Hand-held dynamometry fixated with a tripod is reliable for assessment of back extensor strength in women with osteoporosis

Summary An appropriate method to assess back extensor strength in clinical practice has not yet been described. Our results showed that a hand-held dynamometry fixated with a tripod is reliable for assessing back extensor strength in women with osteoporosis. Introduction Back strengthening exercises play an important role in the rehabilitation of patients with osteoporotic vertebral fractures. Evaluation of the effect of back strengthening exercises requires a method suitable for use in clinical practice to measure back extensor strength. A hand-held dynamometer (HHD) is quick and easy to handle in clinical practice. Currently, there is a lack of evidence whether a HHD is reliable for assessment of back extensor strength in people with osteoporosis. When using a HHD, it may be difficult for the tester to provide a counter pressure corresponding to the effort of the patient. In order to accommodate this, we have developed a tripod and a belt system, which was used to fixate the HHD. This study examined the intra-tester reliability of back extensor strength assessment in women with osteoporosis using a HHD. Methods Back extensor strength of the participants was measured on two events with 7-day intervals. Test procedures were standardized, and all tests were performed by the same tester. Results Forty-eight women with osteoporosis and vertebral fractures were included in the analysis. The coefficient of variation was 22 % using a HHD fixated by the tester and 17 % using a HHD fixated with the tripod. ICC was 0.75 (95 % confidence interval (CI), 0.63 and 0.88) when using a HHD with fixated by the tester and 0.90 (95 % CI, 0.84 and 0.95) when using a HHD fixated with the tripod. Conclusion A HHD fixated with a tripod is reliable for the assessment of back extensor strength in women with osteoporosis and vertebral fractures.