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The aims of this study were to describe age- and sex-related differences in total body skeletal muscle (TB-SM) mass and to determine the variance explained by physical activity (PA). This cross-sectional study included 401 males and 402 females, aged 60–79 years. TB-SM was determined by dual-energy x-ray absorptiometry (DXA) and PA by Baecke questionnaire. Statistical analysis included t test, ANOVAs, Pearson correlations, and multiple regression analysis. TB-SM mass was higher in the youngest age group when compared with the oldest in males and females. Males had greater TB-SM values than females. PA made a significant and positive contribution to the variation in TB-SM, β = 0.071; p = .016. Sex, height, fat mass, and PA explained 77% of the variance in TB-SM. The oldest cohorts and females had lower TB-SM than the younger cohorts and males. This study suggests that PA exerts a significant role in the explanation of TB-SM. [ABSTRACT FROM AUTHOR]

The purposes of this study were to generate functional-fitness norms for Portuguese older adults, to determine age and sex differences, and to analyze the physical activity-associated variation in functional fitness. The sample was composed of 802 older adults, 401 men and 401 women, age 60-79 yr. Functional fitness was assessed using the Senior Fitness Test. Physical activity level was estimated via the Baecke questionnaire. The P50 values decreased from 60 to 64 to 75 to 79 yr of age. A significant main effect for age group was found in all functional-fitness tests. Men scored significantly better than women in the chair stand, 8-ft up-and-go, and 6-min walk. Women scored significantly better than men in chair sit-and-reach and back scratch. Active participants scored better in functional-fitness tests than their average and nonactive peers. This study showed a decline in functional fitness with age, better performance of men, and increased proficiency in active participants. [ABSTRACT FROM AUTHOR]

Few studies have explored osteogenic potential of prepubertal populations. We conducted a 28-week school-based exercise trial of single-leg drop-landing exercise with 42 prepubertal girls (6 to 10 yrs) randomly assigned to control (C), low-drop (LD) or high-drop (HD) exercise groups. The latter two groups performed single-leg drop-landings (3 sessions/wk-1 and 50 landings/session-1) from 14cm(LD) and 28cm(HD) using the nondominant leg. Osteogenic responses were assessed using Dual Energy X-ray Absorptiometry (DXA). Single-leg peak ground-reaction impact forces (PGRIF) in a subsample ranged from 2.5 to 4.4 × body-weight (BW). No differences (p > .05) were observed among groups at baseline for age, stature, lean tissue mass (LTM), leisure time physical activity, or average daily calcium intake. After adjusting for covariates of body mass, fat mass and LTM, no differences were found in bone mineral measures or site-specific bone mineral density (BMD) at the hip and lower leg among exercise or control groups. Combining data from both exercise groups failed to produce differences in bone properties when compared with the control group. No changes were apparent for between-leg differences from baseline to posttraining. In contrast to some reports, our findings suggest that strictly controlled unimodal, unidirectional single-leg drop-landing exercises involving low-moderate peak ground-reaction impact forces are not osteogenic in the developing prepubertal female skeleton. [ABSTRACT FROM AUTHOR]

Postulates that the high salt content in the sweat of cystic fibrosis (CF) patients and the consequent absence of body-fluid hyperosmolality during a long episode of sweating might deprive such patients of a thirst stimulus. Conclusion that children with CF underestimate their fluid needs; Problems with excessive dehydration during extended exposure to hot conditions; Patients and methods; Results; Discussion.

Relationships among nutritional status and skeletal and respiratory muscle function were examined in 16 children with cystic fibrosis (CF) and mild lung disease (FEV, 95 ± 16% predicted). Subjects were randomly assigned to receive (or not) noninvasive nutritional supplementation at 25% of normal energy recommendations for 6 mo. Skeletal muscle strength and power were similar to those of healthy children as were respiratory muscle strength and endurance. Stepwise-regression analysis indicated that changes in skeletal muscle strength and energy intake correlated significantly with growth [weight (kg) = 1.90 - 0.60 (Tanner Stage) + 0.49 (maximum voluntary strength (Nm) + 0.03 (energy intake, % RNI), r = 0.76, P < 0.05], though body composition, protein biochemistry, muscle power, respiratory muscle strength, and use of dietary supplements did not. Thus, changes in skeletal muscle strength may be a functional index of changes in nutritional status in CF. Dietary supplementation per se was not associated with functional improvement. [ABSTRACT FROM AUTHOR]

Objectives: To review the effects of physical activity on health and behavior outcomes and develop evidence-based recommendations for physical activity in youth., Study Design: A systematic literature review identified 850 articles; additional papers were identified by the expert panelists. Articles in the identified outcome areas were reviewed, evaluated and summarized by an expert panelist. The strength of the evidence, conclusions, key issues, and gaps in the evidence were abstracted in a standardized format and presented and discussed by panelists and organizational representatives., Results: Most intervention studies used supervised programs of moderate to vigorous physical activity of 30 to 45 minutes duration 3 to 5 days per week. The panel believed that a greater amount of physical activity would be necessary to achieve similar beneficial effects on health and behavioral outcomes in ordinary daily circumstances (typically intermittent and unsupervised activity)., Conclusion: School-age youth should participate daily in 60 minutes or more of moderate to vigorous physical activity that is developmentally appropriate, enjoyable, and involves a variety of activities.