Back extensor training increases muscle strength in postmenopausal women with osteoporosis, kyphosis and vertebral fractures

Abstract

We determined the efficacy of a back muscle extensor strengthening program on the back muscle extensor strength, kyphosis, height and thoracic expansion in women with at least one vertebral fracture, kyphosis and osteoporosis. Thirty-six patients were included and randomized to a control or a training group. The training focused on back muscle extensor strengthening program for 1 h, twice a week for 4 months and was performed by a physiotherapist. The main outcome measure was the back muscle extensor strength. In an intention-to-treat analysis no significant effects on back muscle strength in the training group vs. controls could be seen (p = 0.74). In a per-protocol analysis (n = 28), the training group increased back muscle strength from 290 ± 87 to 331 ± 89 N while the control group showed no improvement. After adjusting for the strength at baseline, a significant effect of training could be demonstrated (p = 0.029). When comparing the heights between the groups a significant group × time interaction was observed (p = 0.012) where the training women increased their mean height with 0.3 cm (p = 0.101) and controls decreased 0.44 cm (p = 0.045). The training group improved their thoracic expansion compared with baseline (p = 0.03). No effect of training on kyphosis was seen. In conclusion, a 4-months back extensor training program can improve back strength and seems to maintain height and thoracic expansion.

Key words::

• Back extensor muscle training
• kyphosis
• postmenopausal osteoporosis
• vertebral fracture

Acknowledgements

The authors wish to thank Catharina Sjöberg, Department of endocrinology, metabolism and diabetes, Karolinska University Hospital, Stockholm, for excellent help with measurements of patients and Sanofi-aventis for the purchase of the dynamometer “Good Strength”.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.