My mare doesn't like the round pen. It doesn't matter if I'm lunging or riding her in there, she acts weird and nervous and speeds up. The pen is in the middle of a large paddock. Is she afraid of closed in spaces? She's an ex-racer if that's any help. But I have also lunged her in the small barnyard and it hasn't been a problem. She's much better when I ride or lunge in the arena.