classic33
Leg End Member
They don't come cheap though!Many seem to think that SPD is the only thing that can hold the foot securely to the pedal but there are lots of different methods out there and if you are a midfooter SPD isn't the obvious choice.
The nice thing with the Terra Trike Strapped Heel Support Pedals is the fact that you can use the muscles in the leg full out, with the SPD that wasn't possible for some reason maybe the leg "cuts out" when the calf muscle is overstreched