Lie on your back with your knees bent and your feet flat on the floor.
Tie an exercise band around both knees and place a plastic cup upside down on the knee of your weakest leg.
Tighten your core stability muscles before slowly dropping your stronger leg out to the side, pulling against the band.
The weaker leg should remain still, making sure the cup does not fall as your strong leg moves.
Keep your core muscles working whilst you bring your knee back up to the starting position.
Do not allow your pelvis to rotate during this movement.
