What would be a good shoe or shoe type to do some track workouts in for someone who is a slightly above average local runner -- if there is such a thing. I was looking into buying a cheap pair of XC flats or something to that effect to do my track workouts in. I am a bigger guy, 6-7 195, but have never had foot/leg problems. Whatever I get, I plan on only using on the track. I'm not brave enough to use em on the road.