Show simple item record McCracken, Colleen M. 2010-01-05T18:47:37Z 2010-01-05T18:47:37Z 2009-12
dc.description.abstract PROBLEM: It is generally concluded that muscle mass declines with increasing age. Most of the research in this area is focused on the general population which is largely sedentary. The purpose of this study was to examine the muscle mass of highly active adults using several independent methods. METHODS: 167 women aged 50.91 +/- 14.03 yrs and 219 men aged 52.08 +/- 13.45 yrs underwent body composition analysis via 8-lead bioelectric impedance analysis, anthropometric measurements to assess limb circumference, and 24 hour creatinine clearance. Comparative data for the general population (GP) was obtained from the Baltimore Longitudinal Study of Aging, National Health and Nutrition Examination Survey III and The American College of Sports Medicine and Center for Disease Control recommended physical activity guidelines. Highly active subjects were all masters swimmers and a priori categorized as highly active (USMS). To verify this, the USMS were found to participate in 447 min/wk of moderate to vigorous physical activity which was much greater than 150 min/wk reported for the GP. ANALYSIS: Muscle mass was the primary the dependent variable. Single sample t-tests were used to examine muscle mass differences between groups separated by age and sex. Linear regression analysis was used to describe the trend of muscle mass versus age. RESULTS: USMS women had more muscle mass than GP in the 30-39, 40-49, 50-59, 60-69, & 70-79 age groups. Y-intercepts were significantly (p < .05) different for both sexes between the highly active and general population. No significant differences were found for between men v USMS and GP in 30-39, 40-49, 50-59, & 80 + age groups. Linear regression analysis of the USMS men and women yielded losses of approximately 0.3 lbs per year. DISCUSSION: Highly active subjects participated in significantly greater amounts of dedicated physical activity per week when compared to values available for the general population (NHANES III). Comparisons of the muscle mass slopes yielded no differences between the GP and the USMS. Muscle mass loss occurs at similar rates in both populations. Importantly, and specifically, in the USMS women, muscle mass is greater any given age. However, this was not true for the USMS men. Intensive activity may combat many problems associated with losses in muscle mass, especially those within older women. Why this is not evident in the men requires additional research. en
dc.description.sponsorship Submitted to the Faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Science in the Department of Kinesiology of the School of Health, Physical Education, and Recreation Indiana University December 2009 en
dc.language.iso en_US en
dc.subject body composition analysis en
dc.subject muscle mass en
dc.title Muscle Mass Loss in Active Adults en
dc.type Thesis en

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