Starting Position: Lie flat on your back on the floor / mat with your knees bent and feet flat on the floor. Your arms are by your sides. Brace your abdominal muscles to stabilize your spine. Pull your shoulder blades down your back. Try to keep these engagements throughout the exercise. Slowly lift both feet off the floor. Straighten your knees until your thighs are vertical to the floor. Your toes can point away from your body. (DO NOT move your thighs beyond this point as that shifts your body weight from your butt into your low back, causing increased stress to the low back). Put your hands on your thighs. Shoulder blades are flat on the floor.
Gently exhale. Use your abdominals to bring your head and shoulders of the floor, curling the spine. Reach your hands along your thighs toward your ankles. Keep your head aligned with your upper spine. Do not lower your chin, jut it out or drop your head back.
Continue curling upward until the tips of your shoulder blades lift completely off the floor. Hold this position for 5 - 10 seconds. Slowly return to your starting position and repeat the movement. Complete a set of quality repetitions. Discontinue the exercise when you are unable to maintain good form.
To maximize the benefits of this exercise and reduce the potential for injury, it is important to control your movement speed, keep your thighs aligned vertically and roll your trunk upwards and downwards during the exercise.