Is melatonin as an ergogenic hormone a myth? a systematic review and meta-analysis.

PURPOSE: Melatonin supplementation has been disclosed as an ergogenic substance. However, the effectiveness of melatonin supplementation in healthy subjects has not been systematically investigated. The present study analyzed the effects of melatonin supplementation on physical performance and recovery. In addition, it was investigated whether exercise bout or training alter melatonin secretion in athletes and exercise practitioners. METHODS: This systematic review and meta-analysis were conducted and reported according to the guidelines outlined in the PRISMA statement. Based on the search and inclusion criteria, 21 studies were included in the systematic review, and 19 were included in the meta-analysis. RESULTS: Melatonin supplementation did not affect aerobic performance relative to time trial (-0.04; 95% CI: -0.51 to 0.44) and relative to VO2 (0.00; 95% CI: -0.57 to 0.57). Also, melatonin supplementation did not affect strength performance (0.19; 95% CI: -0.28 to 0.65). Only Glutathione Peroxidase (GPx) secretion increased after melatonin supplementation (1.40; 95% CI: 0.29 to 2.51). Post-exercise melatonin secretion was not changed immediately after an exercise session (0.56; 95% CI: -0.29 to 1.41) and 60 min after exercise (0.56; 95% CI: -0.29 to 1.41). CONCLUSION: The data indicate that melatonin is not an ergogenic hormone. In contrast, melatonin supplementation improves post-exercise recovery, even without altering its secretion.

Anthropometric profile at u-15 to professional on brazilian national team soccer players / Perfil antropométrico de jugadores sub-15 a profesionales de la selección brasileña de fútbol / Perfil antropométrico de jogadores sub-15 a profissionais da seleção brasileira de futebol

ABSTRACT Introduction: Although competitiveness rises progressively increases according to age groups, players must stand out in their playing position at all ages to win a spot on their National Teams. The differences among match physical and technical demands could also influence which anthropometrical aspects would be most importantly considered for National Team selection. Objectives: This study aimed describe and compare the anthropometric profile of soccer players from U15 to professional categories of the Brazilian National Soccer Team. Methods: The sample consisted of 673 players from the categories U15, U17, U20, U23 and PRO. Measurements of height, body mass, and sum of seven skinfolds from the Brazilian Football Confederation database between 2013 and 2021 were used to describe the players' anthropometric profile. Players were grouped according to categories, playing position, and those who were selected or not selected. Results: As expected, the results indicate that body mass increases with age and stabilizes from category U23 onwards. Body mass and the sum of seven skinfolds increase within the U15 category (U15.1 vs. U15.2), while height and body mass increase within the U17 category (U17.1 vs. U17.2). Defenders and fullbacks stabilize body mass and stature prior to U17, while midfielders, strikers, and goalkeepers stabilize body mass later, with midfielders and strikers at U20, and goalkeepers at U23. Goalkeepers and defenders were the players with the greatest height and body mass compared to the other positions in all categories. The selected and non-selected players in the different categories had similar anthropometric profiles. Conclusion: From the results, there is a diversity in anthropometric profile within the positions and a difference in maturation according to the players' positions. This study can be used by coaches, physical trainers and sport scientists as normative data about the anthropometric profile of Brazilian men's soccer teams, establishing a benchmark. Level of Evidence III; Retrospective and Comparative Study.

RESUMEN Introducción: Aunque la competitividad aumenta progresivamente según los grupos de edad, los jugadores deben destacar en su posición de juego a todas las edades para ganarse un puesto en sus selecciones nacionales. Las diferencias entre las exigencias físicas y técnicas de los partidos también pueden influir en qué aspectos antropométricos serían más importantes para la selección nacional. Objetivos: Este estudio tuvo como objetivo describir y comparar el perfil antropométrico de futbolistas masculinos de menores de 15 años a categorías mayores de las selecciones brasileñas de fútbol. Métodos: La muestra estuvo compuesta por 673 jugadores de las siguientes categorías: Sub 15 (U15), Sub 17 (U17), Sub 20 (U20), Sub 23 (U23) y Profesional (PRO). Se utilizaron medidas de estatura, masa corporal y la suma de 7 pliegues cutáneos de la base de datos de la Confederación Nacional de Fútbol de Brasil entre 2013 y 2021 para describir el perfil antropométrico de los jugadores. Los jugadores se agruparon según los tramos de edad oficiales, la posición de juego y los seleccionados y no seleccionados. Resultados: Como era de esperar, los resultados indican que la masa corporal aumenta con la edad y se estanca a partir de la categoría U23. La masa corporal y la suma de 7 pliegues cutáneos aumentan dentro de la categoría U15 (U15.1 vs. U15.2), mientras que la estatura y la masa corporal aumentan dentro de la U17 (U17.1 vs. U17.2). Los defensas centrales y los laterales estabilizan antes la masa corporal y la estatura a partir de la U17, mientras que los mediocampistas, delanteros y porteros estabilizan la masa corporal más tarde, con los mediocampistas y delanteros en la U20 y los porteros en la U23. Los porteros y defensas centrales fueron los grupos que mostraron mayor estatura y masa corporal respecto a otras posiciones en todos los tramos de edad. Los jugadores seleccionados y no seleccionados en diferentes tramos de edad tienen un perfil antropométrico similar. Conclusión: Con base en los resultados, existe diversidad en el perfil antropométrico dentro de las posiciones de juego y diferencia en la maduración según la posición de los jugadores. Este estudio puede ser utilizado por entrenadores, preparadores físicos y científicos del deporte como dato normativo sobre el perfil antropométrico de las selecciones masculinas de fútbol de Brasil, estableciendo un punto de referencia. Nivel de Evidencia III; Estudio Retrospectivo Comparativo.

