Shortly after I got home from rehab, I got my own FES (Functional Electrical Stimulation) bike so I could do my own therapy at home. The FES bike, made by Restorative Therapies, is essentially a stationary bicycle that uses electricity to stimulate the muscles in my legs directly to work the pedals on the bike. The benefits from using active therapy, rather than something that only moves my legs passively, is that the muscles are actually doing the work. This is better exercise, increases circulation, and reduces atrophy and spasms.
I have been trying to use the bicycle three times a week, and definitely notice a difference when I miss a few days; when that happens my legs can get quite stiff, with more spasms. Recently I passed 500 sessions total since I got the bike. RTI stores data from each session on its server so I can track progress, the graph here shows total energy expended during each session from the very beginning. You can see that a while ago there was an increase when I upped the time of each session a bit, from 40 to 45 minutes. And, more recently, the bigger jump shows where I increased the resistance that the bike provides, making the muscles work harder. This change has had an interesting effect: When I do have a spasm now, it seems that my legs are a bit stronger and I have to be careful not to accidentally kick something.
I have never really noticed the exercise aspect of riding the RTI bike, and my pulse doesn't increase much when I'm on it, but over time I will continue to ramp up the resistance to see what happens.