Learn dragonfly negatives -- the lowering phase -- to develop core strength and muscular coordination crucial to properly executing the dragonfly. Lie on your back on a workout bench with the top of your head at the end of the bench.
Bend your knees and put your feet flat on the bench. Reach back and grasp the edges of the bench just to the sides of your head. An alternate technique is to grasp the end edge of the bench. Keep your upper arms perpendicular to the floor throughout the exercise.
Tighten your stomach muscles, bend your hips and pull your knees in toward your chest. Simultaneously pull tight with your hands, and drive your hips and legs upward. Bend only at your upper abs and middle back as you straighten your hips and legs to bring your body as close to perpendicular to the floor as possible.
Bend your knees 90 degrees and keep your thighs aligned with your torso for the starting position. Without bending your hips, slowly lower your feet to the bench. Tuck your knees again, drive your hips and legs up to the starting position and repeat. Start with one to two sets of five reps. Work your way to three to five sets of 10 reps, which may take a few weeks, before moving to the next step.
Work toward straightening your legs. When you are at the bottom of the bent-knee negative, extend your legs without touching the bench and then lower them to the bench. Return to the bent-knee starting position and repeat. Strive to perform three to five sets of 10 reps. When you can hold your legs straight about 2 inches above the bench for two seconds, you are ready for the full dragonfly. This step may take a few weeks.
Full Execution with Variations
Lie on your back on a workout bench and assume the vertical starting position. While keeping straight from your shoulder blades to your feet, lower your body until it is parallel to the bench and about 2 inches above it. Only your upper back and head should be touching the bench. Pause for a count of two and without bending your hips or knees, pull your legs up to the starting position and repeat. Strive for three to five sets of 10 reps.
Make a slight change in technique to perform the straddle-leg dragonfly. First, assume the vertical starting position. Part your legs and lower your body until you are a few inches above the bench. Pause, bring your legs together and return to the starting position. The wider you spread your legs, the easier the exercise.
Add resistance for more challenge. Strap on a pair of ankle weights, start in the vertical position and perform the exercise.