Strength training and bone mineral density of active postmenopausal women

Rationale: Osteoporosis is a global problem that affects one in three women and one in 12 men. More deaths are caused each year by osteoporosis than are caused by breast cancer, uterine cancer and ovarian cancer combined. Due to recent claims that exercise can help prevent and even treat osteoporosis, numerous studies have recruited people to be involved in many different types of exercise. However, no study has looked at the effect of a 15 minute strength training programme on already active postmenopausal women. The main focus of this study is to assess the benefit of adding three sessions of 15 minutes strength training to an already active population with low bone mineral density. Methods: Initially 31 women were recruited for the study. However, due to numerous reasons 19 subjects completed the 12 week study. Bone mineral density was measured and the subjects were randomly assigned to either the control of exercise group. The exercise group completed 12 weeks of strength training (three sessions per week working at 80% of their 1 rep max) in addition to their normal activities. The control group continued their normal activities for the 12 week study. Exercise programmes were adapted every four weeks to ensure subjects were still working at the desired intensity. At the end of the study bone density was measured again and data assessed using SPSS for Windows, Release 13.0. Results: The age range for this study was 46 years of age to 70 years of age. For the purpose of this study Low bone density was categorised as having T-scores below -1. All subjects with a t-score above -1 were excluded at the initial testing stage. Overall, mean bone mineral density for the control group was 91.83% ±13.6 and for the exercise group was 85.19% ± 15.58. However, there was no significant difference between the two groups at the initial stage. Following the 12 weeks study the mean bone mineral density for the control group was 91.69% ± 11.176 and for the exercise group was 88.09% ± 19.62. There was found to be no significant change in bone mineral density for the control group at the end of the study. However, the exercise group were found to have significantly increased bone mineral density following 12 weeks of strength training (p = 0.002). In addition, the exercise group also showed significant strength increases following the study (p = 0.02). Conclusion: This study has important, and positive, findings not only for individuals wishing to improve their bone density and quality of life, but also for health care professionals trying to reduce the huge £1.8 billion annual cost of osteoporosis related injuries. Although the results of this study are encouraging, more research is needed in this area