GrantLewisIsDNTMSounds like you need a lens specific for shooting follow focus. You're gunna want a wide lens or a fisheye. Rokinon 8mm and Opteka 6.5mm are both great fisheyes, but I don't know to much about wide lenses. Just do some research and watch some videos, you'll figure it out.
I have the opteka 6.5 and mostly use it for follow can . It is easy to keep in focus but you have to get super scarily close with it if you want the footage to look very good. Unless you want some hair raising follow cams or footage where you feel to far away from the skier I would get somethong longer.