How does one cross train for a half marathon?

I saw a training schedule for a half marathon and the schedule devoted one day towards cross training. What are some good cross training exercises to help with running?|||when they say cross train they are also giving you the choice of rest. so basically do something that will not put much strain on the body. do not listen to the person who said sprints because sprint work outs should already be in the schedule as interval work. so things to do is go on relaxing bike ride maybe rowing but that might make you bit tired. the main thing to do in those workout schedules is to do the work and rest when it says rest. rest can sometimes be the best thing for a runner. good luck.|||sprints, eliptical, skiing, hiking, spinning, bike rides, weight lifting, yoga. . .your choice!