<qa>  What is the main cause of SCI?Spinal cord injury SCI prevents normal leg exercise which leads to secondary complications, including cardiopulmonary deconditioning, a high incidence of pressure sores, and bone demineralisation. Wheelchair sports do not raise fitness to the level of sedentary non-injured people but it has been shown that cycling via functional electrical stimulation, FES-cycling, can. Previous studies have been clinic-based; this limits the exercise time and is inappropriate for widespread use. We propose to show that home-based FES-tricycling can be a recreation, and can also lead to significant health benefits. 