Standing strengthening hip flexion and extension DR (level 2) (Hip flexion/extension drag resisted, swinging leg (level 2), standing, fin on foot)

Stand up straight with a wall to your side.
Hold onto the wall with your nearest hand, you will be exercising your opposite leg.
Stand on a pool step with your foot nearest the wall and place a fin on your other foot.
Keeping your knee straight, quickly swing your leg forwards and backwards.
Swing your leg quicker to increase the difficulty of this exercise.