Come into an all fours position on an exercise mat with your hands directly under your shoulders and your knees directly under your hips. Lift your knees so they hover a few inches off the floor. This is your start position. Keeping your core braced and a neutral spine, gently lift your right foot a few inches off the floor. As you do this, simultaneously lift your left hand a few inches off the floor. Hold this top position for a count of one before returning both your foot and hand to the start position. Repeat the same sequence using the opposite foot and hand. Keep alternating sides for the required number of reps (or time).