This skill requires dramatic abdominal and hip flexor strength. Tight hamstrings and lower back will make this significantly more difficult.
Using the parallel handles jump to a support position. Work hard to retract your shoulders and press down hard into the handles to keep your upper back from rounding out. Once in a stable position lift your knees to your chest. If your shoulders collapse inward try lifting your legs only part way up or spend more time on the Dip Support.