The side lying leg raise builds strength in the outer portion of the glutes and helps to prevent injuries associated with weak hips. This exercise also increases core strength.
Lie on one side with your lower arm on the floor and upper hand in front of your body for support.
Bracing your abs, bring your bottom leg slightly in front of your top leg, letting the inside of your top foot rest on the ground. Then lift the upper leg up to the ceiling, keeping your hips stacked. Pause and then lower the leg.
All of the movement should happen at the hip. Avoid moving at the upper body.
Keep the knee straight throughout the entire exercise.
Perform the movement in a slow and controlled fashion. Avoid using momentum to get your leg up.