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The effects of 8 weeks voluntary wheel running on the contractile performance of isolated locomotory (soleus) and respiratory (diaphragm) skeletal muscle during early ageing.Decreased skeletal muscle performance with increasing age is strongly associated with reduced mobility and quality of life. Increased physical activity is a widely prescribed method of reducing the detrimental effects of ageing on skeletal muscle contractility. The present study uses isometric and work loop testing protocols to uniquely investigate the effects of 8 weeks of voluntary wheel running on the contractile performance of isolated dynapenic soleus and diaphragm muscles of 38 week old CD1 mice. When compared to untrained controls, voluntary wheel running induced significant improvements in maximal isometric stress and work loop power, a reduced resistance to fatigue, but greater cumulative work during fatiguing work loop contractions in isolated muscle. These differences occurred without appreciable changes in LDH, CS, SERCA or MHC expression synonymous with this form of training in younger rodent models. Despite the given improvement in contractile performance, the average running distance significantly declined over the course of the training period, indicating that this form of training may not be sufficient to fully counteract the longer term ageing induced decline in skeletal muscle contractile performance. Although these results indicate that regular low intensity physical activity may be beneficial in offsetting the age-related decline in skeletal muscle contractility, the present findings infer that future work focusing on the maintenance of a healthy body mass with increasing age and its effects on myosin-actin cross bridge kinetics and Ca(2+) handling, is needed to clarify the mechanisms causing the improved contractile performance in trained dynapenic skeletal muscle.
A pilot study evaluating the effects of a 12 week exergaming programme on body mass, size and composition in postpartum females.Introduction: Pregnancy is associated with weight gain, the retention of which contributes to the prevalence of obesity and overweight in adult females. Many new mothers do not achieve the recommendations for physical activity (PA), citing factors such as a lack of time and access to childcare. Exergaming may address some of the barriers to PA and offer an alternative to traditional exercise, thus aiding in weight management. The aim of this pilot study was to evaluate the effects of an exergaming intervention on body composition in postpartum females. Methods: Eight females who had given birth within 1 year completed a 12 week exergaming intervention, which required them to exercise at home for 45 minutes on alternate days, using the Wii Fit. Participants self-reported their pre-pregnancy body weight, and visited the laboratory prior to and following the intervention for evaluation of body weight, size (height, regional circumferences, body mass index [BMI]) and composition (fat mass [FM], lean mass [LM] and bone mineral content [BMC]). Body composition was evaluated via full body full-body dual-energy x-ray absorptiometry scan. Participants completed a three-day weighed food intake at three time-points. Results: Baseline body mass was 8.2 kg greater than self-reported pre-pregnancy values (56.8 ± 5.1 kg). Following the intervention, body mass was significantly lower than baseline values and was similar to pre-pregnancy levels (59.9 ± 7.9 kg). Reductions in BMI (~2 kg·m2), waist, hip and bust circumference (3-6%) accompanied the loss of body mass. Food diaries confirmed participants had not altered their energy intake. Discussion: The results of this pilot study indicate that exergaming may offer an alternative to traditional exercise for preventing the retention of gestational weight gain and reducing associated health risks, whilst also maintaining lean mass and bone mineral content.