The swimming track start is a complex motor skill that utilizes asymmetric lower limb action. The purpose of this study was to explore whether it could be optimized by applying the commonly accepted view that there are asymmetries in the function and behaviors of the lower limbs. Initially, the study aimed to examine the relationship between various measures of lower limb asymmetry and the swimmers' preferences for forward foot placement in the swimming track start. Participants underwent a 7 week training period whereby both the left foot forward (LFF) and the right foot forward (RFF) track starts were practiced. The philosophy behind this training protocol was to ensure that participants received equal practice with the preferred and non-preferred stance so that a dominant stance, if it existed, could emerge. Consequently, the relationships between the dominant track start stance and the lower limb asymmetry measures could be determined more accurately. Participants were male (N=11) and female (N=11) swimmers, aged 12-16 years, from the UWA-Uniswim National Age Squad. Kinetic and kinematic data were collected for the track start prior to and following the 7 week training intervention. The intervention was finished when a participant had completed approximately 14 dive sessions where both the LFF and RFF track starts were practiced. The performance criterion measure was time to 5 m. Despite significant differences in vertical force and velocity contributions following the intervention, time to 5 m did not improve for either the LFF or the RFF track start. Four different measures of lower limb asymmetry were collected, including footedness, the preferred track start stance, and the dominant take-off limb for the unilateral and bilateral counter-movement jump (CMJ). Sixteen of 22 participants displayed changes in their dominant track start stance. Eleven participants showed biases for one stance (6 for the LFF & 5 for the RFF), and 11 participants remained or became more symmetrical. Results indicated that the preferred track start stance was the only measure of asymmetry that was significantly related to track start performance (x2[2]= 6.71, p=.04 for pre-intervention & x2[2]=7.77, p=.02 for post-intervention). All other measures of lower limb asymmetry were shown to be unrelated to track start preference and performance. It was suggested that the 7 week training intervention did not provide a sufficient amount of time to see conclusive effects on 5 m time or to make conclusive comparisons between the dominant track start stance and measures of asymmetry. Since the preferred track start corresponded with better performance less than 50% of the time, it was suggested that swimmers and coaches experiment with different dive techniques to find the start which is most effective for them and spend more time on them during training.

The purpose of this study was to separate acute and chronic effects of moderate exercise on the immune system by analyzing three sets of experimental and control groups; (1) 72 hours, (2) 1 week, (3) 2 weeks post exercise. Mice swam 5 days per week for 3 weeks accumulating a total of 125, 225, and 225 minutes of exercise in weeks 1, 2, and 3, respectively. Moderate swimming exercise did not result in a significant increase in SDH levels (p > 0.05). There was no change in tissue cell responses as measured by mitogen responsiveness, nor in splenic and thymic cell counts in response to the training regimen at any time point (p ≥ 0.05). Total, CD4, CD8, and T cell counts in the lymph nodes were significantly suppressed at 72 hours and 2 weeks post exercise (p ≤ 0.05). It appears that chronic exercise resulted in an increased trafficking of lymphatic cells, which could be interpreted as a sign of heightened immune reactivity.

