Fixing the Flaws: Weak Rotator Cuff / Scapular Stabilizers
Posted Aug 26 2008 4:30pm
I group these two together simply because they are intimately related in terms of shoulder health and performance.
Although each of the four muscles of the rotator cuff contributes to humeral motion, their primary function is stabilization of the humeral head in the glenoid fossa of the scapula during this humeral motion. Ligaments provide the static restraints to excessive movement, while the rotator cuff provides the dynamic restraint. It's important to note, however, that even if your rotator cuff is completely healthy and functioning optimally, you may experience scapular dyskinesis, shoulder, upper back, and neck problems because of inadequate strength and poor tonus of the muscles that stabilize the scapula. After all, how can the rotator cuff be effective at stabilizing the humeral head when its foundation (the scapula) isn't stable itself? Therefore, if you're looking to eliminate weak links at the shoulder girdle, your best bet is to perform both rotator cuff and scapular stabilizer specific work.
In my experience, the ideal means of ensuring long-term rotator cuff health is to incorporate two external rotation movements per week to strengthen the infraspinatus and teres minor (and the posterior deltoid, another external rotator that isn't a part of the rotator cuff). On one movement, the humerus should be abducted (e.g. elbow supported DB external rotations, Cuban presses) and on the other, the humerus should be adducted (e.g. low pulley external rotations, side-lying external rotations). Granted, these movements are quite basic, but they'll do the job if injury prevention is all you seek. Then again, I like to integrate the movements into more complex schemes (some of which are based on PNF patterns) to keep things interesting and get a little more sport-specific by involving more of the kinetic chain (i.e. leg, hip, and trunk movement).
On this front, reverse cable crossovers (single-arm, usually) and dumbbell swings are good choices. Lastly, for some individuals, direct internal rotation training for the subscapularis is warranted, as it's a commonly injured muscle in bench press fanatics. Over time, the subscapularis will often become dormant – and therefore less effective as a stabilizer of the humeral head - due to all the abuse it takes.
For the scapular stabilizers, most individuals fall into the classic anteriorly tilted, winged scapulae posture (hunchback); this is commonly seen with the rounded shoulders that result from having tight internal rotators and weak external rotators. To correct the hunchback look, you need to do extra work for the scapular retractors and depressors; good choices include horizontal pulling variations (especially seated rows) and prone middle and lower trap raises. The serratus anterior is also a very important muscle in facilitating scapular posterior tilt, a must for healthy overhead humeral activity. Supine and standing single-arm dumbbell protractions are good bets for dynamically training this small yet important muscle; scap pushups, scap dips, and scap pullups in which the athlete is instructed to keep the scapulae tight to the rib cage are effective isometric challenges to the serratus anterior.
Concurrently, athletes with the classic postural problems should focus on loosening up the levator scapulae, upper traps, pecs, lats, and anterior delts. One must also consider if these postural distortions are compensatory for kinetic chain dysfunction at the lumbar spine, pelvis, or lower extremities. My colleague Mike Robertson and I have written extensively on this topic. Keep in mind that all of this advice won't make a bit of difference if you have terrible posture throughout the day, so pay as much attention to what you do outside the weight room as you do to what goes on inside it.