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Back-flying forward and backward movement is one of the primary skills that you will need to learn in order to control yourself on your back.
The primary objective is to be able to safely and successfully begin in a neutral back-flying position, fly forward toward the wall, stop and then fly backward, under control the whole time. Ideally, begin learning this skill while still on the net, then eventually get to a point where the Instructor can increase the wind speed to become proficient at flying forward and backward off the net.
As you become more comfortable with this move, you can increase the speed of the wind, which can provide more power. You can also adjust your position slightly, by fully extending your arms above your head and rolling your head and shoulders back, which will provide a slight arched shape at your upper body. This along with keeping your heels tucked toward your bottom will allow for a steeper body pitch, ultimately giving you more power. Remember, the faster you are traveling, the more aggressive your stopping input will need to be to avoid contacting the wall.
Visit the IBA Skills page to download the full lesson plan and to find post-flight evaluation questions and suggestions.
Back flying, neutral position: HERE
Back flying, turns: HERE
Dynamic Progression series HERE