Why does it keeps on folding up, almost hitting my butt whenever I do a stroke? Any strokes, forehand, 1hbh or 2hbh. I mean, it totally folds up. If im wearing heels while playing, the heels would struck my butt. I haven't seen anybody in person that have this yet. No one from the pros either. Their legs almost doesn't leave the ground when they do a stroke. Does anybody have this while playing?