Scott B Going

PMID: 8422204;Abstract:

Background: Aerobic exercise training is associated with reduced serum concentrations of triglycerides, increased concentrations of high-density lipoprotein cholesterol, and minimal changes in serum levels of total cholesterol or low-density lipoprotein cholesterol. There are few data on the effects of resistance exercise on blood lipid levels. Methods: Premenopausal women were randomly assigned to a supervised resistance exercise training program (n=46) or a control group (n=42) for 5 months. Serum was analyzed for levels of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. Body composition and dietary intake were also measured. Results: The exercise group showed a 0.33±0.03-mmol/L (mean±SE) decrease in total cholesterol level and a 0.36±0.001-mmol/L decrease in low-density lipoprotein cholesterol level that was significantly different from the control group. No significant changes were noted in serum high-density lipoprotein cholesterol or triglyceride levels in either group. Changes in body composition showed no significant correlations with changes in total cholesterol or low-density lipoprotein cholesterol. There were no significant differences in nutrient intake between the groups. Conclusion: In healthy, premenopausal women, with normal baseline lipid profiles, 5 months of resistance exercise training was associated with significant decreases in serum total cholesterol and low-density lipoprotein cholesterol concentrations.

PMID: 23698240;PMCID: PMC3833884;Abstract:

INTRODUCTION: Poor muscle quality and sedentary behavior are risk factors for metabolic dysfunction in children and adolescents. However, because longitudinal data are scarce, relatively little is known about how changes in muscle quality and physical activity influence bone development. PURPOSE: In a 2-yr longitudinal study, we examined the effects of physical activity and changes in muscle quality on bone parameters in young girls. METHODS: The sample included 248 healthy girls age 9-12 yr at baseline. Peripheral quantitative computed tomography was used to measure calf and thigh muscle density, an indicator of skeletal muscle fat content or muscle quality, as well as bone parameters at diaphyseal and metaphyseal sites of the femur and tibia. Physical activity was assessed using a validated questionnaire specific for youth. RESULTS: After controlling for covariates in multiple regression models, increased calf muscle density was independently associated with greater gains in cortical (β = 0.13, P 0.01) and trabecular (β = 0.25, P 0.001) volumetric bone mineral density and the bone strength index (β = 0.25, P 0.001) of the tibia. Importantly, these relationships were generalized, as similar changes were present at the femur. Associations between physical activity and changes in bone parameters were weaker than those observed for muscle density. Nevertheless, physical activity was significantly (all P 0.05) associated with greater gains in trabecular volumetric bone mineral density and the bone strength index of the distal femur. CONCLUSIONS: These findings suggest that poor muscle quality may put girls at risk for suboptimal bone development. Physical activity is associated with more optimal gains in weight-bearing bone density and strength in girls, but to a lesser extent than changes in muscle quality. Copyright © 2013 by the American College of Sports Medicine.

PMID: 12885714;Abstract:

Background: Nationwide data on obesity prevalence in American Indian communities are limited. Objective: We describe the body composition and anthropometric characteristics of schoolchildren from 7 American Indian communities enrolled in the Pathways study, a randomized field trial evaluating a program for the primary prevention of obesity. Design: A total of 1704 children in 41 schools were enrolled in the study. Basic anthropometric measurements included weight, height, and triceps and subscapular skinfold thicknesses. Percentage body fat was estimated from bioelectrical impedance and anthropometric variables with the use of an equation developed and validated for this population. Results: The children's mean (± SD) age was 7.6 ± 0.6 y, and their mean weight and height were 32.1 ± 8.9 kg and 129.8 ± 6.3 cm, respectively. Mean body mass index (BMI; in kg/m ²) was 18.8 ± 3.9, and mean percentage body fat was 32.6 ± 6.8%. With the use of current Centers for Disease Control and Prevention reference values, 30.5% of girls and 26.8% of boys were above the 95th percentiles for BMI-for-age, and 21% of girls and 19.6% of boys were between the 85th and 95th percentiles. Although there was a wide range in BMI across study sites and for both sexes, the percentage of children with a BMI above the 95th percentile was consistently higher than the national averages in all communities studied and in both girls and boys. Conclusions: Overweight can be documented in a substantial number of American Indian children by the time they reach elementary school. Despite differences in the prevalence of overweight observed among communities, rates are uniformly high relative to national all-race averages.