Hello Chris welcome to BF. I have a similar situation with nerve damage right side partial foot paralysis and muscle weakness due to broken back / fusion surgery three months back. But I am over twice your age! Physical therapy three days a week has helped some. Forbidden from riding a bike but can pedal for hours on a recumbent indoor machine. Hope to be riding outdoors next spring. I assume you have already seen the thread fifteen lines down on this sub forum almost of the same name as yours "Limited leg ROM looking for options" by started by yss - sorry I don't know how to link to it - it has about all you need to know about cranks, ROM issues etc. Just keep your therapist in the loop because He/She is key to muscle growth and flexibility improvement. Good luck!