Background/Purpose: Previous randomized controlled trials have led to conflicting findings regarding the effects of ground and/or joint reaction force exercise on femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD) in postmenopausal women. The purpose of this study was to use the aggregate data meta-analytic approach to resolve these discrepancies.
Methods: The a priori inclusion criteria were: (1) randomized controlled trials, (2) ground and/or joint reaction force exercise > 24 weeks, (3) comparative control group, (4) postmenopausal women, (5) participants not regularly active, (6) published and unpublished studies in any language since January 1, 1989, (7) BMD data available at the FN and/or LS. Studies were located by searching six electronic databases, cross-referencing, hand searching and expert review. Dual selection of studies and data abstraction were performed. Hedge’s standardized effect size (g) was calculated for each FN and LS BMD result and pooled using random-effects models. Z-score alpha values, 95% confidence intervals (CI) and number-needed-to-treat (NNT) were calculated for pooled results. Heterogeneity was examined using Q and I2. Mixed-effects ANOVA and simple meta-regression were used to examine changes in FN and LS BMD according to selected categorical and continuous variables. Statistical significance was set at an alpha value ≤ 0.05 and a trend at >0.05 to ≤ 0.10.
Results: Statistically significant exercise minus control group improvements were found for both FN (28 g’s, 1632 participants, g = 0.288, 95% CI = 0.102, 0.474, p = 0.002, Q = 90.5, p<0.0001, I2 = 70.1%, NNT = 6) and LS (28 g’s, 1504 participants, g = 0.179, 95% CI = -0.003, 0.361, p = 0.05, Q = 77.7, p<0.0001, I2= 65.3%, NNT = 6) BMD. None of the mixed-effects ANOVA analyses were statistically significant. For both FN and LS BMD, statistically significant, or a trend for statistically significant and positive associations were observed for intensity of training and compliance (joint reaction force exercise only) as well as changes in static balance. Inverse associations were observed for compliance (combined ground and joint reaction force exercise) as well as changes in body mass index, body weight and percent body fat. When limited to the LS, statistically significant, or a trend for statistically significant and positive associations were found for age, years postmenopausal and changes in lean body mass while inverse associations were observed for duration of training (minutes per session, ground reaction force exercise only), total minutes of training per week (ground reaction force exercise only), compliance (combined ground and joint reaction force exercise) and changes in aerobic fitness.
Conclusion: Exercise benefits FN and LS BMD in postmenopausal women. Several of the observed associations appear worthy of further investigation in well-designed randomized controlled trials.
Disclosure:
G. A. Kelley,
None;
K. S. Kelley,
None;
W. M. Kohrt,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/effects-of-ground-and-joint-reaction-force-exercise-on-bone-mineral-density-in-postmenopausal-women-a-meta-analysis-of-randomized-controlled-trials/