Does 12 weeks of regular standing prevent loss of ankle mobility and bone mineral density in people with recent spinal cord injuries?

The purpose of this study was to determine the effects of a 12-week standing program on ankle mobility and femur bone mineral density in patients with lower limb paralysis following recent spinal cord injury. An assessor-blinded within-subject randomised controlled trial was undertaken. Twenty patients with lower limb paralysis following a recent spinal cord injury were recruited. Subjects stood weight-bearing through one leg on a tilt-table for 30 minutes, three times each week for 12 weeks. By standing on one leg a large dorsiflexion stretch was applied to the ankle and an axial load was applied to the bones of the weight-bearing leg. Ankle mobility and femur bone mineral density of both legs were measured at the beginning and end of the study. Ankle mobility (range of motion) was measured with the application of a 17 Nm dorsiflexion torque. Femur bone mineral density was measured using dual energy X-ray absorptiometry (DEXA). The effect of standing was estimated from the difference between legs in mean change of ankle mobility and femur bone mineral density. The results indicated a mean treatment effect on ankle mobility of 4 degrees (95% CI 2 to 6 degrees) and on femur bone mineral density of 0.005 g/cm² (95% CI -0.015 to 0.025 g/cm²). Tilt-table standing for 30 minutes, three times per week for 12 weeks has a small effect on ankle mobility, and little or no effect on femur bone mineral density. It is unclear whether clinicians and patients would consider such effects to be clinically worthwhile.