Stand up straight on a ramp, facing down the slope.
Position your feet hip-distance apart.
Move your weight onto the leg you would like to exercise, lifting the other foot off the ramp.
Keeping your gaze directly ahead and your back straight, push your hips back a little as you bend your knee, lowering down into a squat.
Ensure your knee travels directly forward over your toes and does not drop inwards.
Once you reach the bottom of the squat, bring your elevated leg back onto the ramp, and push though both feet as you stand back up and return to the starting position.
Repeat.