Start in a push-up position with your hands under your shoulders and your body in a straight line. Shift your weight onto one arm and reach the other hand back under your body to tap the opposite thigh, then return it to the floor and tap with the other hand. The reach is longer than a shoulder tap and travels under you, so your core has to work overtime to keep your hips level while the support disappears.

Works: abs, obliques, shoulders, triceps

Breathing: Exhale as you reach and tap, inhale as the hand returns to the floor.

Common Mistakes: Rocking the hips sideways with every reach, piking the hips up to shorten the distance, and rushing the taps until the plank falls apart underneath them.

Make Easier: Widen your feet for a more stable base, or build up with Shoulder Taps until the shorter reach feels solid.

Make Harder: Bring your feet together and slow every tap down, or move on to Seagulls to hold the lost support out at full wingspan.