As a child with a disability following Polio in 1948 I wore a full length calliper on my left leg. Because I found walking difficult, as soon as I could I would use a bicycle as my main means of getting about. I could only push with my right leg, my left leg was just an appendage. ( and still is) This worked well until I was 16 and bought a motorcycle, one with hand gear changes, a Velocette.
When I drove cars at age 17 or thereabouts I got rid of all my bike (1) tandems (2) motorcycle (1) and continued on 4 wheels till about 25 years ago when camping in France my eldest daughter suggested we borrowed a tandem from the people in the next door tent so she could try riding one herself. It was not a success. In the mishap which soon followed, I broke the femur of my left leg and spent about 6 months off work learning to walk again.
By then I had internal scaffolding as well as external scaffolding and had a reduced ability to bend this leg. When, on the odd occasion I tried to ride a bike I would be lifted out of the saddle because of all this hardware, which was amusing to onlookers but not too clever for me.
As time went by, as exercising for me was difficult, I steadily put on weight. Now, aged 71 I’m about 6 stone overweight and although I joined a gym found the changing facilities a trial and was restricted on the equipment I could use. I thought about riding bikes again but could not work out how to cater for my reduced flexion. All sorts of ideas occurred but these would need clever, and no doubt expensive, engineering to fulfil.
I stumbled across a Charity which helped people with a disability to ride once more. They put me in touch with an engineering company who produced a “swing shank” which, the fitted correctly would enable my left leg to describe a circle of a smaller diameter than my right leg which would be doing all the work.