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Bone mineral density
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- Creator:
- Lee, L.C., Shdo, S.M., Jaque, Sarah, Pierce, R.A., and Ahles, C.P.
- Description:
- The purpose of this study was to determine if an exercise threshold existed in stimulating an elevation in bone mineral density (BMD), via resistance training, during the growth period in male rats. 27 male rats were randomly divided into Control (Con, n = 9), 3 ladder climb resistance trained group (3LC, n = 9), and 6 ladder climb resistance trained group (6LC, n = 9). The 3LC and 6LC groups were conditioned to climb a vertical ladder with weights appended to their tail 3 days/wk for a total of 6 wks, but the 6LC group performed significantly more work than the 3LC group. After 6 weeks, left tibial BMD (mean±SD) was significantly greater for 3LC (0.225 ± 0.006 g/cm2) and 6LC (0.234±0.008 g/cm2) when compared to Con (0.202±0.013g/cm2). Further, bone strength (force to failure in Newtons) was significantly greater for 3LC (132.7±13.7) and 6LC (130.0±22.8) compared to Con (102.0±10.1). There was no significant difference in BMD or bone strength between 3LC and 6LC. The results indicate that both resistance training programs were equally effective in elevating BMD and bone strength in growing rats. These data suggest that during growth, there is a stimulation threshold where more work per exercise session is ineffective in promoting additional bone formation.
- Resource Type:
- Article
- Campus Tesim:
- Northridge
- Creator:
- Jensen, Brent
- Description:
- Background: Osteoporosis has its highest incidence among postmenopausal women.1 Bone Mineral Density (BMD) correlates with risk of fracture in that, for every standard deviation decrease in BMD, the relative risk of fracture approximately doubles depending on the skeletal site and type of fracture.2 Bone behavior and adaptation are currently predicted by Wolff?s law that states bone will change in response to new forces on it.3 Whether exercise can increase BMD remains ambiguous. The purpose of this meta-analysis and systematic review was to examine the effect of high-intensity-resistance training as compared to low-intensity exercise on BMD in postmenopausal women at the femoral neck and lumbar spine. The hypothesis is that high-intensity-resistance training will be more effective in increasing BMD compared with low-intensity exercise. Methods: Studies eligible for inclusion were peer-reviewed randomized control trials (RCT?s). Postmenopausal women with a BMD T-score from 0 to -2.5 were included in this evidence based review. Areas of interest for this study include the lumbar spine and femoral neck. Individuals with osteoporosis were excluded. Computerized searches of scientific databases were undertaken. The effect size, standard error of effect size, lower-confidence interval, and upper-confidence interval were calculated for individual studies and then pooled. The Q-statistic and p-value were calculated to determine heterogeneity or homogeneity. Results: The original search strategy recognized 12017 studies, of which 50 needed further full-text screening, and the full-texts of 4 articles met the inclusion criteria and were critically analyzed. BMD changes at the lumbar spine demonstrate heterogeneity between studies and BMD changes at the femoral neck demonstrates homogeneity between studies. Statistical analysis of the results found no significant differences in BMD at the lumbar spine or femoral neck when comparing high-intensity resistance training to low-intensity exercise with a small effect size at both the lumbar spine and femoral neck. Conclusion: It is important to advocate and prescribe postmenopausal women with an exercise program achieving adequate skeletal loading through strength training and weight bearing exercises in order to maintain or improve BMD.
- Resource Type:
- Dissertation
- Identifier:
- .b65426642
- Campus Tesim:
- Fresno
- Department:
- Physical Therapy
- Creator:
- Peters, Mallory
- Description:
- Understanding how culture shapes skeletal development, maintenance, and decomposition is critical to bioarchaeological studies that depend on skeletal assemblages to make conclusions about past populations. Few studies have thus far focused on how socioeconomic status has impacted bone mineral density and skeletal preservation. To address this, the current study compares bone mineral density in different skeletal collections and taphonomic damage within a single historic Californian skeletal collection. It was hypothesized that (1) cultural factors would impact bone mineral density, (2) that the Santa Clara Valley Medical Center (SCVMC) population’s mean bone mineral density is impacted because of its marginalized status, (3) within the SCVMC sample the hospital patients will have lower density than non-patients, and (4) individuals within the SCVMC sample with lower density will have higher rates of taphonomic damage. These hypotheses were tested using second metacarpal radiogrammetry to assess bone mineral density levels in four samples and compare these values across populations. The results indicate that the populations examined in this study do not have significantly different bone mineral density levels but the SCVMC collection’s density is lower than the modern and contemporaneous historic populations examined. Additionally, within the SCVMC collection there was no significant difference in density levels between patients and non-patients. The one hypothesis that was supported was that individuals in the SCVMC collection with lower density levels incurred greater amounts of taphonomic damage than those with higher density levels. This line of study would benefit from using larger and more diverse samples with greater demographic information. It supports previous literature which identifies bone mineral density as a key component in susceptibility to taphonomic processes but does not suggest that culture is a predominantly driving force in determining density levels for populations.
- Campus Tesim:
- Chico
- Department:
- Anthropology