The pull-up and chin-up are often considered to be identical exercises with the pull-up usually considered as the more difficult. In both the pull-up and chin-up actions you raise the body vertically utilizing many of the same muscles. But, the sections of the major muscles involved as well as some of the secondary (assistive) muscles are quite different.
The pull-up appears to be the more popular bodybuilding exercise for development of the latissimus dorsi. Thus it will be discussed this month.
MAJOR MUSCLES INVOLVED:
In the shoulder joint the major muscles are the upper latissimus dorsi, lower pectoralis major and the teres major. These muscles are assisted by the corachobrachialis, subscapularis, short head of the biceps and long head of the triceps. The pectoralis major originates on the inner two-thirds of the anterior border of the clavicle, the whole length of the sternum and the cartilages of the first six ribs near their junction with the sternum. It inserts by a flat tendon about three-inches wide into the ridge that forms the outer border of the bicipital groove of the humerus, extending from just below the tuberosities nearly down to the insertion of the deltoid. The latissimus dorsi covers a very wide area of the lower half and the upper sides of the back. It originates on the spinous processes of the lower thoracic and all the lumbar vertebrae, the back of the sacrum, the crest of the ilium and the lower three ribs. It inserts on the bottom of the intertubercular groove of the humerus by a flat tendon attached parallel to the upper three-fourths of the insertion of the pectoralis major. The teres major is located on the upper sides of the back. It is a round muscle which originates on the dorsal surface of the scapula at the lower end of its lateral border. Insertion is on the ridge that forms the inner border of the bicipital groove of the humerus parallel to the middle half of the insertion of the pectoralis major. In the shoulder girdle the major muscles involved are the rhomboid and pectoralis minor. The rhomboid lies beneath the middle of the trapezius. It originates on the spinous processes of the vertebrae from the seventh cervical to the fifth thoracic vertebra, inclusive. Insertion is on the medial border of the scapula from the spine to the inferior angle. The pectoralis minor is a small muscle on the front of the upper chest and is covered by the pectoralis major. It originates on the outer surfaces of the third, fourth and fifth ribs a little sideward from their junction with the costal cartilages. Insertion is on the end of the coracoid of the scapula. MAJOR JOINT ACTIONS:
In the shoulder joint there is adduction in which the upper arms move in the side plane from an overhead position towards the sides of the body. This action is performed by the lower pectoralis major, upper latissimus dorsi and teres major. In the shoulder girdle there is downward rotation of the scapula performed by the rhomboid and pectoralis minor. In this action the right scapula rotates clockwise and the left scapula counterclockwise when viewed from the rear. The axis of rotation is through the middle of the scapula.
SPORTS USES:
The pull-up is very important in all climbing actions when grasping with a pronated (palms-away) grip or with a neutral (palms facing) grip and pulling with the elbows out to the sides. These actions are frequently used in rock and mountain climbing. Firemen and policemen need this exercise to help them climb fences, walls and ladders, as do military men when going over various obstacles. Gymnasts are benefited from doing pull-ups in all pulling up actions on the horizontal bar and rings when using the pronated grip and often on the parallel bars when the elbows are out to the side and using a neutral grip. The pull-up develops the muscles needed in all forms of swimming, especially in the breast stroke and butterfly. For bodybuilders it is a very important exercise for developing the upper back muscles.
EXECUTION:
Grasp a horizontal bar with a pronated grip (palms facing away from the body). The arms and upper body should be fully extended and the hand grips should be 8-9 inches outside the shoulders. Relax the shoulders to get a full stretch of the latissimus dorsi muscle.
When ready, inhale slightly more than usual and hold your breath as you begin the pull-up. Concentrate on keeping the elbows out to the side and pulling them down to raise the body. Keep pulling the body upward until the chin is even with or slightly above the bar. Exhale and lower the body under control to the initial position. Repeat for the desired number of repetitions.
