Written by Stephen E. Alway, Ph.D., FACSM
Develop a Thick Chest with Machine Pullovers
Rarely has a human come along with a barrel-like chest that captured more unbelievable depth than the chest that belonged to Mr. Universe, Reg Park. The side chest shot that belonged to Park was mind-blowing, and in fact huge enough to capture the imagination of a young Arnold Schwarzenegger, who developed a pretty decent side chest shot himself. If you have come to realize that your chest is not as large as you want, it is probably a great time to find an exercise that will cause your chest to explode with size from the inside out. Exercises like machine pullovers can begin a transformation in your chest structure that will seemingly erupt with an explosion of growth. Not only will machine pullovers challenge your chest structure, but the muscles packing over your back and chest will be forced to thicken and grow.
The rib cage protects everything important in your chest, but it also supports the muscles that make your torso look great. The portion of the rib that attaches to the sternum (breast bone) is not bone, but costal cartilage (“cartilage of the ribs”). This costal cartilage provides the elasticity to the chest, and allows the ribs of young adults to “give” rather than fracture under a blow or compression. This elasticity permits some stretching in the costal cartilages (e.g., by training)— thereby increasing the diameter of the rib cage. The costal cartilage will harden by approximately age 25, so expansion of the rib cage via stretching the costal cartilages becomes almost impossible for people older than that.
There are three layers of intercostal muscles, and they lie between adjacent ribs. From deepest to most superficial, they are the innermost, internal and external intercostal muscles. The innermost and internal intercostal muscles lie deep to and at right angles to the external intercostal muscles. All three muscles of this group are active during inspiration (taking in a deep breath) and expiration (exhaling that breath). If the intercostal muscles are developed to their maximum, the size of the rib cage is markedly increased during inspiration.
The serratus anterior is a large muscle that overlays the lateral parts of the rib cage and the lateral part of the intercostal muscles. The fibers of the serratus anterior muscle attach to the first eight ribs, and run posteriorly along the lateral side of the thorax. The other end is attached along the medial border of the scapula (shoulder blade). This muscle pulls the scapula forward (protraction) and holds it against the thoracic wall.
The latissimus dorsi and teres major musclesare strongly activated by machine pullovers. These muscles addimportant width to the upper back. The latissimusextends from the lower (inferior) thoracic vertebrae and the iliac crest of the hip to the upper (superior) portion of the humerus bone of the upper arm, near the shoulder. The teres major muscle begins on the inferior angle of the scapula (shoulder blade), but it attaches high, into the same region of the humerus bone of the arm as the latissimus dorsi. Together, the latissimus dorsi and teres major muscles extend the humerus from a flexed position (i.e., with the arm forward). These muscles are more completely activated with the arms at mid-chest level, or in work directly overhead. They are strongly activated with the arms abducted (wide apart) and therefore, machine pullovers are perfectly suited to activate the upper-back muscles.
The clavicular head of the pectoralis major lies along the anterior lower surface of the clavicle (collar bone). The sternocostal head of the pectoralis major begins along the manubrium (top portion of the sternum), the upper-six costal cartilages and the tendinous-like portion of the superior part of the external oblique muscle (a lateral muscle of the abdominal wall). Both heads converge on a groove near the head of the humerus. Both sternocostal and clavicular heads help to extend the humerus by moving the upper arm downward during the last one-half of the pullover.
1. Adjust the seat height so that your feet are flat on the floor, with knees bent to about 90 degrees. Some pullover machines have safety belts that will keep your hips on the seat.
2. Press your elbows into the pads. Take a breath, and then exhale as you press your elbows forward and downward in a controlled and deliberate fashion. Press your elbows down as far as you can. Do not try to do the exercise explosively, because your shoulder joints can be unduly stressed if you try to explode downward from a stretched position.
3. Inhale deeply as you slowly return your arms to the starting position. However, do not hit the weight stack on the bottom plates.
4. Hold the stretched position at the top for at least one full second, and then move into the next repetition downward. Rest only after you have completed a set of 8 to 12 reps.
You should always do some shoulder stretching before beginning this exercise— even if it is your final exercise. Injury-free shoulders will allow you to have the greatest range of motion on machine pullovers. This exercise activates the serratus anterior as the arms are being lowered, and when the scapula is protracted. The intercostal fibers and costal cartilages will be maximally stretched by the deep inspiration. The pectoralis major, the latissimus dorsi and teres major muscles are activated in this exercise particularly during the last downward part, and also when resisting the upward movement of the machine as the scapula is retracted (shoulder blades come closer together). Therefore, this is a great exercise to finish your chest or back workout.
Don’t be afraid of piling on the resistance in machine pullovers. A few months of consistent effort with good resistance will activate the beginnings of your chest explosion, so that you will be on your way to the largest barrel possible.
Agur, AMR and MJ Lee. “Grants Atlas of Anatomy.” Tenth Edition. Philadelphia. Lippincott Williams & Wilkins 1999, pp. 442-453.
Bull ML, Freitas V, Vitti M and Rosa GJ. Electromyographic validation of the trapezius and serratus anterior muscles in rowing exercises with middle and closed grip. Electromyogr Clin Neurophysiol, 43: 4-8, 2003.
Cannon DT, Grout SL, May CA, Strom SD, Wyckoff KG, Cipriani DJ and Buono MJ. Recruitment of the serratus anterior as an accessory muscle of ventilation during graded exercise. J Physiol Sci, 57: 127-131, 2007.
Cappello M and De Troyer A. On the respiratory function of the ribs. J Appl Physiol, 92: 1642-1646, 2002.
Moore KL and AF Dalley II. Clinically Oriented Anatomy. Fourth Edition. Baltimore, Lippincott Williams & Williams, 1999, pp. 690-697.
Schachter AK, McHugh MP, Tyler TF, Kreminic IJ, Orishimo KF, Johnson C, Ben-Avi S and Nicholas SJ. Electromyographic activity of selected scapular stabilizers during glenohumeral internal and external rotation contractions. J Shoulder Elbow Surg, 19: 884-890, 2010.
Uhl TL, Muir TA and Lawson L. Electromyographical assessment of passive, active assistive, and active shoulder rehabilitation exercises. PM R, 2: 132-141, 2010.