RESUMO Introdução: Embora a competitividade aumente progressivamente de acordo com as faixas etárias os jogadores devem se destacar em sua posição de jogo em todas as idades para conquistar uma vaga em suas equipes nacionais. As diferenças entre as exigências físicas e técnicas dos jogos também podem influenciar quais aspectos antropométricos seriam mais importantes para a seleção da equipe nacional. Objetivo: Este estudo teve por objetivo descrever e comparar o perfil antropométrico de jogadores de futebol da categoria sub 15 ao profissional da Seleção Brasileira de Futebol. Métodos: A amostra consistiu de 673 jogadores das seguintes categorias: sub 15 (U15) sub 17 (U17) sub 20 (U20) sub 23 (U23) e profissional (PRO). Medidas da estatura massa corporal e soma das sete dobras cutâneas do banco de dados da Confederação Brasileira de Futebol entre 2013 e 2021 foram utilizadas para descrever o perfil antropométrico dos jogadores. Os jogadores foram agrupados de acordo com as categorias posição de jogo e aqueles que foram selecionados ou não selecionados. Resultados: Como esperado os resultados indicam que a massa corporal aumenta com a idade e estabiliza a partir da categoria U23. A massa corporal e a soma das sete dobras cutâneas aumentam dentro da categoria U15 (U15.1 vs. U15.2) enquanto a estatura e a massa corporal aumentam dentro da categoria U17 (U17.1 vs. U17.2). Os zagueiros e laterais estabilizam a massa corporal e a estatura antes do U17 enquanto os meio campistas atacantes e goleiros estabilizam a massa corporal posteriormente com os meio campistas e atacantes no U20 e goleiros no U23. Os goleiros e os zagueiros foram os jogadores que apresentaram maior estatura e massa corporal comparados às outras posições em todas as categorias. Os jogadores selecionados e não-selecionados nas diferentes categorias apresentam perfil antropométrico semelhante. Conclusão: Baseando-se nos resultados há uma diversidade no perfil antropométrico dentro das posições e uma diferença na maturação de acordo com as posições dos jogadores. Este estudo pode ser utilizado por treinadores preparadores físicos e cientistas do esporte como dados normativos sobre o perfil antropométrico das seleções masculinas do futebol brasileiro estabelecendo um benchmark. Nível de Evidência III; Estudo Retrospectivo Comparativo.

Is physical performance affected by non-steroidal anti-inflammatory drugs use? A systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis aim to analyze the effects of ingesting non-steroidal anti-inflammatory drugs (NSAIDs) on physical performance, muscle strength, and muscle damage in three different moments: immediately, 24 and 48 h after resistance exercise practice. METHODS: Relevant studies were researched in three databases (PubMed, Web of Science and SPORTDiscus) in April 2023. After excluding duplicates, the decision to include or exclude studies was made by two independent investigators in the following steps: (I) the study title; (II) the study abstract; and (III) the complete study manuscript. The following characteristics were recorded: (I) first author, (II) year of publication, (III) sample size, (IV) method of NSAIDs administration, (V) exercise protocol, and (VI) analyzed variable results. The studies selected were divided into trials that evaluated the effects of NSAIDs ingestion on performance indices of resistance exercise, endurance exercise and resistance training. RESULTS: The meta-analysis, based only on resistance exercises, revealed that both performance and muscle strength were similar between placebo or NSAID treatment immediately and 24 h after resistance exercise practice. An ergolytic effect was found 48 hours after resistance exercise (mean effect size (ES) = -0.42; 95% CI: -0.71, -0.12; p = 0.132), as well as reduced muscle strength (ES = -0.50; 95% CI: -0.83, -0.16; p = 0.072). Additionally, NSAID use did not prevent muscle waste as seen by the unchanged CK plasma concentration at all timetables. CONCLUSION: The data of the present meta-analysis indicate that NSAID use is ineffective in improving resistance performance and muscle strength, as well as exercise recovery. When considering the practical application of using NSAIDs to improve exercise capacity and strength gains, the present data supports that consumption of analgesic drugs as an endurance performance enhancer or as a muscle anabolic must not be recommended.

Skeletal muscle dysfunctions in pulmonary arterial hypertension: Effects of aerobic exercise training.

Pulmonary arterial hypertension is associated with skeletal muscle myopathy and atrophy and impaired exercise tolerance. Aerobic exercise training has been recommended as a non-pharmacological therapy for deleterious effects imposed by pulmonary arterial hypertension. Aerobic physical training induces skeletal muscle adaptations via reduced inflammation, improved anabolic processes, decreased hypoxia and regulation of mitochondrial function. These benefits improve physical exertion tolerance and quality of life in patients with pulmonary arterial hypertension. However, the mechanisms underlying the therapeutic potential of aerobic exercise to skeletal muscle disfunctions in patients with pulmonary arterial hypertension are not well understood yet. This minireview highlights the pathways involved in skeletal muscle adaptations to aerobic exercise training in patients with pulmonary arterial hypertension.

Differences between 48 and 72-hour intervals on match load and subsequent recovery: a report from the Brazilian under-20 national football team.