COMMENTS: 1) To more effectively work the upper lats, which give you “wings” and widen the upper back, the grip should be wide or as wide as comfortably possible. The wider the grip the more you knock out use of the lower portion of the pectoralis major and the greater the emphasis falls on the upper latissimus dorsi and the teres major. The closer the grip the more the lower portions of both the pectoralis major and latissimus dorsi become involved. 2) In the pull-up it is important that you bring the chin to the bar or slightly over the bar while still keeping the elbows out to the sides. In this way you work the upper latissimus dorsi and the other muscles through the greatest range of motion. Note, however, that if the grip is extremely wide the amount of body raising is diminished proportionately. The closer the hand grip the further the trunk is from the bar and the greater the range of motion in the shoulder and elbow joints but the muscular involvement changes. 3) Doing the pull-up bringing the back of the neck to the bar is not recommended because it greatly decreases the range of motion of muscle involvement. As a result, you get less muscular development and you may open yourself up to injury. When you bring the head and chest forward and the elbows all the way to the rear in order to bring the back of the neck to the bar, the shoulder joints are placed in a vulnerable position. In essence, the scapulae get pulled in very close to the spine (adducted) instead of remaining in their normal, slightly forward angled position as occurs when the bar is kept in front of the body. When you pull up with the bar in front of the head, the arms remain in their natural plane of movement and thus the exercise is very safe. But, when you pull to the behind-the-head position, the shoulder joint angle changes and shoulder impingement may occur. Thus pulling up so the bar remains in front of the head is much safer and more productive. 4) When you do the wide-grip pull-down you also strongly involve the corachobrachialis and the subscapularis muscles. The subscapularis is a rotator cuff muscle which is strongly involved in medial rotation of the upper arm, as is the latissimus dorsi and teres major. Because of this, there is a tendency for upper arm forward rotation to occur as you do the exercise. To prevent this from happening, the lateral rotators, which involve the posterior deltoid and the teres minor and infraspinatus, undergo contraction to prevent the medial rotation and to help stabilize the shoulder joint. Additional stabilization as well as assistance in bringing the arms down sideways to the body comes from contraction of the short head of the biceps and the long head of the triceps. These muscular contractions also contribute to joint safety. 5) The rhomboid and the pectoralis minor muscles, also play very important roles. When you assume the initial fully extended arm and trunk position these muscles, especially the lower portions of the rhomboids, are strongly stretched because of the upward rotation of the scapulae. Thus as you begin the pull-down these muscles undergo a strong contraction to rotate the scapula downward which, in turn, allows the arm to move downward. Without this synchronized action, you would not have a smooth movement and the chances of shoulder injury would be increased. Also, since the rhomboid lies under the trapezius, its development adds considerable muscle depth to the middle of the upper back. 6) In the pull-up the biceps is not involved in the pull-up action. However, the brachialis and brachioradialis under strong tension to help stabilize the elbow joint during the pull-up. They are assisted in elbow stabilization by contraction of the triceps, whose long head also assists in the pull-up (shoulder joint adduction). Some bodybuilders strongly believe that the biceps plays a major role in this exercise but you can test this very easily. Make a strong contraction of the biceps so that you can see the muscle peak. Now turn the palm of the hand away and the biceps “disappears.” Thus in the pulldown since you are using a pronated grip, the biceps is not involved. Note, however, that in the chin-up the biceps as well as the brachialis and brachioradialis are strongly involved in elbow flexion. 7) The pull-up, although a great exercise, is often not practiced by beginning bodybuilders and athletes because of its difficulty. Keep in mind that you must raise body weight on each repetition, which, at times, can be quite great. Because of this, the lat pulldown is often preferred. But when a pull-down machine is not available, there is still another way that you can practice the pull-up to develop the muscles without lifting total body weight. To do this it is necessary to lower the horizontal bar to chin or chest level while still in a standing position. If the bar is not adjustable, you can use Backmaster handles, which you can attach to a door and then set the handles to chin/chest height. Grasp the handles in a pronated grip, lower the body until the arms are fully extended and then pull with the arms and use the legs, when necessary, to help raise body weight. In this way you can still get an effective stretch of the shoulders and you can adjust the effort between the arms and the legs to successfully do the exercise. If you use the neutral grip with the Backmaster handles, it provides a very effective low back stretch. Because of this it is used by many bodybuilders and athletes to get a total spine stretch in the morning and evening, especially after doing heavy workouts that compact the spine.