Stand up straight with a box behind you and a line on the floor directly in front.
Stand on your leg to be exercised and place your other leg on a box behind you.
Position your stance foot to the inside of the line.
Squat down on your stance leg, ensuring your knee travels forwards over your toes.
Push through the ball of your foot to spring up into the air.
Control the movement as you land back on the floor on the other side of the line.
Repeat, jumping back to the first side of the line.
Keep an eye on the control of your knee on the landing.