Purpose: To compare the external and internal load and subsequent recovery of football players after international tournament matches separated by 48 h vs. 72 h. Methods: A total of 14 male football players from the Brazilian National Team, competing in the 2019 South American Under-20 Championship, participated in the study. Match load was quantified using GPS variables and perceived exertion ratings (1). Additionally, before and 13-15 h after each match, players answered questions about the number of hours and quality of sleep, recovery status, and muscle soreness (0-10) and provided a blood sample for creatine kinase and reactive C-protein analysis. Values of all variables were compared between matches played with 48-h intervals (matches 1-4) and 72-h intervals (matches 5-8). Results: No significant differences in performance or perceptual parameters were observed between matches (p = 0.136-0.953). However, CK was higher in matches 1-4 compared to matches 5 and 6; and ΔPCR was higher in matches 2 and 3 compared to matches 5 and 6, and in match 4 compared to matches 5 and 8. Conclusions: After matches with a 48-h rest interval, players showed increased markers of inflammation and muscle damage compared to matches with a 72-h rest interval.

Acute and chronic effects of physical exercise on IgA and IgG levels and susceptibility to upper respiratory tract infections: a systematic review and meta-analysis.

This systematic review and meta-analysis aimed at evaluating acute and chronic effects of physical exercise on IgA and IgG levels, as well as its relationship with the susceptibility to develop upper respiratory tract infections (URTI). This systematic review and meta-analysis was conducted and reported in accordance with PRISMA statement. A systematic search of PubMed, Web of Science, and EMBASE was performed in July 2020. This systematic review and meta-analysis included studies in which participants performed acute exercise or chronic physical training and were subjected to analyses of URTI incidence and concentrations of IgA and IgG. The selected studies for systematic review were divided into the following three groups: (I) trials that evaluated the effects of acute exercise in sedentary subjects, (II) trials that evaluated the effects of acute exercise in athletes/trained individuals, and (III) trials that evaluated the effects of chronic physical training on the incidence of URTI, as well as on the levels of IgA and IgG. Acute exercise increases the IgA levels in trained subjects but does not affect its levels in untrained subjects. Such increase in IgA levels induced by acute exercise is greater in trained individual that performed ultramarathon. On the other hand, chronic physical training reduces IgA levels in both trained and untrained subjects, does not change IgA levels in non-military subjects, besides from not affecting IgG levels. The present systematic review and meta-analysis indicates that acute exercise positively influences IgA levels in trained individuals, being this effect pronounced when a strenuous exercise such as ultramarathon is executed. Chronic physical training, in turn, does not affect IgG levels.

Fatigue and Recovery Time Course After Female Soccer Matches: A Systematic Review And Meta-analysis.

BACKGROUND: This study aimed to analyze the extent of fatigue responses after female soccer matches and the ensuing recovery time course of performance, physiological, and perceptual responses. METHODS: Three databases (PubMed, Web of Science, and SPORTDiscus) were searched in October 2020 and updated in November 2021. Studies were included when participants were female soccer players, regardless of their ability level. Further, the intervention was an official soccer match with performance, physiological, or perceptual parameters collected pre- and post-match (immediately, 12 h, 24 h, 48 h, or 72 h-post). RESULTS: A total of 26 studies (n = 465 players) were included for meta-analysis. Most performance parameters showed some immediate post-match reduction (effect size [ES] = - 0.72 to - 1.80), apart from countermovement jump (CMJ; ES = - 0.04). Reduced CMJ performance occurred at 12 h (ES = - 0.38) and 24 h (ES = - 0.42) and sprint at 48 h post-match (ES = - 0.75). Inflammatory and immunological parameters responded acutely with moderate-to-large increases (ES = 0.58-2.75) immediately post-match. Creatine kinase and lactate dehydrogenase alterations persisted at 72 h post-match (ES = 3.79 and 7.46, respectively). Small-to-moderate effects were observed for increased cortisol (ES = 0.75) and reduced testosterone/cortisol ratio (ES = -0.47) immediately post-match, while negligible to small effects existed for testosterone (ES = 0.14) and estradiol (ES = 0.34). Large effects were observed for perceptual variables, with increased fatigue (ES = 1.79) and reduced vigor (ES = - 0.97) at 12 h post-match, while muscle soreness was increased immediately post (ES = 1.63) and at 24 h post-match (ES = 1.00). CONCLUSIONS: Acute fatigue exists following female soccer matches, and the performance, physiological, and perceptual parameters showed distinctive recovery timelines. Importantly, physical performance was recovered at 72 h post-match, whereas muscle damage markers were still increased at this time point. These timelines should be considered when planning training and match schedules. However, some caution should be advised given the small number of studies available on this population. REGISTRATION: The protocol for this systematic review was pre-registered on the International Prospective Register of Systematic Reviews (PROSPERO, Registration Number: CRD42021237857).

Exercise-based cardiac rehabilitation after myocardial revascularization: a systematic review and meta-analysis.

