How? Hold a light barbell overhead at arm’s length, with your hands double shoulder-width apart. Squeeze your shoulder blades together and raise yourself on the balls of your feet, heels raised as far as possible. Step forwards with your left leg and lower your body so your left thigh is level with the floor, but do not drop to either heel. Now drive back up to the start and repeat ten times on each leg.

Why? By holding the barbell overhead rather than on your shoulders you change your centre of gravity, forcing your thighs to work harder to control the weight. By raising yourself on the balls of your feet you give your calves a great workout, and you hit an under-trained muscle
in your thigh (the vastus medialis). This helps to stabilise the knee and guard against injury.