What should I do to improve my tumbling? To make high school cheerleading?
The only person who can tell you what the high school tryout requirements are is the coach for that team. So you need to go ask about that. If tumbling is required, then get into a class right away. You can do tumbling drills, jumps, and stretching at home to help you improve. Do NOT jump with weights on because you can really hurt yourself that way. Just keep jumping and do some ab work like crunches to give you the muscle strength you need to roll your hips under. Good luck!