On your marks: Todd Ellis of Georgetown, centre, and Romi Walsh of North York, right, leave the starting line in a race yesterday at Sports on Wheels '84. The competition, held at Variety Village in Scarborough, was sponsored by physical and occupational therapy students from the University of Toronto. Competing on a team from the Ontario Crippled Children's Centre, Todd, 10, pedalled his tricycle to victory in the 200- and 400-metre races.