Weight training increases fat-free mass and strength in untrained young women.
OBJECTIVE
To examine the effects of a weight training program on the resting metabolic rate, fat-free mass, strength, and dietary intake of untrained young women.


METHODS
A 12-week weight training program was completed by 20 previously untrained women aged 19 through 44 years.


METHODS
Twenty-three study subjects and 14 control subjects were recruited on a volunteer basis. Twenty study subjects and 10 control subjects completed the study.


METHODS
Study subjects participated in a 12-week moderate-intensity, progressive resistance weight training program consisting of 2 supervised sessions per week with 6 types of lifting exercises per session. Resting metabolic rate, fat-free mass, strength, and dietary intake were measured before and immediately after the study.


METHODS
Repeated measures analysis of variance and t tests (unequal variance and paired) were used to determine interaction effects and differences within and between groups.


RESULTS
The study group increased their fat-free mass (mean+/-standard deviation) from 44.2+/-5.4 kg to 46.2+/-6.0 kg (P<.001). Elbow flexion, elbow extension, and knee flexion strength all increased from 28.9+/-5.3 to 34.5+/-3.8, 16.9+/-4.9 to 22.1+/-5.3, and 39.5+/-8.6 to 48.6+/-7.3 ft-lb, respectively (P<.001). Percent body fat decreased from 29.8+/-2.8 to 27.2+/-2.6 (P<.001) without a significant change in body weight. Resting metabolic rate did not change significantly (P>.05).


CONCLUSIONS
A moderate-intensity weight training program increased strength and fat-free mass and decreased body fat in normal-weight young women. Favorable changes in body composition were obtained without restricting food intake. The increase in fat-free mass did not increase resting metabolic rate significantly.
Cullinen
K
K
Rhode Island Department of Health, Division of Family Health, Providence 02908, USA.
Caldwell
M
M
D000328:Adult; D001823:Body Composition / Q000502:physiology*; D002153:Calorimetry, Indirect; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D012885:Skinfold Thickness; D014891:Weight Lifting / Q000502:physiology*