I served back before missionaries could exercise. Riding a bike, walking, and once a week p-day basketball kept me in shape compared to a regular person, but I was far from good basketball shape. I didn't have that spring or lateral quickness. Though I could dunk again within a few months, it took maybe 9 months before I could jump as high as I could before.
I think being able to exercise more frequently like they can now could make a big difference in reducing recovery time.