BACKGROUND: The present study aimed to analyze the effects of exercise-based cardiac rehabilitation (CR) on physical performance after myocardial revascularization. In addition, we compared the type and duration of exercise-based CR protocols to determine which ones produced the best performance improvements. METHODS: This systematic review and meta-analysis was conducted and reported in accordance with PRISMA statement. A systematic search of PubMed, Web of Science, SPORTDiscus and ProQuest, was performed in July 2020. Studies that met the following criteria were included: (i) participants submitted to myocardial revascularization (i.e., coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI)), (ii) participants submitted to exercise-based CR, and (iii) participants submitted to protocols for assessing physical performance before and after the exercise-based CR. RESULTS: Thirteen and eleven studies evaluating the effects of exercise-based CR after myocardial revascularization were included in the systematic review and meta-analysis, respectively. Exercise-based CR increased physical performance after myocardial revascularization (mean effect size (ES) 0.75; 95% confidence interval (CI) 0.62, 0.88), particularly when aerobic (ES 0.85; 95% CI 0.68, 1.01) and combined training (ES 1.04; 95% CI 0.70, 1.38) lasting 8-12 weeks (ES 1.20; 95% CI 0.87, 1.53) was prescribed. CONCLUSIONS: The present systematic review and meta-analysis indicates that exercise-based CR increases physical performance after myocardial revascularization. The prescription of physical training for these patients should emphasize aerobic and combined training lasting at least 8-12 weeks, which is more effective in improving physical performance. IMPACT: Our findings demonstrate the effectiveness of physical training in improving physical performance after myocardial revascularization.

Effects of Increased Central Cholinergic Activity on the Metabolic Challenge Induced by Submaximal Exercise in Rats: Adrenomedullary Secretion Influences.

AIM: The aim of this study was to assess the influence of adrenomedullary secretion on the plasma glucose, lactate, and free fatty acids (FFAs) during running exercise in rats submitted to intracerebroventricular (i.c.v.) injection of physostigmine (PHY). PHY i.c.v. was used to activate the central cholinergic system. METHODS: Wistar rats were divided into sham-saline (sham-SAL), sham-PHY, adrenal medullectomy-SAL, and ADM-PHY groups. The plasma concentrations of glucose, lactate, and FFAs were determined immediately before and after i.c.v. injection of 20 µL of SAL or PHY at rest and during running exercise on a treadmill. RESULTS: The i.c.v. injection of PHY at rest increased plasma glucose in the sham group, but not in the ADM group. An increase in plasma glucose, lactate, and FFAs mobilization from adipose tissue was observed during physical exercise in the sham-SAL group; however, the increase in plasma glucose was greater with i.c.v. PHY. Moreover, the hyperglycemia induced by exercise and PHY in the ADM group were blunted by ADM, whereas FFA mobilization was unaffected. CONCLUSION: These results indicate that there is a dual metabolic control by which activation of the central cholinergic pathway increases plasma glucose but not FFA during rest and exercise, and that this hyperglycemic response is dependent on adrenomedullary secretion.

Inhibition of nNOS in the paraventricular nucleus of hypothalamus decreases exercise-induced hyperthermia.

The paraventricular nucleus of the hypothalamus (PVN) is an important site for autonomic control, which integrates thermoregulation centers and sympathetic outflow to thermoeffector organs. PVN neurons express the neuronal isoform of nitric oxide synthase (nNOS) whose expression is locally upregulated by physical exercise. Thus, the aim of the present study was to evaluate the role of nNOS in the PVN in the exercise-induced hyperthermia. Seven days after surgery, male Wistar rats received bilateral intra-PVN microinjections of the selective nNOS inhibitor Nw-Propyl-L-Arginine (NPLA) or vehicle (saline) and were submitted to an acute progressive exercise session on a treadmill until fatigue. Abdominal and tail skin temperature (Tabd and Ttail, respectively) were measured, and the threshold (Hthr; °C) and sensitivity (Hsen) for heat dissipation calculated. Performance variables were also collected. During the progressive exercise protocol, all animals displayed an increase in the Tabd. However, compared to vehicle group, the microinjection of NPLA in the PVN attenuated the exercise-induced hyperthermia. There was no difference in Ttail or Hthr between NPLA and control rats. In contrast, Hsen was increased in the NPLA group compared to vehicle. In addition, heat storage was lower in NPLA-treated animals. Despite the temperature differences, inhibition of nNOS in the PVN did not affect running performance on the treadmill. These results suggest that nitrergic signaling within the PVN, under nNOS activation, drives the increase of body temperature, being necessary for the proper thermal regulatory mechanisms during progressive exercise-induced hyperthermia.

Impaired thermoregulation in spontaneously hypertensive rats during physical exercise is related to reduced hypothalamic neuronal activation.

This study aimed to evaluate the physical exercise-induced neuronal activation in brain nuclei controlling thermoregulatory responses in hypertensive and normotensive rats. Sixteen-week-old male normotensive Wistar rats (NWRs) and spontaneously hypertensive rats (SHRs) were implanted with an abdominal temperature sensor. After recovery, the animals were subjected to a constant-speed treadmill running (at 60% of the maximum aerobic speed) for 30 min at 25 °C. Core (Tcore) and tail-skin (Tskin) temperatures were measured every minute during exercise. Ninety minutes after the exercise, the rats were euthanized, and their brains were collected to determine the c-Fos protein expression in the following areas that modulate thermoregulatory responses: medial preoptic area (mPOA), paraventricular hypothalamic nucleus (PVN), and supraoptic nucleus (SON). During treadmill running, the SHR group exhibited a greater increase in Tcore and an augmented threshold for cutaneous heat loss relative to the NWR group. In addition, the SHRs showed reduced neuronal activation in the mPOA (< 49.7%) and PVN (< 44.2%), but not in the SON. The lower exercise-induced activation in the mPOA and PVN in hypertensive rats was strongly related to the delayed onset of cutaneous heat loss. We conclude that the enhanced exercise-induced hyperthermia in hypertensive rats can be partially explained by a delayed cutaneous heat loss, which is, in turn, associated with reduced activation of brain areas modulating thermoregulatory responses.

