Bring yourself to the ground and enter a high plank position with your hands directly under your shoulders and your feet elevated on a chair (or equivalent raised surface). This is your start position. Keeping you core braced, lower your chest towards the ground by bending your elbows until your chest is just above the ground. Inhale as you do so. You should maintain an unbroken line from your head to yours toes throughout this lowering phase. Pause at the bottom of the movement, then press upwards from your chest and shoulders, straightening your arms as you return to the high plank position. Exhale as you do so. Repeat for the required number of reps (or time).