Weight lifted in strength training predicts bone change in postmenopausal women.
OBJECTIVE
The aim of this study was to examine the relationship between weight lifted in 1 yr of progressive strength training and change in bone mineral density (BMD) in a group of calcium-replete, postmenopausal women.


METHODS
As part of a large clinical trial, 140 calcium-supplemented women, 44-66 yr old, were randomized to a 1-yr progressive strength-training program. Half of the women were using hormone replacement therapy. Three times weekly, subjects completed two sets of six to eight repetitions in eight core exercises at 70-80% of one repetition maximum. BMD was measured at baseline and 1 yr.


RESULTS
In multiple linear regression, the increase in femur trochanter (FT) BMD was positively related to total weight lifted (0.001 g.cm (-2)) for a SD of weight lifted, P< 0.01) after adjusting for age, baseline factors, HRT status, weight change, cohort, and fitness center. The weighted squats showed the strongest (0.002 g.cm(-2)) for a SD of weight lifted, P< 0.001), whereas the back extension exhibited the weakest (0.0005 g.cm(-2)) for a SD of weight lifted, P< 0.26) association with change in FT BMD. The amount of weight lifted in the weighted march exercise was significantly related to total body BMD (0.0006 g.cm(-2)) for a SD of weight lifted, P< 0.01). The associations between weight lifted and BMD for the femur neck or lumbar spine were not significant.


CONCLUSIONS
Evidence of a linear relationship between BMD change and total and exercise-specific weight lifted in a 1-yr strength-training program reinforces the positive association between this type of exercise and BMD in postmenopausal women.
Cussler
Ellen C
EC
Department of Physiology, Faculty of Human Movement, Technical University of Lisbon, Portugal.
Lohman
Timothy G
TG
Going
Scott B
SB
Houtkooper
Linda B
LB
Metcalfe
Lauve L
LL
Flint-Wagner
Hilary G
HG
Harris
Robin B
RB
Teixeira
Pedro J
PJ
D015502:Absorptiometry, Photon; D015519:Bone Density; D005260:Female; D005269:Femur / Q000502:physiology; D005272:Femur Neck / Q000502:physiology; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D014891:Weight Lifting / Q000502:physiology*