Keep the horse at least 3 feet away from an arena or round pen fence.

Don't ever Ride or Longe directly next to the fence, because the horse will quickly learn to 'lean' on the fence, and will then have ample opportunity to run your leg or spur into the fence, or rear and leap over the fence. (And believe me, where there is 'opportunity', there is action!)

While many people feel safer riding directly next to a fence, it is actually a false sense of security and extremely dangerous.