Bring yourself to the ground and enter a high plank position with your hands directly under your shoulders. This is your start position. Keeping you core braced, reach your left arm back underneath you to touch your right foot. Feel the contraction of your core as you move. Reverse the movement to return to the start position. Then reach your right arm back underneath you to touch your left foot. Return to the high plank position; this counts as one rep. Repeat this alternating sequence for the required number of reps (or time).
All you need is a mat and a few minutes, which makes this an easy one to slot into a busy week. Our workout app guide covers how short sessions still add up.
