral and lipopolysaccharide (LPS)-stimulated release of tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and IL-10 was analyzed before, after, and 60 minutes after sessions. RESULTS: In peripheral blood, severe intensity increased lactate, endotoxin, and TNF-α immediately after exercise and glucose at 60 min after exercise. There was a trend for IL-10 increase at 60 minutes after exercise in peripheral blood. Immediately after exercise, LPS-stimulated TNF-α, IL-6, IL-6/IL-10 ratio, and lactate levels were higher in the severe intensity while nonester fatty acid levels decreased at this time. At 60 minute after exercise, higher concentrations of glucose and a trend for increased IL-10 were observed in severe intensity. A positive correlation was observed between maximal aerobic power and IL-10 ( r = 0.513; P = 0.042), and negative correlations between maximal aerobic power and endotoxin ( r = -0.531; P = 0.034) and lactate ( r = -0.538; P = 0.031) in heavy intensity. CONCLUSION: Our data show a novel finding that higher cytokine responses occur at higher intensities, mainly in severe intensity. However, the anti-inflammatory (IL-10) response was physical fitness-dependent.

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OBJECTIVES: To explore the impact of short-term exercise of varying intensity on traditional risk factors for cardiometabolic disease. STUDY DESIGN: A total of 109 children (mean age, 11.1 ± 0.8 years) were conveniently assigned to 5 weeks of moderate-intensity continuous training (MICT; n = 29) set at 65%-70% of maximum heart rate, high-intensity interval training (HIIT; n = 29; >80% maximum heart rate), combined training (HIIT + MICT; n = 27), or no training (control; n = 24). Two-way ANOVA (group × time) was used to evaluate the effects of training on all cardiometabolic disease risk factors. Effect sizes were calculated to assess the magnitude of difference. RESULTS: MICT, HIIT, and HIIT + MICT were associated with significantly improved resting heart rate (effect size, -0.4, -1.1, and -1.1, respectively; P < .0001), fasting glucose (effect size, -0.6, -0.9, and -0.1, respectively; P = .0004), peak oxygen consumption (effect size, 0.5, 0.9, and 0.5, respectively; P < .0001), and c-reactive protein (effect size, -0.2, -1.0, and -0.5, respectively; P = .0016). HIIT + MICT was significantly associated with reduced waist circumference (-5.4%; P < .0001) and waist-to-hip ratio (-2.5%; P < .0002) compared with MICT (7.0% and 6.3%, respectively) and HIIT (-0.5% and -1.3%, respectively). CONCLUSION: Short-term HIIT and MICT interventions are useful for improving cardiometabolic health in children. HIIT + MICT may provide superior reductions in central obesity indicators.

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BACKGROUND: There is evidence to suggest that postprandial lipemia are is linked to the impairment of endothelial function, which is characterized by an imbalance between the actions of vasodilators and vasoconstrictors. The aim of this study was to determine the effects of a 12-week high-intensity training (HIT) and moderate continuous training (MCT) protocol on postprandial lipemia, vascular function and arterial stiffness in inactive adults after high-fat meal (HFM) ingestion. METHODS: A randomized clinical trial was conducted in 20 healthy, inactive adults (31.6 ± 7.1 years). Participants followed the two exercise protocols for 12 weeks. To induce a state of postprandial lipemia (PPL), all subjects received a HFM. Endothelial function was measured using flow-mediated vasodilation (FMD), normalized brachial artery FMD (nFMD), aortic pulse wave velocity (PWV) and augmentation index (AIx). Plasma total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides and glucose were also measured. RESULTS: The effects of a HFM were evaluated in a fasted state and 60, 120, 180, and 240 min postprandially. A significant decrease in serum glucose between 0 min (fasted state) and 120 min postprandially was found in the HIT group (P = 0.035). Likewise, FMD (%) was significantly different between the fasted state and 60 min after a HFM in the HIT group (P = 0.042). The total cholesterol response expressed as area under curve (AUC)(0-240) was lower following HIT than following MCT, but no significant differences were observed (8%, P > 0.05). Similarly, triglycerides AUC(0-240) was also lower after HIT compared with MCT, which trended towards significance (24%, P = 0.076). The AUC(0-240) for the glucose response was significantly lower following HIT than MCT (10%, P = 0.008). FMD and nFMD AUC(0-240) were significantly higher following HIT than following MCT (46.9%, P = 0.021 and 67.3%, P = 0.009, respectively). PWV AUC(0-240) did not differ following between the two exercise groups (2.3%, P > 0.05). CONCLUSIONS: Supervised exercise training mitigates endothelial dysfunction and glucose response induced by PPL. Exercise intensity plays an important role in these protective effects, and medium-term HIT may be more effective than MCT in reducing postprandial glucose levels and attenuating vascular impairment. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02738385 Date of registration: April 14, 2016.

