Back Tuck Help!

If you could post a video on youtube and then include the link, I will help in any way I can.

When I teach standing tumbling I use an approach of "Swing, sit, jump" with most of the concentration on the swing.

Frist start with your arms in a low V, swing arms back, as they swing back you should feel your chest wanting to roll over your toes. That's perfectly fine! Then as your arms reach back and up, then swing them forward while starting your sit. Once your arms are by your knees with shoulders over your toes so that the weight of your body is athletic then lift your ARMS not your chest! If you lift your chest then your arms will be playing catch up the entire time, sounds like that you are doing now. Then your arms lift squeeze them by your head. This will bring your chest it!

Another tip when doing your tucks, do not bring your knees into your chest. All that is doing is making your chest drop!