Search

Purpose was determine effects resistance training/weight loss induced changes in muscular strength and flexibility have on net walking oxygen uptake (netVO2). Sixty-seven premenopausal women lost 12 kg. Before weight loss subjects were assigned to diet (WL) or diet/3 days per week resistance training (WLRT). Resting energy expenditure, oxygen uptake while walking at 4.84 km h−1 on the flat and up 2.5% grade, isometric knee extension strength, and flexibility of the knee extensors and plantar flexors were measured. Strength increased in WLRT (+36 N) but not in WL (−24 N). NetVO2 decreased significantly while flat walking (7.3%) and 2.5% grade walking (5.7%) in WLRT, but not in WL. Delta strength was negatively while delta knee extensor and plantar flexor flexibility were positively related to delta netVO2. Decreases in walking and grade netVO2 were independently and positively related to increased knee extension strength and decreased knee extensor and plantar flexor flexibility.

Objective: To determine what effect diet-induced 12 kg weight loss in combination with exercise training has on body composition and resting energy expenditure (REE) in premenopausal African-American (AA) and European-American (EA) women.--- Methods and Procedures: This study was a longitudinal, randomized weight loss clinical intervention, with either aerobic (AT), resistance (RT), or no exercise training (NT). Forty-eight AA and forty-six EA premenopausal overweight (BMI between 27 and 30) women underwent weight loss to a BMI <25. Body composition (densitometry), REE (indirect calorimetry), maximal oxygen uptake (VO2max), and muscular strength (isometric elbow flexion) were evaluated when subjects were in energy balance.--- Results: AA women lost less fat-free mass (FFM, P 0.05) (47.0 4.6 to 46.9 5.0 kg) than EA women (46.4 4.9 to 45.2 4.6 kg). Regardless of race, RT maintained FFM (P 0.05) following weight loss (46.9 5.2 to 47.2 5.0 kg) whereas AT (45.4 4.2 to 44.4 4.1 kg) and NT (47.9 4.7 to 46.4 5.1 kg) decreased FFM (P 0.05). Both AT and NT decreased in REE with weight loss but RT did not. Significant time by group interactions (all P 0.05) for strength indicated that RT maintained strength and AT did not.--- Discussion: AA women lost less FFM than EA women during equivalent weight losses. However, following weight loss in both AA and EA, RT conserved FFM, REE, and strength fitness when compared to women who AT or did not train.

Background: Little is known about the effect of weight change on regional lean body mass (LBM) distribution or on racial differences in resting metabolic rate (RMR). Objective: The study compared total and regional LBM patterns in white and black women after weight loss and regain and assessed the influence of regional LBM on variances in RMR. Design: Eighteen white and 22 black women who did not differ in age, weight, and height were studied 3 times: in the overweight state, after weight reduction to the normal-weight state, and after 1 y without intervention. Total and regional lean and fat masses were assessed by dual-energy X-ray absorptiometry. Results: White and black women did not differ significantly in mean (± SD) weight loss (13.4 ± 3.6 and 12.7 ± 3.2 kg, respectively) and regain (6.1 ± 5.5 and 6.4 ± 5.4 kg, respectively). Black subjects had significantly less trunk LBM and significantly more limb LBM at each time point (P < 0.05). In both races, weight regain was associated with significant increases in limb LBM (P < 0.05) but not in trunk LBM (P = 0.21). RMR, adjusted for total LBM and fat mass, was significantly higher in white women after weight loss (P < 0.01) and regain (P < 0.01). However, no racial difference was found when RMR was adjusted for LBM distribution. Conclusions: In both races, trunk LBM decreased with weight loss and remained lower, despite significant weight regain, which potentially reflected decreased organ mass. Regional LBM distribution explained the racial difference in RMR.

Background: Although physical inactivity is believed to contribute to the rising prevalence of obesity, the role and magnitude of its contribution to weight gain are unknown. Objective: We compared total free-living activity energy expenditure (AEE) and physical activity level in women successful and unsuccessful at maintaining a normal body weight. Design: Premenopausal, generally sedentary women were studied at their normal weight and 1 y later after no intervention. Two groups were identified on the basis of extreme weight changes: maintainers (n = 27) had a weight gain of 3% of their initial body weight ( 2 kg/y) and gainers (n = 20) had a weight gain of >10% (>6 kg/y). At baseline and follow-up, evaluations were conducted during 4 wk of diet-controlled, energy-balance conditions. Free-living AEE and physical activity were assessed with the use of doubly labeled water, exercise energy economy and muscle strength with the use of standardized exercise tests, and sleeping EE and substrate utilization with the use of chamber calorimetry. Results: Maintainers lost a mean (±SD) of 0.5 ± 2.2 kg/y and gainers gained 9.5 ± 2.1 kg/y. Gainers had a lower AEE (P < 0.02), a lower physical activity level (P < 0.01), and less muscle strength (P < 0.001); these differences between groups remained significant from baseline to follow-up. Sleeping EE, exercise economy, and sleeping or 24-h substrate utilization were not significantly different between the 2 groups. A lower AEE in the gainers explained 77% of their greater weight gain after 1 y. Conclusion: The general US population should increase their daily physical activity levels to decrease the rising prevalence of obesity.

The Production Automation Project was established in mid-1972 with NSF/RANN support. The Project's initial mandate covered part programming systems for manufacturing automation of a higher order than those currently available, plus such related topics as industrial graphic systems. Our first task was to define the task(s) more concretely. As part of that effort, we surveyed four areas of technology: computer graphics, industrial graphic systems, part programming languages and systems, and NC controller technology. The survey data proved very difficult to evaluate for a very fundamental reason: there is no acknowledged set of scientific principles -- no "theory of manufacturing" -- to say how such systems "should" work. We set out to build such a theory, and to write a report, TR-1, setting forth both the theory and the survey results.

The Production Automation Project was established in mid-1972 with NSF/RANN support. The Project's initial mandate covered part programming systems for manufacturing automation of a higher order than those currently available, plus such related topics as industrial graphic systems. Our first task was to define the task(s) more concretely. As part of that effort, we surveyed four areas of technology: computer graphics, industrial graphic systems, part programming languages and systems, and NC controller technology. The survey data proved very difficult to evaluate for a very fundamental reason: there is no acknowledged set of scientific principles -- no "theory of manufacturing" -- to say how such systems "should" work. We set out to build such a theory, and to write a report, TR-1, setting forth both the theory and the survey results.