Orientador: Miguel Arcanjo Areas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T12:08:35Z (GMT). No. of bitstreams: 1 Santos_GustavoBarbosados_M.pdf: 1865766 bytes, checksum: 33bc98691c7f175ef683408a35219198 (MD5) Previous issue date: 2010 / Resumo: Esteróides androgênicos anabolizantes (EAA) são indicados clinicamente para promover aumento da síntese protéica após queimaduras, cirurgias, radioterapia, no tratamento contraceptivo, no hipogonadismo, na osteoporose, na sarcopenia relacionada à idade e à pacientes portadores de HIV. Por outro lado, o uso indiscriminado dos EAA, com intuito de aumentar o desenvolvimento muscular, o desempenho físico, a capacidade aeróbia, a tolerância ao treinamento de alta intensidade e até mesmo para fins estéticos, é crescente entre atletas e esportistas recreacionais. O uso abusivo de EAA está relacionado à toxicidade cardíaca e hepática em consequência do aumento do estresse oxidativo. Por outro lado, estudos apontam a melatonina como substância com significativa ação antioxidante, apresentando efeitos benéficos no tratamento de doenças cardíacas. Este trabalho teve por objetivo avaliar os efeitos da melatonina sobre biomarcadores do estresse oxidativo e parâmetros cardiovasculares e hepáticos em ratos adultos sedentários ou treinados com natação e tratados com estanozolol. Os ratos foram distribuídos nos seguintes grupos: sedentário (S), sedentário+estanozolol (SE), sedentário+estanozolol+melatonina (SEM), treinado (T), treinado+estanozolol (TE) e treinado+estanozolol+melatonina (TEM). Realizou-se avaliação eletrocardiográfica no início e ao final do período experimental (6 semanas), sendo, então, determinada a pressão arterial, atividade de enzimas antioxidantes e da fosfatase alcalina e histologia do coração e do fígado. Os resultados mostraram que o estanozolol provocou bradicardia, queda do peso relativo do fígado e aumento da atividade das enzimas superóxido dismutase cardíaca e hepática, catalase cardíaca e fostatase alcalina hepática. Quando associado ao treinamento, estanozolol aumentou a pressão arterial sistólica e diastólica, o peso relativo do coração, desviou o eixo elétrico cardíaco para esquerda e provocou alterações hepatotóxicas. A administração da melatonina nos ratos tratados com EST, por sua vez, impediu o aumento da pressão arterial sistólica e diastólica e da atividade das enzimas catalase cardíaca, fostatase alcalina hepática além de impedir o desvio do eixo elétrico cardíaco causado pela hipertrofia ventricular esquerda induzida pelo estanozolol. Além disso, melatonina reduziu as alterações nos hepatócitos induzidas pelo estanozolol. Concluímos que, em nossas condições experimentais, a melatonina atenuou os efeitos adversos ao sistema cardiovascular e ao fígado causados pelo uso de doses suprafisiológicas de estanozolol / Abstract: Anabolic androgenic steroids (AAS) are nominated for clinical use to promote protein synthesis after burns, surgery, radiotherapy, on contraceptive treatment, osteoporosis, hypogonadism, age-related sarcopenia and HIV patients. However, the indiscriminate use of ASS aiming to stimulate muscular development, physical performance, aerobic capacity, tolerance to high-intensity training and with aesthetic purpose is increasing among athletes and recreational sportsmen. The abusive use of ASS is related to oxidative stress-induced cardiac and hepatic toxicity. Nonetheless, many studies point to melatonin as a substance with antioxidant properties, with beneficial effects on cardiovascular diseases treatment. The purpose of this study was to assess melatonin's effects on oxidative stress biomarkers, cardiovascular and liver parameters in stanozolol-treated trained rats. Rats were divided into the following groups: sedentary (S), sedentary+stanozolol (SS), sedentary+stanozolol+melatonin (SSM), trained (T), trained+stanozolol (TS) and trained+stanozolol+melatonin (TSM). Electrocardiography assessment were performed at the beginning and at the end of experimental period, and then, blood pressure, antioxidant enzymes and phosphatase alkaline activities, heart and liver histology were determined. Stanozolol induced bradycardia, relative liver weight decreased and increased cardiac and liver superoxide dismutase, cardiac catalase and liver phosphatase alkaline activities. Stanazolol plus training induced increased systolic and diastolic blood pressure, relative heart weight, left cardiac axis deviation and toxic liver damage. Melatonin induced decreased systolic and diastolic blood pressure, cardiac catalase and liver phosphatase alkaline activities, and prevented stanazolol-induced left cardiac axis deviation. Furthermore, melatonin decreased stanozolol-induced liver damage. In conclusion, under our experimental conditions, the side effects of supraphysiology doses of stanozolol on liver and cardiovascular system are mitigated by melatonin / Mestrado / Fisiologia / Mestre em Biologia Funcional e Molecular

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Total and high-density lipoprotein cholesterol (TC and HDL-C) and TC/HDL-C ratio were compared in 30 adult male recreational swimmers and 21 sedentary controls. Percentage of body fat, number of cigarettes smoked daily, and daily alcohol consumption were assessed for both groups. Maximum workout heartrate, weekly swim duration and weekly swim distance of the swimmers were also measured. Maximum workout heartrate (mean ± S. D. ) was 140 ± 24 beats per minute . Mean weekly swim duration was 142 ± 84 minutes, and mean weekly swim distance was 5317 ± 3217 yards. Swimmers and controls were nonsignificantly different in age, number of cigarettes smoked daily, and percent body fat. In this sample, the swimmers consumed significantly higher levels of alcohol than the non-swimmers. TC and HDL-C concentrations of swimmers were not significantly different than controls, (204 vs 199 mg/dl, and 48 vs 47 mg/dl, respectively). TC/HDL-C ratio of swimmers was 4.69, while that of controls was 4.65. This study showed that adult male recreational swimmers who train at low intensity do not differ significantly in total and HDL-C or TC/HDL-C ratio from male sedentary controls. / M.S.