Just like when you start the backhandspring you NEED a spotter for this at first.
When you start out the easiest way I have found to do it is to start standing straight up with your hands held out in front of you. Make sure your spotter has a hold of you tightly.
Step2
When your ready jump straight up and bring your arms up to your ears. Don't tuck (pulling your legs in) until you are at the highest point. Once you tuck and your upside down grab your knees, thighs, ankles, which ever you feel more comfortable with.
Step3
By this time you should be rotating pretty fast, and should be getting ready to land. Don't uncurl until the last bit of the trick. You don't want to fall backwards once you land. If you uncurl to late you'll fall as well. Now that you've landed you have done it!
Get comfortable with the spotter and eventually move to the wedge. Just like the backhandspring get spotted a few times, and then work your way down it.
Tips & Warnings
If your having problems with throwing your head back when you job try getting a little soft ball and sticking it under your chin. When you go to do the trick again make sure to keep the ball there, and it will train you not to throw your head.
DO NOT jump straight back! This is not a backhandspring.
If you have never done gymnastics do not try this!! You will get hurt.
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