The effect of resistance training on bone mineral density in postmenopausal women

Osteoporosis is a systemic disease of the skeletal system characterized by low bone mineral density (BMD) and microarchitectural deterioration of bone tissue, which leads to a decrease in bone strength, greater bone fragility, and consequently to an increased risk of fractures. Osteoporosis is three times more common in women than in men, partly because women have a lower maximum bone mass, and partly because of the hormonal changes that occur at menopause. Regular exercise, and especially weight-bearing exercise which has various positive osteogenic effects, is an effective, safe and inexpensive method for preventing or delaying osteoporosis. The problem of this research is the review, systematization, analysis and comparison of the results of scientific research papers that examined the effects of resistance training on BMD in postmenopausal women. Five electronic data bases (Google Scholar, PubMed, MEDLINE, ERIC, and Research Gate) were searched, and search terms included ‘menopause’, ‘postmenopausal women’, ‘osteoporosis’, ‘bone mineral density’, ‘bone mass’, ‘resistance training’, ‘strength training’ and ‘weight-bearing training’. Inclusion criteria were controlled trials, postmenopausal women, with or without calcium supplementation. A systematic review of the available literature was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. To determine the quality of each study, the Physiotherapy Evidence Database Scale (PEDro) scale was used. A total of 16 studies met the inclusion criteria and total sample consisted of 1228 postmenopausal women. The review showed that this type of research was mostly done on a sample of less than 50 respondents; the shortest study lasted 24 weeks and contributed to the preservation of bone mineral density, and the longest had lasted for three years, during which the density improved. Calcium supplementation (600 up to 1500 mg per day) found its place in the protocol of seven studies, which gave good results in combination with exercise. Most of the studies have found a positive effect of resistance training on BMD of postmenopausal women (on the density of the lumbar spine, hips, forearms, and the whole body), but when it comes to strength training it had a positive effect only when it comes to BMD of the lumbar spine and hip, and on the total body when combined with hormone therapy. From the results of these studies we can clearly conclude that resistance training is good not only for the preservation of BMD, but that this type of training during the period longer than six months, leads to an increase in both total and regional BMD in postmenopausal women.
Keywords: menopause, osteoporosis, bone density, strength training