Set-up: Start by lying on your back with knees bent. Raise your off-leg up and straighten it in line with your other thigh.
Movement: Pressing through your heel and firing your glutes, lift your hips off the floor. Your weight should rest on your heel and your upper back - not your toes or your neck and cervical spine. Extend your hips until they form a straight line with your knees and shoulders. Make sure the end range of motion comes from the hips - squeezing the glutes together at the top of the movement - and not from lumbar hyperextension.
Repetitions: Perform all prescribed reps on one side, then on the other. This counts as one set.