Starting Position: Lie in a supine (on your back) position on a mat with your knees bent, feet flat on the floor and arms spread out to your sides with your palms facing down. Gently exhale, stiffen your torso by contracting your abdominal/core muscles ("bracing") and slowly lift your feet off the floor, raising your knees directly above your hips while maintaining a 90 degree bend in the knees. Hold this position and breathe normally. Use your arms as a balance support.
Upward Phase: Exhale, contract your abdominal, core and hip flexor muscles and slowly raise your hips off the mat, rolling your spine up as if trying to bring your knees towards your head (your hips and pelvis should move towards your rib cage). Avoid any change in the angle of your knees during the roll-up. Use your arms and hands to assist with maintaining your balance and continue to curl-up until your spine cannot roll any further. Hold this position briefly.
Downward Phase: Gently inhale and lower your spine back towards the mat in a controlled fashion, moving your upper thighs backwards until they are positioned directly over your hips. Continue rolling out until your spine and pelvis (hips) contact the mat and your knees are positioned directly over the your hips with a 90 degree bend with your lower leg.