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The objective of this study was to test the hypotheses that end-test torque (ET) (expressed as % maximal voluntary contraction; MVC) is higher for plantar flexors (PF) than knee extensors (KE) muscles, whereas impulse above ET (IET) is higher for KE than PF. Thus, we expected that exercise tolerance would be longer for KE than PF only during the exercise performed above ET. After the determination of MVC, 40 men performed two 5-min all-out tests to determine ET and IET. Eleven participants performed a further 4 intermittent isometric tests, to exhaustion, at ET + 5% and ET - 5%, and 1 test for KE at the exercise intensity (%MVC) corresponding to ET + 5% of PF. The IET (7243.2 ± 1942.9 vs. 3357.4 ± 1132.3 N·m·s) and ET (84.4 ± 24.8 vs. 73.9 ± 19.5 N·m) were significantly lower in PF compared with KE. The exercise tolerance was significantly longer for PF (300.7 ± 156.7 s) than KE (156.7 ± 104.3 s) at similar %MVC (∼60%), and significantly shorter for PF (300.7 ± 156.7 s) than KE (697.0 ± 243.7 s) at ET + 5% condition. However, no significant difference was observed for ET - 5% condition (KE = 1030.2 ± 495.4 s vs. PF = 1028.3 ± 514.4 s). Thus, the limit of tolerance during submaximal isometric contractions is influenced by absolute MVC only during exercise performed above ET, which seems to be explained by differences on both ET (expressed as %MVC) and IET values.

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The aims of this study were: i) to verify whether player internal load (PIL) monitored via heart rate (HR) varies with game-time and playing position; ii) whether intermittent running capacity (IRC) is related to the maintenance of within-match PIL in elite youth (U-15) soccer players. Method: Twenty-one elite soccer players (14±0.5 yrs, 172±7 cm, 63±6 kg) had their heart rate monitored (beats/min) in five matches and were tested twice for IRC (Yo-YoIR2, distance [m]) over a seven-week competitive season. Percentage of maximal heart rate (%HRmax) and time spent (TS%) in five zones (Z1[<70%]; Z2[71-85%]; Z3[86-90%]; Z4[91-95%] and Z5[>96%]) were our PIL indexes. Data from three complete games in the same position of each player were analyzed and matches halves, time intervals (T1 to T6), and playing positions (fullbacks, central defenders and forwards [N=5 each], midfielders [N=6]) were compared, and the relationship between IRC and within-match PIL was determined. Results: PIL was higher in 1st (86±3%) than in the 2nd half (84±4%; p<.001). The 2nd half had more TS% in Z1 and Z2 (p<.05). PIL in T4 was the lowest (p<.01), and in T6, it was lower than T1 and T2 (p<.01). Fullbacks and midfielders showed higher PIL and higher TS% in Z4 (p<.05) than the other positional roles. The average IRC correlated with PIL in T6 (r=.56, p<.01) only. Conclusion: In conclusion, the internal load in elite youth (U-15) soccer players varies with game-time and playing position; and their IRC is related to the maintenance of within-match PIL.(AU)

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The present study attempts to assess changes in soccer players' physical activity profiles under the simultaneous influence of the different combinations of ambient temperature and relative humidity characterising matches of the 2014 FIFA World Cup hosted by Brazil. The study material consisted of observations of 340 players representing 32 national teams taking part in the tournament. The measured indices included total distances covered; distances covered with low, moderate, or high intensity; numbers of sprints performed, and peak running speeds achieved. The analysis was carried out using FIFA official match data from the Castrol Performance Index system. Ultimately, consideration was given to a combination of three air temperature ranges, i.e. below 22 °C, 22-28 °C, and above 28 °C; and two relative humidity ranges below 60 % and above 60 %. The greatest average distance recorded (10.54 ± 0.91 km) covered by players at an air temperature below 22 °C and a relative humidity below 60 %, while the shortest (9.83 ± 1.08 km) characterised the same air temperature range, but conditions of relative humidity above 60 % (p ≤ 0.001). Two-way ANOVA revealed significant differences (p ≤ 0.001) in numbers of sprints performed by players, depending on whether the air temperature range was below 22 °C (40.48 ± 11.17) or above 28 °C (30.72 ± 9.40), but only where the relative humidity was at the same time below 60 %. Results presented indicate that the conditions most comfortable for physical activity on the part of players occur at 22 °C, and with relative humidity under 60 %.

Assuntos

RESUMO

Although acute exercise is apparently pro-inflammatory and increases oxidative stress, it can promote the necessary stress stimulus to train chronic adaptations in patients with chronic heart failure (CHF). This study aimed to compare the effects of exercise intensity and duration on the inflammatory markers soluble tumor necrosis factor receptor (sTNFR1) and interleukin-6 (IL-6), and on oxidative stress [malondialdehyde (MDA) and antioxidant enzymes: catalase (CAT) and superoxide dismutase (SOD)] in individuals with CHF. Eighteen patients performed three exercise sessions: 30 min of moderate-intensity (M30) exercise, 30 min of low-intensity (L30) exercise, and 45 min of low-intensity (L45) exercise. Blood analysis was performed before exercise (baseline), immediately after each session (after), and 1 h after the end of each session (1h after). Thirty min of M30 exercise promoted a larger stressor stimulus, both pro-inflammatory and pro-oxidative, than that promoted by exercises L30 and L45. This was evidenced by increased sTNFR1 and MDA levels after exercise M30. In response to this stressor stimulus, 1 h after exercise, there was an increase in IL-6 and CAT levels, and a return of sTNFR1 to baseline levels. These findings suggest that compared with the duration of exercise, the exercise intensity was an important factor of physiologic adjustments.

Assuntos