Perform this exercise in a controlled manner. Do not swing or use momentum as this may injure your back.
Your erector spinae muscles will become synergists if you hyperextend your lower back.
Performing this exercise with straightened knees recruits both your glutes and hamstrings. To decrease activation of the hamstrings, bend your knees. This will increase activation of your glutes and force it to contribute more to the movement.
Place a towel under your hips if there is any pain or discomfort.