EXECUTION
- Straddle an exercise bench and assume a stable seated position with your legs bent and feet on the floor.
- Hold a dumbbell in each hand on bent arms so that the dumbbells are approximately neck high. Your elbows should be alongside the body or slightly in front,
- Use a neutral grip so that the palms face one another.
- Inhale slightly more than usual and hold your breath as you begin to press the dumbbells upward. Keep your vision focused forward.
- As the dumbbells pass the top of your head, rotate the arms inward so that you end up with a pronated grip, i.e., with the palms facing away, when the arms are fully extended overhead.
- When you begin, the elbows should point forward and when the dumbbells are fully raised, the elbows should point outward.
- Lock the arms in the top position but do not hyperextend the elbow. Pause momentarily and then exhale and return to the initial position under control. (Laterally rotate the arms as you lower the dumbbells to bring them back into the in-front-of-the-body position with the palms facing one another.
- Repeat when you are ready and be sure to raise the dumbbells as high as possible on the up phase.
TRAINING TIPS
- When first learning the feel and rhythm of this exercise, it is important that you use relatively light weights. With heavy weights you will have to make adaptations which could change the way the exercise is done. Doing this can lead to injury.
- In general, you should execute only one joint movement in an exercise for maximum safety and muscle development. In this exercise, because of the medial rotation in the shoulder joint, you go from flexion in the shoulder joint to abduction in the shoulder joint. Because of this, it is important that you get through the toughest point of the shoulder flexion movement before rotating into abduction. If not, you may be setting yourself up for injury.
- Breathing is important in execution of this exercise, especially when you use heavy weights. The breathing, especially the breath holding on the exertion phase, helps to stabilize the trunk which in turn allows for safe and effective movements in the shoulder joints and shoulder girdles.
- Do not lean back in the initial stages of pressing the dumbbells upward. Maintain an erect trunk position throughout execution and keep your vision focused forward.
- Avoid jerking the dumbbells upward and then rotating the arms or letting them down quickly with a twist or sudden stop in the bottom position. Any forceful movements of this nature can overstress the shoulder and compact the spine, both of which can cause injury.
- Be sure to raise the dumbbells as high as possible so that you have maximum contraction not only of the deltoid but also of the upper trapezius and triceps muscles.
- Do not contract the abdominals to stabilize the trunk. Stabilization comes from the breath holding and contraction of the erector spinae muscle which also maintains the normal curvature of the spine.
MAJOR MUSCLES INVOLVED In the shoulder joint the major muscles are the anterior and middle deltoid, upper pectoralis major and supraspinatus. The deltoid is a three-headed muscle that covers the front, side and back of the shoulder. It extends from the scapula to the middle of the upper arm. The pectoralis major is a large muscle that covers almost the entire chest. From its attachment on the arm just above the deltoid attachment, it spreads out to the clavicle on top, sternum in the middle, and the cartilages of the first six ribs on the bottom. The coracobrachialis is a small muscle located deep beneath the deltoid and the pectoralis major on the front and inner side of the arm. The supraspinatus is a small but powerful muscle that lies under the upper middle part of the trapezius. In the shoulder girdle, the major muscles involved for moving the scapula to allow for the shoulder joint actions are the serratus anterior and the upper and lower portions of the trapezius. The serratus anterior lies on the outer surface of the ribs at the sides and is covered by the scapula at the rear and the pectoralis major in front. It is often mistaken for the external obliques. The trapezius is a large flat sheet of muscle located on the upper middle portion of the back. It runs from the base of the skull to the posterior border of the clavicle and through to the last thoracic vertebrae. In the elbow joint, there is only one major muscle involved, the triceps brachii, a large muscle that covers the entire backside of the upper arm. It is divided into 3 sections (lateral, medial and long heads) which run into a common tendon to insert on the ulna bone in the forearm.
MUSCLE/JOINT ACTIONS At the beginning of the Arnold press, there is flexion in the shoulder joint in which the upper arms travel upward in an anterior-posterior (back to front) plane from a position alongside the body. The anterior deltoid is most important at this time. As the arms are medially rotated, the elbows move out to the sides and there is shoulder joint abduction. In this action, the arms move from out-to-the-sides to an overhead position. The middle deltoid is most important at this time. The upper pectoral involvement is basically the same throughout the upward press phase. The coracobrachialis assists in shoulder joint flexion and outward rotation of the arm while the supraspinatus is powerful in shoulder abduction. The latissimus dorsi, teres major and subscapularis are activated in medial shoulder rotation but not very strongly. In the shoulder girdle, the muscles are responsible mainly for upward rotation and elevation of the scapula. In upward rotation, the right scapula turns counterclockwise and the left clockwise when viewed from the rear. In addition, the scapula are elevated (moved directly upward). The upper trapezius is most important in both of these actions. The serratus interior is another major muscle for upward rotation of the scapula together with the upper and lower portions of the trapezius. In the elbow joint, the triceps is involved in extension in which the forearms move away from the upper arms until the arms are fully straightened above the head.
SPORTS USES The Arnold press is a good exercise for development of the front and sides of the shoulder as it strongly involves the anterior and then the middle deltoid through an appreciable range of motion. It is also a great exercise for development of the upper and lower portions of the middle of the back (trapezius) and the triceps. Raising the arms overhead is important in a multitude of sports. This includes sports such as weightlifting (clean and jerk, snatch), tennis (serve and smash), basketball and volleyball (blocking, passing), and gymnastics (high bar, parallel and uneven bars, vaulting, handstand press), tumbling (pushing off the floor) hand balancing, pushing and holding a top performer, and in the recovery strokes in swimming.