MUSCLES ENGAGED Chest Strengthening the chest muscles will help you push things easily and effortlessly. The muscles in your chest help stabilize your shoulder joint, which reduces your vulnerability shoulder joint injuries. Working your chest muscles also has an aesthetic factor (body contouring). Triceps Triceps are an often forgotten muscle group. Triceps are located on the opposite side of the biceps at the back of the upper arm. Well strengthened and defined triceps make the arm look bigger and sleeker (reducing the "flabby arm" look). Exercise Instructions Step 1 Start in a modified push-up position with your hands under your shoulders, your knees bent and feet crossed. Step 2 Keep your abs and butt tight as you lower your body to the ground. Step 3 Press your body back up to the starting position while maintaining a rigid plank position.