Effects of Exercise Involving Predominantly Either Joint-Reaction or Ground-Reaction Forces on Bone Mineral Density in Older Women

Abstract

This study compared the effects of two exercise training programs, 11 months in duration, on bone mineral density (BMD) in older, sedentary women. Thirty-nine women, aged 60 -74 years, were assigned to the following groups: (a) a group that performed exercises that introduced stress to the skeleton through ground-reaction forces (GRF) (i.e., walking, jogging, stairs); (b) a group that performed exercises that introduced stress to the skeleton through joint-reaction forces (JRF) (i.e., weight lifting, rowing); or (c) a no-exercise control group. BMD of the whole body, lumbar spine, proximal femur, and distal forearm was assessed five times at ϳ ϳ3-month intervals. The GRF and JRF exercise programs resulted in significant and similar increases in BMD of the whole body (2.0 ؎ 0.8% and 1.6 ؎ 0.4%, respectively), lumbar spine (1.8 ؎ 0.7% and 1.5 ؎ 0.5%, respectively), and Ward's triangle region of the proximal femur (6.1 ؎ 1.5% and 5.1 ؎ 2.1%, respectively). There was a significant increase in BMD of the femoral neck only in response to the GRF exercise program (GRF, 3.5 ؎ 0.8%; JRF, ؊0.2 ؎ 0.7%). There were no significant changes in BMD in control subjects. Among all exercisers, there was a significant inverse (r ‫؍‬ ؊0.52, p < 0.01) relationship between increases in whole body BMD and reductions in fat mass, suggesting a dose response effect of exercise on bone mass. Although femoral neck BMD was responsive only to the GRF exercise program, some adaptations (i.e., increase in lean body mass and strength) that were specific to the JRF exercise program may be important in preventing osteoporotic fractures by reducing the risk for falls. It remains to be determined whether all of these benefits can be gained through a training program that combines the different types of exercises employed in this

The role of physical activity in producing and maintaining weight loss

“…Sixteen RCTs [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] were identified that had compared weight loss in groups assigned physical activity alone with that in groups assigned no intervention. A summary of the findings of these RCTs is included in Table 1.…”

“…Of the 16 RCTs, 11 found statistically significant improvements in weight loss with exercise compared with controls. 2,3,[5][6][7][9][10][11]13,16,17 The magnitude of the differences in weight outcomes between groups in these studies was small. Weight loss in the exercise group ranged from 0.1 kg to 5.2 kg, with most studies showing weight loss of only 1-3 kg.…”

“…The majority of studies that we reviewed used exercise prescriptions of ∼60-180 min per week. [2][3][4]6,[8][9][10][12][13][14][15] Importantly, only four of these exercise studies considered change in body weight or composition as a primary outcome of the study. 5,7,10,11 The other studies addressed the effect of exercise on lipids, cardiovascular disease risk factors, glucose and insulin levels, BMD or diabetes.…”

Bone Mineral Density in Female Professional Athletes Involved in Weight Bearing and Non-Weight Bearing Exercises

“…Such a difference can be explained by the fact that exercises producing ground reaction forces, such as running or walking, are more effective in increasing BMD values whereas exercises associated with joint reaction forces, such as resistance training, best improve lean body mass and strength in postmenopausal women [4,23,46]. In other words, the present study showed individuals involved in golf, which is a pure weight bearing exercise, to have the least BMD values at the studied sites.…”

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“…Nevertheless, establishing comparisons is complicated, owing to the fact that bone loss rhythm is not the same in every anatomic zone (Mitchell & Yerges-Armstrong, 2011). In that sense, although prescription of physical exercise in order to increase bone density is not clear in older population, several papers prove the benefits of training (Ilona, Taina, Mirela, Eugenia, & Mihaela, 2010;Villareal et al, 2011;Kohrt et al, 1997;Iwamoto et al, 2001;Verschueren et al, 2004), either increasing bone status or diminishing the rhythm of loss.…”