Passing through? Take a second, stop, and – boom – you worked your core!

Stand in a door frame. Check your posture: Is your body square to the frame? Are your shoulders and head back, your hips and shoulders level?

Without shifting weight, lift your left knee. Alternate pressing sideways into each side of the frame with one hand. Use your core to resist the pressure of your hand and keep perfect alignment – your foot, knee and hips do not move. Do five repetitions, then switch and repeat on the opposite leg.Carrie Cockburn/The Globe and Mail

Originally published at The Globe & Mail .