The pushup is a stability movement using shoulders, arms, triceps and biceps. The proper position for a pushup is to start with the feet shoulder-width apart with hands directly beneath the shoulders and elbows moving backward not outward. As the body is lowered, tighten the core of the body and lower the chest to the floor breaking the 90-degree angle in the elbows. While in the down position, keep the body tight and avoid arching the back. Push up to the starting position.