Effects of macronutrient intake on thigh muscle mass during home-based walking training in middle-aged and older women.

We examined whether post-exercise macronutrient supplementation during a 5-month home-based interval walking training (IWT) accelerated exercise-induced increases in skeletal muscle mass and strength in healthy middle-aged and older women. Thirty-five women (41-78 years) were randomly divided into two groups: IWT alone (CNT, n = 18) or IWT plus post-exercise macronutrient (7.6 g protein, 32.5 g carbohydrate, and 4.4 g fat) supplementation (NUT, n = 17). For IWT, all subjects were instructed to repeat five or more sets of 3-min low-intensity walking at 40% peak aerobic capacity (Vo2 peak ), followed by a 3-min high-intensity walking above 70% Vo2 peak per day for 4 or more days per week. We determined Vo2 peak , thigh muscle tissue area by computer tomography, and thigh muscle strength in all subjects before and after IWT. We found that an increase in hamstring muscle tissue area was 2.8 ± 1.2% in NUT vs -1.0 ± 0.7% in CNT and that in isometric knee flexion force was 16.3 ± 3.7% in NUT vs 6.5 ± 3.0% in CNT; both were significantly higher in NUT than in CNT (both, P < 0.001). Thus, post-exercise macronutrient supplementation enhanced the increases in thigh muscle mass and strength, although partially, in home-based IWT in middle-aged and older women.

Physical fitness and indices of lifestyle-related diseases before and after interval walking training in middle-aged and older males and females.

HYPOTHESIS: Whether increasing peak aerobic capacity for walking (VO(2peak)) by interval walking training (IWT) is closely linked with decreasing the indices of lifestyle-related diseases (LSDs) in middle-aged and older people were examined. METHODS: For 4 months from April to September 2005 or 2006, 246 males and 580 females (∼65 years) performed IWT consisting of ≥5 sets of fast walking at ≥70% VO(2peak) for 3 min followed by slow walking at ≤40% VO(2peak) for 3 min ≥4 days/week. Before and after IWT, we measured VO(2peak), body mass index (BMI), %body fat, arterial blood pressure, thigh muscle strength and blood parameters. We analysed 198 males and 468 females who had undergone all the measurements both before and after IWT. To examine the hypothesis, we divided the subjects equally into three groups according to their pretraining VO(2peak): low, middle and high groups for each sex. RESULTS: Before training, it was found that thigh muscle strength and blood high-density lipoprotein cholesterol concentration were lower, whereas body weight, BMI, %body fat, arterial blood pressure and blood glucose were higher in the low group than the high group (all, p<0.05). After training, although VO(2peak) and thigh muscle strength increased and body weight, BMI, %body fat, blood pressure and blood glucose concentration decreased in all groups (all, p<0.05), the changes were greatest in the low group for both sexes. CONCLUSION: VO(2peak) at baseline and changes in response to training were closely linked with indices of LSDs.