Involvement of brainstem noradrenergic system in cutaneous heat loss during exercise.

The involvement of brainstem noradrenergic system in thermoregulation during exercise was evaluated by assessing the neuronal activation of A1, A2, locus coeruleus (LC) during exercise. Male Wistar rats weighing 280-330 g were used in the present study. Ninety minutes after exercise bout until fatigue, animals were anaesthesiated and brain removed and processed immunohistochemically for Fos protein and tyrosine hydroxylase in A1, A2 and LC and for Fos in POA subregions. Core and tail temperature were recorded during all running period by telemetry system. Heat storage rate (HSR, cal.min-1), maximum tail vasoconstriction (°C) and vasodilatation threshold (°C) were calculated and correlated with Fos expression in all nuclei studied. Fos expression in LC correlated inversely with maximum tail skin vasoconstriction (r = -0.787, p < 0.03) and HSR (r = -0.834, p < 0.02) and positively to time to fatigue (r = 0.862, p < 0.01). A1 nucleus showed an inverse correlation with tail skin vasodilatation threshold (r = -0.861, p < 0.01). Fos expression in LC correlated inversely with Fos expression in the median (MnPO, r = -0.909, p < 0.01) and medial preoptic nucleus (MPOM, r = -0.942, p < 0.05). Our results bring further evidences that noradrenergic neurons from LC and A1 nuclei are involved in cutaneous heat loss mechanisms during exercise. LC nucleus probably modulates the sympathetic tonus of tail artery and integrates the central network LC / POA that could represent an important circuitry of temperature regulation during exercise. Also, noradrenergic neurons from A1 nucleus could be involved in cutaneous heat loss during exercise by modulating of vasodilatation threshold.

Procura pelo treinamento personalizado e fidelização: um estudo com clientes de personal trainer nas academias de Divinópolis-MG / Pursuit for customized training and loyalty: a study with clients of personal trainer in the gyms of Divinópolis-MG

A procura por uma vida saudável tem aumentado no Brasil, consequentemente, o número de adeptos a prática de exercícios físicos cresce significativamente, o que fomenta a profissão de personal trainer, um serviço oferecido na área da educação física. O estudo teve como objetivo identificar quais dimensões motivacionais estimulam esses clientes a buscar por este serviço de personal trainer e o que os levam à fidelização. A ferramenta de análise do estudo foi o inventário IMPRAFE- 54, com perguntas relacionadas à motivação da prática regular de exercício físico, adaptando para a prática regular de exercício físico orientado pelo personal trainer. A amostra foi composta por 30 indivíduos de ambos os sexos, com 33 anos ±15,02, praticantes de exercício físico regularmente, por pelo ao menos duas vezes por semana e com orientação de um personal trainer, por um período superior a seis meses nas academias da cidade de Divinópolis-MG. Os resultados foram analisados através do software estatístico SPSS 20.0 for Windows Release. O tempo de prática de exercício físico anterior à realização do acompanhamento dos treinamentos personalizado foi de 6,3 ± 5,8 anos entre os entrevistados, já o tempo médio de prática orientado por um personal trainer foi de 2,7 ± 2,3 anos e com uma frequência semanal de treinamentos de 3,7 ± 1,1. Os resultados mostraram que Saúde é um fator determinante tanto para prática de exercício físico, quanto para buscar o treinamento com o personal trainer, fatores como prazer e beleza também se mostram relevantes para realizar exercício físico orientado, no entanto, o que mais demonstrou motivar a fidelização dos clientes foi a atenção dada pelo personal trainer...(AU)

The demand for a healthy life has been increased in Brazil; therefore, the number of people who practice physical activity has also increased significantly at the gym, because of this increase the profession of personal trainer became a new service offered in the area of physical education. The aim of this study is discovery which motivational dimension makes clients to pursuit a custom training and what makes this people to loyalty this kind of service. The research was developed using the method IMPRAFE - 54 with questions related to the motivation of regular physical exercises practices, adjusted for the regular physical exercise's practices orientated by a personal trainer. The sample was composed of thirty people of both genders between eighteen and ninety-one years old, who practice exercises for six months or more at least twice a week followed by a professional in the city of Divinópolis - MG. The results analyze was done in the statistic software package SPSS 20.0 for Windows Release. The time of physical practice before the custom training was 6,3 ± 5,8 years among the interviewed, in addiction the medium time of training conducted by a personal trainer was 2,7 ± 2,3 years with weekly frequency of 3,7 ± 1,1 per week. The results have shown that health is the main factor for the practice of exercise, consequently for the choice of a Personal Trainer, factors as pleasure and beauty are also relevant motivation issues to practice orientated physical exercises. Then, the main point to retain clients is the attention given by the professional...(AU)

Thermoregulation in Hypertensive Rats during Exercise: Effects of Physical Training / Termorregulação durante o Exercício em Ratos Hipertensos: Efeitos do Treinamento Físico

