Effect of resistance exercise on bone mineral density in premenopausal women.
OBJECTIVE
To assess the effect of 9 months of strength training on total body and regional bone mineral density (BMD, g/cm(2)) in 58 premenopausal women aged 30-50 years.


METHODS
Participants were randomized to either twice weekly supervised strength training for 15 weeks followed by 24 weeks of unsupervised training (treatment group) or control group. Height, weight, maximal muscular strength, nutrient intake and physical activity were assessed. Total body dual energy X-ray absorptiometry (DXA, Lunar Prodigy) scans were taken and analyzed for body composition (lean and fat mass), and BMD for total body and its sub-regions (spine, hip, arms and legs). All measurements were performed at baseline, 15 and 39 weeks. Analysis of covariance was used to assess group differences in BMD change adjusted for baseline BMD, weight, energy and calcium intake.


RESULTS
At baseline, the two groups had similar BMD and body size characteristics ( P<0.05 for all), except that the treatment group had lower body weight (-7.1 kg), and higher energy (+259 kJ/d) and calcium (+232 mg/d) intake at baseline. Adjusted % change in BMD over 15 weeks (0.5% vs. 0.4%) or 39 weeks (0.9% vs. 1.2%) did not differ significantly between the exercise and control groups, respectively. The exercise group increased BMD at the spine and legs (1-2.2%), while there was no change in the controls, but differences between groups were not significant.


CONCLUSIONS
Strength training over 9 months did not lead to significantly greater change in total body or regional BMD in premenopausal women.
Singh
Jasvinder A
JA
Minneapolis VA Medical Center, Rheumatology, One Veterans Drive, Minneapolis, 55417 MN, USA. jasvinder.md@gmail.com
Schmitz
Katherine H
KH
Petit
Moira A
MA
D015502:Absorptiometry, Photon; D000328:Adult; D001823:Body Composition; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000378:metabolism*; D002136:Calcium, Dietary; D002149:Energy Intake / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D017697:Premenopause / Q000502:physiology*; D011795:Surveys and Questionnaires
D002136:Calcium, Dietary