Influence of exercising condition and degree of improvement in sit-to-stand power index during a 12-week Chokin exercise program on exercise continuation after one year / 体力科学

<p>We aimed to elucidate the impact of the conducting state in exercise programs and the degree of improvement in sit-to-stand power index (STS-PI) on the continuation of Chokin exercise by participants one year from the completion of the intervention period. Subjects participated in a 12-week Chokin exercise class for the elderly, which consisted of 10 body mass-based exercises. As variables indicating exercise conditions, the number of exercise days weekly and the total number of sets performed during the intervention period were adopted. STS-PI was calculated using the time required to perform 10-times-repeated sit-to-stand task, and its relative change (%∆STS-PI) was used to represent the degree of improvement in physical function. Among 52 men and 129 women who responded to the inquiry about the continuation of Chokin exercise one year from the completion of the intervention period, 32 men and 93 women confirmed continuation of the exercise program. Logistic regression analysis showed that %∆STS-PI for men, as well as %∆STS-PI and the number of exercise days weekly for women, were factors associated with the decision of subjects to continue the Chokin exercise. These results indicate that the degree of improvement in STS-PI associated with the Chokin exercise class is a factor for continuing the exercise program one year from the completion of the intervention period, at least in elderly men and women. Furthermore, high exercise frequency during the intervention period may be associated with the decision to continue Chokin exercise after the completion of the intervention among women.</p>

Efeito de diferentes frequências semanais de treinamento sobre parâmetros de estresse oxidativo / Effect of different frequencies weekly training on parameters of oxidative stress

Durante a contração muscular intensa induzida pelo exercício físico, há aumento na produção de espécies reativas de oxigênio, ocasionando estresse oxidativo em diversos órgãos, dentre eles o fígado e o coração. O treinamento físico pode aumentar as defesas antioxidantes e diminuir o estresse oxidativo. Contudo, ainda existem dúvidas sobre a frequência de treinamento necessária para melhorar parâmetros de estresse oxidativo. Este trabalho tem como objetivo verificar o efeito das frequências de duas e três vezes de exercício por semana sobre biomarcadores de estresse oxidativo no fígado e coração. Foram utilizados 18 camundongos machos (CF1), jovens (30 a 35g) divididos em grupos (n=6/grupo): não treinado (NT); treinado duas vezes por semana (T2) e treinado três vezes por semana (T3). Os animais foram submetidos ao treinamento durante oito semanas. Quarenta e oito horas após a última sessão os animais foram sacrificados. O fígado e o coração foram removidos e armazenados em freezer - 70ºC. Foram analisadas as substâncias reativas ao ácido tiobarbitúrico, carbonilação de proteínas, conteúdo total de tióis, atividades da superóxido dismutase , catalase e glutationa peroxidase. Os resultados demonstraram que apenas o grupo T3 reduziu dano oxidativo. Ademais, houve aumento no conteúdo total de tióis, atividades da superóxido dismutase e catalase no mesmo grupo em comparação com o não treinado. A atividade da glutationa peroxidase não apresentou diferença significativa entre os grupos. Este estudo demonstrou que somente a frequência de treinamento de três vezes por semana reduz dano oxidativo e aumenta a eficiência do sistema enzimático antioxidante de camundongos.

Intense muscle contraction induced by physical exercise increases the production of reactive oxygen species, which causes oxidative stress in several organs, such as the liver and the heart. Physical training may increase antioxidative defenses and decrease oxidative stress. However, it is not clear what training frequency improves oxidative stress parameters. This study evaluated the effect of training two and three times a week on oxidative stress biomarkers in the liver and the heart. Eighteen young male mice (CF1) weighing 30 to 35 g were divided into three groups (n=6): no training (NT); twice a week training (T2); and three times a week training (T3). The training program lasted eight weeks, and the animals were killed 48 hours after the last training session. The liver and the heart were removed and stored at -70o C. The following analyses were conducted: thiobarbituric acid reactive substances, protein carbonylation, total thiol content, superoxide dismutase, catalase and glutathione peroxidase. Oxidative damage was reduced only in the T3 group, and there was an increase in total thiol content, supeoxidase dismutase and catalase in T3 when compared with the NT group. Glutathione peroxidase was not significantly different between groups. Only training three times a week seemed to reduce oxidative stress and increase the efficiency of the antioxidant system in mice.