Set-up: Set up on the floor resting on your hands and knees.
Lift: Raise your hips and knees off the floor so that your feet, hips and shoulders form a straight line. Brace through the core and maintain proper posture throughout. Hold for the prescribed amount of time.
Emphasis: Keep the shoulder blades back and together and do not allow the hips to sag.
Instructions and effects for the Plank with Straight Arms exercise 
