The effects of a 12-week resistance training programme on the body composition and resting metabolic rate in a cohort of caucasian and coloured, premenopausal women aged 25-35 years

Abstract

Resting metabolic rate (RMR) is the largest component of daily energy expenditure, with lower values in the black population. Resistance training is considered to be the most effective exercise modality to increase fat-free mass (FFM), and therefore also the RMR. The objective of this study was to determine the effect of a 12-week resistance training programme on the body composition (FFM, FM) and resting metabolic rate (RMR) in a cohort of South African premenopausal women. An available sample of Caucasian (n = 20) and Coloured women (n = 8) between ages 25 and 30 years completed a 12-week intervention study. Body composition (FFM, FM) and RMR were determined by using the Bod Pod^® together with other anthropometric measurements (body mass, stature and waist circumference). Statistical analysis included the Mann-Whitney U test as well as the effect size, to determine the significance of the intervention regimen. No statistically significant differences occurred but medium practically significant differences were found between the groups. Coloured women had a greater decrease in body mass (r = 0.25), FM (r = 0.28) and increase in RMR (r = 0.28) than the Caucasians. Both groups showed a decrease in body mass, FM, percentage body fat, waist circumference, body mass index (BMI) and an increase in FFM and RMR after the intervention programme. In conclusion, it therefore seems that a resistance intervention programme can serve as an effective tool in increasing FFM and RMR, which may inter alia be associated with a decrease in FM, percentage body fat and body mass among both groups of premenopausal women.

Keywords: Resistance training, body composition, fat-free mass (FFM), fat mass (FM), resting metabolic rate (RMR).