<p>You might also consider swimming. When my d couldn’t run because of a knee inflammation, her physical therapist told her to swim laps to keep up her endurance and cardio. He said that professional swimmers had no problem when they needed to run, but that runners had problems switching to swimming because they didn’t have the endurance that swimmers need.</p>
<p>Of course you need to like swimming. 
My d complained the whole time - said if she wanted to swim she’d have applied to USNA.</p>