Abstract Background: Spontaneously hypertensive rats (SHR) show deficit in thermal balance during physical exercise. Objective: To assess the effects of low-intensity physical exercise training on thermal balance of hypertensive rats undergoing an acute exercise protocol. Methods: Sixteen-week-old male Wistar rats and SHR were allocated into four groups: control Wistar rats (C-WIS), trained Wistar (T-WIS), control SHR (C-SHR) and trained SHR (T-SHR). Treadmill exercise training was performed for 12 weeks. Blood pressure, resting heart rate and total exercise time was measured before and after the physical exercise program. After the exercise program, a temperature sensor was implanted in the abdominal cavity, and the animals subjected to an acute exercise protocol, during which internal body temperature, tail skin temperature and oxygen consumption until fatigue were continuously recorded. Mechanical efficiency (ME), work, heat dissipation threshold and sensitivity were calculated. Statistical significance was set at 5%. Results: Physical training and hypertension had no effect on thermal balance during physical exercise. Compared with C-WIS, the T-WIS group showed higher heat production, which was counterbalanced by higher heat dissipation. Hypertensive rats showed lower ME than normotensive rats, which was not reversed by the physical training. Conclusion: Low-intensity physical training did not affect thermal balance in SHR subjected to acute exercise.

Resumo Fundamento: Ratos espontaneamente hipertensos (SHR) apresentam déficits no balanço térmico durante o exercício físico. Objetivo: Avaliar os efeitos do treinamento físico de baixa intensidade sobre o balanço térmico de ratos hipertensos submetidos a um protocolo de exercício físico agudo. Métodos: Ratos machos Wistar e SHR, com 16 semanas de idade, foram divididos em quatro grupos experimentais: Wistar controle (WIS-C), Wistar treinado (WIS-T), SHR controle (SHR-C) e SHR treinado (SHR-T). O treinamento físico em esteira rolante foi realizado durante 12 semanas. A pressão arterial, a frequência cardíaca de repouso e o tempo de exercício foram medidos previamente e após o programa de treinamento físico. Após o programa de treinamento físico, um sensor de temperatura foi implantado na região intraperitoneal e os ratos foram submetidos a um protocolo de exercício físico agudo com registros contínuos da temperatura corporal interna, temperatura da pele da cauda e do consumo de oxigênio até a fadiga. A eficiência mecânica (EM), o trabalho, o limiar e a sensibilidade para dissipação de calor foram calculados. Para as análises estatísticas o nível de significância adotado foi de 5%. Resultados: O treinamento físico e a hipertensão arterial não alteraram o balanço térmico durante o exercício físico. O grupo WIS-T quando comparado ao WIS-C, apresentou maior produção de calor, que foi contrabalanceado por uma maior dissipação de calor. Os animais hipertensos apresentaram menor EM em comparação aos animais normotensos, e o treinamento físico não foi capaz de reverter esta alteração. Conclusão: O treinamento físico de baixa intensidade não provocou alterações no balanço térmico de ratos hipertensos submetidos a um protocolo de exercício físico agudo.

Thermoregulation in Hypertensive Rats during Exercise: Effects of Physical Training.

BACKGROUND: Spontaneously hypertensive rats (SHR) show deficit in thermal balance during physical exercise. OBJECTIVE: To assess the effects of low-intensity physical exercise training on thermal balance of hypertensive rats undergoing an acute exercise protocol. METHODS: Sixteen-week-old male Wistar rats and SHR were allocated into four groups: control Wistar rats (C-WIS), trained Wistar (T-WIS), control SHR (C-SHR) and trained SHR (T-SHR). Treadmill exercise training was performed for 12 weeks. Blood pressure, resting heart rate and total exercise time was measured before and after the physical exercise program. After the exercise program, a temperature sensor was implanted in the abdominal cavity, and the animals subjected to an acute exercise protocol, during which internal body temperature, tail skin temperature and oxygen consumption until fatigue were continuously recorded. Mechanical efficiency (ME), work, heat dissipation threshold and sensitivity were calculated. Statistical significance was set at 5%. RESULTS: Physical training and hypertension had no effect on thermal balance during physical exercise. Compared with C-WIS, the T-WIS group showed higher heat production, which was counterbalanced by higher heat dissipation. Hypertensive rats showed lower ME than normotensive rats, which was not reversed by the physical training. CONCLUSION: Low-intensity physical training did not affect thermal balance in SHR subjected to acute exercise.

Brain Temperature in Spontaneously Hypertensive Rats during Physical Exercise in Temperate and Warm Environments.

This study aimed to evaluate brain temperature (Tbrain) changes in spontaneously hypertensive rats (SHRs) subjected to two different physical exercise protocols in temperate or warm environments. We also investigated whether hypertension affects the kinetics of exercise-induced increases in Tbrain relative to the kinetics of abdominal temperature (Tabd) increases. Male 16-week-old normotensive Wistar rats (NWRs) and SHRs were implanted with an abdominal temperature sensor and a guide cannula in the frontal cortex to enable the insertion of a thermistor to measure Tbrain. Next, the animals were subjected to incremental-speed (initial speed of 10 m/min; speed was increased by 1 m/min every 3 min) or constant-speed (60% of the maximum speed) treadmill running until they were fatigued in a temperate (25°C) or warm (32°C) environment. Tbrain, Tabd and tail skin temperature were measured every min throughout the exercise trials. During incremental and constant exercise at 25°C and 32°C, the SHR group exhibited greater increases in Tbrain and Tabd relative to the NWR group. Irrespective of the environment, the heat loss threshold was attained at higher temperatures (either Tbrain or Tabd) in the SHRs. Moreover, the brain-abdominal temperature differential was lower at 32°C in the SHRs than in the NWRs during treadmill running. Overall, we conclude that SHRs exhibit enhanced brain hyperthermia during exercise and that hypertension influences the kinetics of the Tbrain relative to the Tabd increases, particularly during exercise in a warm environment.

