вторник, 24 мая 2016 г.

BLAST CHEST & BACK WITH STRAIGHT-ARM DUMBBELL PULLOVERS

Written by Stephen E. Alway, Ph.D., FACSM
 
16Pullovers-dumbbells

Blast Chest & Back with Straight-Arm Dumbbell Pullovers



Lifting heavy dumbbells for upper body training may seem like a throwback to the pioneer days of bodybuilding. However, upper body mass building lies less in chrome machines and more in grit and determination to grind through the heavy resistances of free weights. Machines have their place of course, but some of the muscle stimulation patterns of free weights are rather hard to duplicate with chromed machines. If you are stuck in the machine age and are not interested or motivated enough to explore hard training with free weights, or if you are already satisfied with your upper body width and thickness, then there is little need to read further. However, if you have the guts to face a hard challenge and try new things to achieve your goals of possessing an untouchable upper body, then straight-arm dumbbell pullovers are for you.
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Muscle Structure and Function
Straight-arm dumbbell pullovers will lock in your latissimus and pectoralis muscles1 and the smaller serratus anterior muscles, which highlight the chest and lats from the front for an overall upper body blitzing approach to widen the chest and thicken the back and shoulders. The fibers of the latissimus dorsi muscle extend from the lower thoracic vertebrae and the iliac crest of the hip, and the fibers come together at the upper portion of the humerus bone of the upper arm near the shoulder.2 The latissimus dorsi muscle extends the humerus by pulling the upper arm backward. In addition, it adducts the humerus bone by bringing the arm towards the center of the body. When the arms come directly over the head as in straight-arm dumbbell pullovers, the middle and lower parts of the latissimus are activated most effectively. 

The pectoralis major muscle of the chest is also activated as the dumbbell is being moved from over the head to the chest in pullovers.1 The pectoralis major runs from the clavicle, manubrium (the top portion of the sternum), the upper costal cartilages, and the upperparts of the external oblique muscle to the head of the humerus bone of the upper arm near the shoulder joint.2 The pectoralis major adducts the humerus (draws the arm towards the midline of the body). The serratus anterior muscle attaches to the lateral side of the ribs.2,3 Its fibers anchor on the first eight ribs and then run posteriorly along the lateral side of the thorax. The other end is attached along the medial border of the scapula (shoulder blade).1 It pulls the scapula forward (protraction) and holds it against the thoracic wall, which is important during pushing and throwing movements.4,5,6   

The abdominal muscles stabilize the upper body during pullovers. The rectus abdominis runs from the pelvis to the base of the sternum.2 The external oblique runs from the fifth through the 12th ribs, down to the pubic and the iliac bones of the pelvis. When both left and right sides of the external oblique muscles and the rectus abdominis shorten, they flex the trunk so the head moves towards the feet.2
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Dumbbell Pullovers: Execution
1. Place a dumbbell on its end at one edge of a flat bench. Lie 90 degrees to the long axis of the flat bench. Your shoulders and upper back should contact the bench, and your feet should be placed flat on the floor. Your neck and head should be just off of the bench. 

2. Grasp one end of the dumbbell with your palms facing the ceiling, so that you form a diamond between the thumbs and fingers of each hand (one hand completes one-half of the diamond). Position the inside plates of one end of a dumbbell against the palms of your hands, so the shaft of the dumbbell sits in the “diamond” created by your hands. Lift the dumbbell over the chest; this is your starting and finishing position.

3. Straighten the elbow joints, then slowly lower the dumbbell from a position that is over your chest, to an arc that moves backwards over your head and then behind your neck. Drop your hips towards the floor as the weight goes over your head to increase the stretch of your rib cage.

4. Stop the descent of the dumbbell when your upper arm forms a straight line through the shoulder to the armpit. Keep the elbows locked as you lower the weight. 

5. In the lowest position, your triceps should be in the same plane as your nose. From this position, slowly raise the weight in an arc back over your chest to the starting position. 

6. You should inhale forcefully while you are lowering the dumbbell behind your head and towards the floor.7 Forcefully exhale near the top of the movement, when the weight is over the chest.7

Ensure that the motion of the dumbbells is slow and controlled to minimize the stress of the delicate rotator cuff muscles of the shoulder. Similarly ensure that you finish with the weight over your chest and never lower the weight on the floor behind your head because this will place excessive stress on your rotator cuff muscles.

The serratus anterior muscles are activated as the arms are being lowered, because the scapula is protracted during this phase. The lower fibers of the pectoralis major and the latissimus dorsi muscles are hammered as well during the upward trajectory of the dumbbell. Even the rectus abdominis and oblique muscles of the abdomen are recruited during the upward movement of the dumbbell. The costal cartilages that attach the ribs to the sternum are stretched as the dumbbells are lowered and this stretch is increased as the hips are lowered. You will quickly find that old school straight-arm dumbbell pullovers will make a huge impact on achieving unprecedented torso depth and chest circumference for a superior upper body.

References:
1. Marchetti PH, Uchida MC: Effects of the pullover exercise on the pectoralis major and latissimus dorsi muscles as evaluated by EMG. J Appl Biomech 2011;27:380-384.
2. Moore, K.L. and A.F. Dalley II. Clinically oriented Anatomy. Fourth Edition. Baltimore, Lippincott Williams & Williams, 1999; pp. 690-697.
3. Agur, AMR and MJ Lee. “Grant’s Atlas of Anatomy. Tenth Edition. Philadelphia. Lippincott Williams & Wilkins 1999; pp. 442-453.
4. Ha SM, Kwon OY, Cynn HS et al: Comparison of electromyographic activity of the lower trapezius and serratus anterior muscle in different arm-lifting scapular posterior tilt exercises. Phys Ther Sport 2012;13:227-232.
5. Chelly MS, Hermassi S, Shephard RJ: Relationships between power and strength of the upper and lower limb muscles and throwing velocity in male handball players. J Strength Cond Res 2010;24:1480-1487.
6. Andersen CH, Zebis MK, Saervoll C et al: Scapular muscle activity from selected strengthening exercises performed at low and high intensities. J Strength Cond Res 2012;26:2408-2416.
7. Caruana-Montaldo B; Gleeson K; Zwillich C: The control of breathing in clinical practice. Chest 2000; 117: 205-25.

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