SYSTEMATIC STRENGTH TRAINING AS A MODEL OF THERAPEUTIC INTERVENTION -A CONTROLLED TRIAL IN POSTMENOPAUSAL WOMEN WITH OSTEOPENIA

Physical exercise is often recommended as a therapeutic tool to combat pre- and postmenopausal loss of bone density. However, the relationsh ip between training dosage (intensity, duration, frequency) and the ef fect on bone density still is undergoing discussion. Furthermore, the exercise quantification programs are often described so inadequately t hat they are neither quantitatively nor qualitatively reproducible. Th e aim of this investigation was to determine whether a clearly defined training of muscle strength, under defined safety aspects, performed only twice weekly, can counteract bone density loss in women with post menopausal osteopenia. Data from 16 women in the training group (age, 63.6 +/- 6.2 yr) and 15 women in the control group (age, 67.4 +/- 9.7 yr), of comparable height and weight, were evaluated. Strength trainin g was performed for 6 mo as continually adapted strength training, pro viding an intensity of about 70% of each test person's one repetition maximum. Bone mineral density of lumbar vertebrae 2 to 4 and the femor al neck was measured by dual-energy x-ray absorptiometry. Maximum perf ormance in watts and parameters of hemodynamics were controlled with a bicycle ergometer test to maximal effort. In addition, metabolic data were assessed. In the lumbar spine and femoral neck, the training gro up showed no significant changes, whereas the control group demonstrat ed a significant loss of bone mineral density, especially in the femor al neck (P < 0.05). The strength increase was highly significant in al l exercised muscle groups, rising to about 70% above the pretraining s tatus (P < 0.001). Heart rate and blood pressure data indicated a slig ht economization, and metabolism was not significantly influenced. Bas ed on these findings, we conclude that continually adapted strength tr aining is an effective, safe, reproducible, and adaptable method of th erapeutic strength training, following only two exercise sessions per week.