Fitness and energy expenditure after strength training in obese prepubertal girls. Med. Sci. Sports Exerc., Vol. 30, No. 7, pp. 1130-1136, 1998.
Purpose: The purpose of this study was to determine the effects of a school-based, low-volume strength training program on energy expenditure, strength, and physical fitness in obese prepubertal girls.
Methods: A longitudinal, 5-month strength training exercise program was undertaken by healthy, obese (>95th percentile weight-for-height, N = 11) girls age 7-10 yr. The following were measured: strength by the one-repetition maximum test; fitness (V˙O2peak) by a treadmill exercise test; resting metabolic rate (RMR), 24-h sedentary energy expenditure (SEE), and sleeping metabolic rate (SMR) by room respiration calorimetry; and total energy expenditure (TEE) by the doubly labeled water method. Physical activity energy expenditure (AEE) was calculated as TEE - (RMR + 0.1*TEE) and physical activity level (PAL) as TEE/RMR. An age-matched, nonoverweight control group was measured for V˙O2peak and RMR over the same time period.
Results: Strength increased by 19.6 and 20.0% in the upper and lower body (P < 0.01), respectively. V˙O2peak (mL·min−1) increased in both groups over time (P < 0.05), but not when covaried for fat-free mass (FFM) or weight. After adjusting for FFM or weight, RMR did not change, but SMR and 24-h SEE decreased significantly in the exercise group. There were no changes in nonprotein respiratory quotient or substrate oxidation. No changes in TEE, AEE, and PAL occurred, either unadjusted or adjusted for FFM or weight.
Conclusion: This long-term, school-based, low-volume strength training program favorably increases strength in obese prepubertal girls but does not increase their daily energy expenditure.
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030; and Department of Nutrition Science, Energy, Metabolism Research Unit and Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294
Submitted for publication March 1997.
Accepted for publication October 1997.
The authors thank the children from Tarrant Elementary for participating in the exercise study, and B. Petri and H. Vaughn for technical assistance. This study was supported by GCRC Grant M01-RR00032 and R29 Grant HD 34029 (to M.T.), a University of Alabama at Birmingham School of Education grant (to M.T. and G.H.), Grant DK 02244 (to R.F.-C.), and USDA and R29 Grant HD 32668 (to M.I.G.).
Address for correspondence: Margarita S. Treuth, Ph.D., USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street, Houston, TX 77030. e-mail: firstname.lastname@example.org.