I know that I faltered on the twisting squats a little bit. I realized that rubber soles on rubber matting don't allow for the smoothest twist. Normally I perform these barefoot or in shoes on a polished dancefloor. I've also seen people perform the 'Cossack squat' with their extended leg on the ground. In the video, the gymnast doesn't and the movement tips don't mention it being necessary for mastery. Thoughts?