To perform this exercise, lie flat on the floor, with the heel of the leg to be exercised on a bench or chair and your arms by your side. Lift the opposite side so that the heel is off the bench, with the knee directly above the hip.
Lift your bottom up from the floor by pushing through the weight bearing heel. Imagine a line between your hips, which you try to keep level as you lift your bottom from the floor. Only lift your bottom up as far as feels comfortable, as to avoid causing strain on your hips or lower back.