Cross training is key to give your body a little rest from running. On days that I'm fatigued and my legs just can't get back under me and recover, I like to hop in the pool. After a long run, I'll go in a pool, which seems to stretch my spine and hips. I don't swim hard, but it loosens up my legs. Also, yoga is great for cross training and recovery. Runners get tight hips and yoga is perfect to loosen them up, relax, and stretch out. — Shalane Flanagan