I believe the fast twitch muscles are involved in getting good height on BT (and other skills)? Clearly some people are more naturally talented in this department, but can anyone train these muscles and become just as good? I don't believe Puma nor I (both quasi-athletes lol) have naturally good fast twitch muscle. Puma Jr. has been able to "do" a BT for over 2 years now, and it is getting better, but some of her teammates (especially the higher levels) seem to just float...I feel like they look on floor how she looks on tumble track. I cannot fathom this kid ever doing a double back! I'm not worried about it, just curious (yes I trust in the coaches, I promise! Lol)