Musculoskeletal responses to high- and low-intensity resistance training in early postmenopausal women.
OBJECTIVE
The purpose of this study was to compare the effects of a high-load (80%, 1-repetition maximum (RM), 8 reps) and a high-repetition (40%, 1-RM, 16 reps) resistance training protocol on muscular strength and bone mineral density (BMD) in early postmenopausal, estrogen-deficient women. The 6-month programs were matched initially for training volume (3 sets, 3 d x wk(-1)) for 12 exercises selected to specifically load the spine and hip.


METHODS
Subjects included 25 women (41-60 yr) who were matched by spine BMD then randomly assigned to either the high-load (HL, N = 10), high-repetition (HR, N = 7), or control (C, N = 8) groups. Dietary calcium intakes were supplemented to approximately 1500 mg x d(-1). Total body, spine, and hip BMD (DXA, Lunar Model DPX-IQ), upper and lower body muscular strength, and biochemical markers of bone turnover were measured at baseline and after 6 months of training.


RESULTS
There were no group differences in the baseline measures. Both training groups showed similar increases in biceps (20%) and rectus femoris (28-33%) cross-sectional areas, in lower body strength (approximately 30%) and in hip strength (37-40%). HL showed greater improvements in upper body strength (HL 25%, HR 16%). Neither training group experienced significant increases in spine or hip BMD, although the HL total body BMD tended to decrease (-1.1%+/-0.4, P = 0.054) after training. Osteocalcin tended to increase (P = 0.08) in all groups after training, and the % change in osteocalcin was positively related to % changes in the total hip (r = 0.41, P = 0.048) and the trochanter (r = 0.42, P = 0.04) BMD.


CONCLUSIONS
The high-load and high-repetition resistance training protocols were both effective in improving muscular strength and size in postmenopausal women, indicating low-intensity resistance training can be beneficial for the muscular fitness in women for whom high-intensity exercise is contraindicated.
Bemben
D A
DA
Department of Health and Sport Sciences, University of Oklahoma, Norman 73019, USA. dbemben@ou.edu
Fetters
N L
NL
Bemben
M G
MG
Nabavi
N
N
Koh
E T
ET
D000328:Adult; D001823:Body Composition; D015519:Bone Density; D002136:Calcium, Dietary / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D015675:Osteocalcin / Q000097:blood; D010809:Physical Fitness / Q000502:physiology*; D017698:Postmenopause / Q000502:physiology*
D002136:Calcium, Dietary; D015675:Osteocalcin