Anderson Luiz Bezerra da Silveira

Acute Endocrine Responses to Different Strength Exercise Order in Men

Abstract This study compared the effects of order of muscle groups’ exercised (larger to smaller muscles vs. smaller to larger muscles) on the acute levels of total testosterone, free testosterone and cortisol during resistance training (RT) sessions. Healthy male participants (n=8; age: 28.8 ± 6.4 years; body mass: 87.0 ± 10.6 kg; body height: 181.0 ± 0.7 cm; BMI: 26.5 ± 4.1) were randomly separated into two experimental groups. The first group (LG-SM) performed an RT session (3 sets of 10 repetitions and a 2 min rest period) of the exercises in following order: bench press (BP), lat pulldown (LP), barbell shoulder press (BSP), triceps pushdown (TP) and barbell cut (BC). The second group (SM-LG) performed an RT session in following order: BC, TP, BSP, LA, BP. Blood was collected at the end of the last repetition of each session. Control samples of blood were taken after 30 min of rest. Significant differences were observed in the concentrations of total testosterone (p < 0.05), free testosterone (p < 0.0001) and cortisol (p < 0.0001) after both RT sessions in comparison to rest. However, when comparing LG-SM and SM-LG, no significant differences were found. The results suggest that, while RT sessions induce an acute change in the levels of testosterone and cortisol, this response is independent of the order of exercising muscle groups.

Cardiac ischemia/reperfusion injury is inversely affected by thyroid hormones excess or deficiency in male Wistar rats

Aim Thyroid dysfunctions can increase the risk of myocardial ischemia and infarction. However, the repercussions on cardiac ischemia/reperfusion (IR) injury remain unclear so far. We report here the effects of hypothyroidism and thyrotoxicosis in the susceptibility to IR injury in isolated rat hearts compared to euthyroid condition and the potential role of antioxidant enzymes. Methods Hypothyroidism and thyrotoxicosis were induced by administration of methimazole (MMZ, 300 mg/L) and thyroxine (T4, 12 mg/L), respectively in drinking water for 35 days. Isolated hearts were submitted to IR and evaluated for mechanical dysfunctions and infarct size. Superoxide dismutase types 1 and 2 (SOD1 and SOD2), glutathione peroxidase types 1 and 3 (GPX 1 and GPX3) and catalase mRNA levels were assessed by quantitative RT-PCR to investigate the potential role of antioxidant enzymes. Results Thyrotoxicosis elicited cardiac hypertrophy and increased baseline mechanical performance, including increased left ventricle (LV) systolic pressure, LV developed pressure and derivatives of pressure (dP/dt), whereas in hypothyroid hearts exhibited decreased dP/dt. Post-ischemic recovery of LV end-diastolic pressure (LVEDP), LVDP and dP/dt was impaired in thyrotoxic rat hearts, whereas hypothyroid hearts exhibited improved LVEDP and decreased infarct size. Catalase expression was decreased by thyrotoxicosis. Conclusion Thyrotoxicosis was correlated, at least in part, to cardiac remodeling and increased susceptibility to IR injury possibly due to down-regulation of antioxidant enzymes, whereas hypothyroid hearts were less vulnerable to IR injury.

EFEITO AGUDO DO ALONGAMENTO ESTÁTICO SOBRE A DESTREZA MANUAL DE JOVENS DESTREINADOS

OBJETIVO: Este estudo objetivou avaliar a influencia do alongamento sobre a funcao manual. METODOS: A amostra foi composta por 10 homens destreinados em um delineamento experimental cross-over randomizado, com quatro sessoes de testes. Cada sessao foi constituida apenas por um dos protocolos: a) controle ou b) serie unica de alongamento estatico passivo seguidos pelo minnesota Hand Dexterity Test ou pelo Teste de Preensao Manual com analise eletromiografica do Tempo de Reacao Manual. Para as comparacoes dos dados, o teste T de Student foi usado, com o indice de significância adotado de p ≤ 0,05. RESULTADOS: O alongamento aumentou a destreza manual em ambos Placing e Turning Tests, sem alterar a forca de preensao manual ou o tempo de reacao. CONCLUSAO: Os resultados indicam que o alongamento melhorou a destreza manual de jovens destreinados.