ÓXIDO NÍTRICO E DINÂMICA DE CA2+ EM CARDIOMIÓCITOS: INFLUÊNCIA DA CAPACIDADE DE EXERCÍCIO / NITRIC OXIDE AND CA2+ DYNAMICS IN CARDIOMYOCYTES: INFLUENCE OF EXERCISE CAPACITY / ÓXIDO NÍTRICO Y DINAMICA DE CA2+ EN CARDIOMIOCITOS: INFLUENCIA DE LA CAPACIDAD DE EJERCÍCIO

RESUMO Introdução: A capacidade intrínseca para o exercício aeróbico está relacionada com o inotropismo cardíaco. Por outro lado, a participação do óxido nítrico (NO) como mensageiro intracelular sobre a dinâmica do Ca2+ ainda permanece desconhecida em ratos com diferentes capacidades intrínsecas para o exercício. Objetivo: Avaliar se o NO modula diferentemente o transiente intracelular de Ca2+ e liberações espontâneas de Ca2+(sparks) em cardiomiócitos de ratos com diferentes capacidades intrínsecas para o exercício. Métodos: Ratos machos Wistar foram selecionados como desempenho padrão (DP) e alto desempenho (AD), de acordo com a capacidade de exercício até a fadiga, mensurada através de teste de esforço progressivo em esteira. Os cardiomiócitos dos ratos foram utilizados para determinar o transiente intracelular de Ca2+ e Ca2+sparks em microscópio confocal. Para estimar a contribuição do NO foi utilizado o inibidor das sínteses do NO (L-NAME, 100 µM). Os dados foram analisados através de ANOVA two-way seguido do pós-teste de Tukey e apresentados como médias ± EPM. Resultados: Os cardiomiócitos de ratos AD exibiram aumentos na amplitude do transiente de Ca2+ em comparação aos DP. Entretanto, o L-NAME aumentou a amplitude do transiente de Ca2+ somente em ratos DP. Não foram encontradas diferenças na constante de tempo de decaimento do transiente de Ca2+ (t) em cardiomiócitos de ratos com DP e AP, contudo, a administração do L-NAME diminuiu o t em cardiomiócitos em ambos os grupos. cardiomiócitos de ratos AD apresentaram menor amplitude e frequência de Ca2+sparks em comparação ao grupo DP. A administração de L-NAME aumentou a amplitude de Ca2+sparks em cardiomiócitos do grupo AD. Conclusão: O NO modula o transiente de Ca2+ e as sparks de Ca2+ em cardiomiócitos de ratos com diferentes capacidades intrínsecas para o exercício.

ABSTRACT Introduction: The intrinsic capacity to aerobic exercise is associated with cardiac inotropism. On the other hand, the contribution of nitric oxide (NO) as an intracellular messenger on Ca2+ dynamics remains unknown in rats with different intrinsic capacities to exercise. Objective: To evaluate whether NO modulates differently Ca2+ intracellular transient and spontaneous Ca2+ releases (sparks) in cardiomyocytes of rats with different intrinsic capacities to exercise. Methods: Male Wistar rats were selected as standard-performance (SP) and high-performance (HP), according to the exercise capacity until fatigue, assessed through a treadmill progressive stress test. Cardiomyocytes of rats were used to determine Ca2+ intracellular transient and Ca2+ sparks evaluated using confocal microscope. To estimate NO contribution, a NO synthase inhibitor (L-NAME, 100 µM) was used. Data were analyzed through two-way ANOVA followed by Tukey's post hoc test and expressed as means ± SEM. Results: Cardiomyocytes of HP rats exhibited higher Ca2+ transient amplitude compared to SP. However, L-NAME increased Ca2+ transient amplitude only in SP rats. No differences were found in Ca2+ transient decay time constant ( t) in cardiomyocytes of SP and HP rats. However, administration of L-NAME caused reduction of tin cardiomyocytes of both groups. Lower amplitude and frequency of Ca2+ sparks were found in cardiomyocytes of HS rats compared to SP group. Administration of L-NAME increased the amplitude of Ca2+ sparks in cardiomyocytes of the HP group. Conclusion: NO modulates Ca2+ transient and Ca2+ sparks in cardiomyocytes of rats with different intrinsic exercise capacities.

RESUMEN Introducción: La capacidad intrínseca para el ejercicio aeróbico está relacionada con el inotropismo cardiaco. Por otro lado, todavía se desconoce la contribución del óxido nítrico (ON) como mensajero intracelular sobre la dinámica del Ca2+ en ratones con diferentes capacidades intrínsecas para el ejercicio. Objetivo: Evaluar si el ON modula diferencialmente la variación transitoria intracelular de Ca2+ y las liberaciones espontaneas de Ca2+ (sparks) en cardiomiocitos de ratones con diferentes capacidades intrínsecas para el ejercicio. Métodos: Ratones machos Wistar fueron seleccionados como desempeño estándar (DE) y alto desempeño (AD), de acuerdo con la capacidad de ejercicio hasta la fatiga, medida a través del test de fuerza progresiva en la caminadora o cinta eléctrica. Los cardiomiocitos de los ratones fueron utilizados para determinar el tránsito intracelular y sparks de Ca2+ evaluados en microscopio confocal. Para estimar la contribución del ON fue utilizado un inhibidor de síntesis del ON (L-NAME, 100 µM). Los datos fueron analizados a través de un ANOVA two-way seguido de un post-test Tukey y presentados como promedios ± EPM. Resultados: Los cardiomiocitos de ratones AD mostraron aumento en la amplitud de la variación transitoria de Ca2+ en comparación con los DE. Así mismo, el L-NAME incremento la amplitud transitoria de Ca2+ solamente en ratones DE. No se encontraron diferencias en la constante del tiempo de decaimiento de la variación transitoria ( t ) de Ca2+ en cardiomiocitos de ratones DE e AD. Todavía, la administración de L-NAME mostro una reducción en el t en cardiomiocitos de ambos los grupos. Cardiomiocitos de ratones AD presentaron menor amplitud y frecuencia de sparks de Ca2+ en comparación al grupo DE. La administración de L-NAME incrementó la amplitud de sparks de Ca2+ en cardiomiocitos del grupo AD. Conclusión: El ON modula la variación de Ca2+ y sparks de Ca2+ en cardiomiocitos de ratones con diferentes capacidades intrínsecas para el ejercicio.

