Effect of detraining on bone strength in subjects with chronic spinal cord injury after a period of electrically-stimulated-cycling: a small cohort study

To investigate adaptive changes in bone and muscle parameters in the paralysed limbs after detraining or reduced functional electrical stimulation (FES) induced cycling following high-volume FES-cycling in chronic spinal cord injury.
Five subjects with motor-sensory complete spinal cord injury (age 38.6 years, lesion duration 11.4 years) were included. Four subjects stopped FES-cycling completely
after the training phase whereas one continued reduced FES-cycling (2–3 times/week, for 30 min).
Bone and muscle parameters were assessed in the legs using peripheral quantitative computed tomography at 6 and 12 months after cessation of high-volume FES-cycling.
Gains achieved in the distal femur by high-volume FES-cycling were partly maintained at one year of detraining: 73.0% in trabecular bone mineral density, 63.8% in total bone mineral density, 59.4% in bone mineral content and 22.1% in muscle cross-sectional area in the thigh. The subject who continued reduced FES-cycling maintained 96.2% and 95.0% of the previous gain in total and trabecular bone mineral density, and 98.5% in muscle cross-sectional area.
Bone and muscle benefits achieved by one year of high-volume FES-cycling are partly preserved after 12 months of detraining, whereas reduced cycling maintains bone and muscle mass gained. This suggests that high-¬volume FES-cycling has clinical relevance for at least one year after detraining.