Resistance training regulates cardiac function through modulation of miRNA-214.

AIMS: To determine the effects of resistance training (RT) on the expression of microRNA (miRNA)-214 and its target in sarcoplasmic reticulum Ca2+-ATPase (SERCA2a), and on the morphological and mechanical properties of isolated left ventricular myocytes. MAIN METHODS: Male Wistar rats were divided into two groups (n = 7/group): Control (CO) or trained (TR). The exercise-training protocol consisted of: 4 × 12 bouts, 5×/week during 8 weeks, with 80% of one repetition maximum. KEY FINDINGS: RT increased the left ventricular myocyte width by 15% and volume by 12%, compared with control animals (p < 0.05). The time to half relaxation and time to peak were 8.4% and 4.4% lower, respectively, in cells from TR group as compared to CO group (p < 0.05). RT decreased miRNA-214 level by 18.5% while its target SERCA2a expression were 18.5% higher (p < 0.05). SIGNIFICANCE: Our findings showed that RT increases single left ventricular myocyte dimensions and also leads to faster cell contraction and relaxation. These mechanical adaptations may be related to the augmented expression of SERCA2a which, in turn, may be associated with the epigenetic modification of decreased miRNA-214 expression.

Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology.

Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.

Treinamento em corrida de baixa intensidade: propriedades estruturais e mecânicas da epífise proximal do fêmur de ratas osteopênicas / Low-intensity running training: structural and mechanical properties of the proximal femoral epiphysis in osteopenic female rats / Entrenamiento en carrera de baja intensidade: propriedades estructurales y mecánicas de la epífisis proximal femoral de ratas osteopénicas

Este estudo investigou os efeitos do treinamento em corrida de baixa intensidade (TCBI) sobre propriedades estruturais e mecânicas da epífise proximal do fêmur de ratas osteopênicas. Ratas Wistar [idade = 20 semanas; massa corporal = 271,42 ± 17,6 g] foram submetidas à ovariectomia (OVX) ou laparotomia (SHAM) e alocadas em quatro grupos: corrida OVX (CO, n = 12), controle OVX (CONO, n = 12), corrida SHAM (CS, n = 12) e controle SHAM (CONS, n = 12). Quinze dias pós-cirurgia, os grupos CO e CS foram submetidos ao TCBI em esteira (16 m/min, 60 min/dia, cinco dias/semana) por 10 semanas. O TCBI não alterou os efeitos deletérios da osteopenia induzida por ovariectomia sobre a densidade mineral do fêmur, a quantidade de osso trabecular no trocanter e colo do fêmur, a tenacidade e a força máxima de fratura do colo do fêmur de ratas.

This study investigated the effects of low-intensity running training (LIRT) on the structural and mechanical properties of the proximal femoral epiphysis in osteopenic female rats. Female Wistar rats [age = 20 weeks, body mass = 271.42 ± 17.6 g] were subjected to ovariectomy (OVX) or laparotomy (SHAM) and divided into four groups: running OVX (RO, n = 12), control OVX (CO, n = 12), running SHAM (RS, n = 12) and control SHAM (CS, n = 12). Two weeks after surgery RO and RS groups were submitted to a progressive LITR on a treadmill (60 min / day, 5 days / week) for 10 weeks. The LIRT did not alter the deleterious effects induced by ovariectomy on the femoral bone mineral density, the quantity of trabecular bone in the femoral great trocanter and neck, and femoral neck tenacity and resistance to fracture in female rats.

Este estudio investigó los efectos del entrenamiento en carera de baja intensidad (ECBI) en las propiedades estructurales y mecánicas de la epífisis proximal femoral de ratas osteopénicas. Ratas Wistar con edad de 20 semanas (peso corporal: 271.42 ± 17,6 g) fueran sometidas a ooforectomía (OVX) o laparotomía (SHAM) y asignados en cuatro grupos: carera OVX (CO, n = 12), control OVX (CONO, n = 12), carera SHAM (CS, n = 12) y control SHAM (CONS, n = 12). Quince días después de la cirugía los grupos CO y CS fueran sometidos al ECBI (16 m/ min; 60 min/día, 5 dias/semana) durante 10 semanas. El ECBI no cambió los efectos deletéreos de la osteopenia inducida por ooforectomía sobre la densidad mineral del fémur, la cantidad de hueso trabecular en el trocánter y cuello del fémur, la tenacidad y la resistencia ósea a la fractura del cuello del fémur de ratas.