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Rest Day

Your Rotator Cuff
By Coach Fox

Pretty often I hear these things…”I think it’s my rotor cuff”, or “rotary cuff”, or some other well intentioned but ill informed self-diagnosis. So let’s take a look at what the rotator cuff really is. Simply speaking, the rotator cuff is made up of 4 small muscles and their respective tendons. The main job of the rotator cuff is to optimally position and stabilize your humeral head within your glenoid fossa (or the ball at the top of your arm into the socket in your scapula) so that the larger muscles at the shoulder can do the real work.

Meet your rotator cuff (RC):


Supraspinatus  - Initially ABducts your arm (raises to the side, away from the body)
Infraspinatus – Externally rotates the arm
Teres Minor – Externally rotates the arm
Subscapularis – Internally rotates the arm

     Remember that while these are the joint actions the muscles of the RC effect, their main job is positioning and stabilizing. They are small muscles that cannot move much load. At first glance it seems that external rotation has an unfair advantage over the others. In fact there are larger “mover” muscles that also internally rotate the arm (pecs and lats mainly) and can overpower the small external rotators.  In CrossFit we intentionally focus on compound, functional movement, and that includes lots of push-ups and pull-ups (read, pecs and lats). So what winds up happening in many of us is that internal rotation at the shoulder overpowers external rotation. This is on display anytime an athlete’s drop in and their elbows flare out during a DB Thruster or Push Press or the like. They don’t have enough external rotation force being generated to stabilize the arm. Enter the justification of isolation exercises.

Here’s a great movement to strengthen external rotation. Position yourself you’re your torso pretty horizontal to the ground as in the photo. Start with a light DB or change plate held at arms length toward the floor. Pull your elbow up until it is in the plane of your torso. Then, keeping your upper arm in the same plane, externally rotate at the shoulder until your forearm is in the same plane as your torso and upper arm (Think of your elbow pointing a laser straight out to the wall and not letting it deviate). Then reverse the motions in opposite order.



If you're not sure about your technique on this move, don't hesitate to ask any of the coaches at the gym.


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Reader Comments (8)

Last night after classes:

4 Rounds1 Minute Row, max calories1 Minute Sit-ups, max reps1 Minute rest

I left my numbers on the whiteboard! but they were roughly20-25 cals on each row30 Sit-ups each round

Felt a little queazy after this
August 6, 2010 | Unregistered CommenterDavid Osorio
Great essay Coach Fox! Super interesting and helpful.

Yesterday: Clean practice with Brian D. Lots of fun and excellent coaching. Thank you Brian. Sets with the 33lb bar, then sets of 3 and 4 at 35 kilos, then 37 kilos, then 39 kilos. I have no idea how many sets I did at each weight. I was focusing on the moment of direction change from the explosive kick in the second pull to getting under the bar.

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August 6, 2010 | Unregistered CommenterLaurel
Here here on the essay Fox! Yet another reason this box distinguishes itself from others.
August 6, 2010 | Unregistered CommenterDeb
Better stop using those iPods in the gym. This lady might come visiting:

August 6, 2010 | Unregistered CommenterSamir Chopra
WU1500m row 18s/m incr every 500m. 2:10 - 1:50droms

WOD16:28 as rx'dhad my arse handed to me on this one.rope climb was good. farmers carry was hard. grip was going at the end.step up broke up into 10's. 20 burpees!goblet sq. sets of 20. 5 burpees

me likee that and this...

ACC WK400m Prowler push with 2x45lb plates with Dan for time.6:48

saw the new cfsbk t's. very nice.

August 6, 2010 | Unregistered Commenter.DMG
10:50 @ 35 lbs. Climb felt good. Fouled 5 times. Twice on the walk. 3 times on the step ups. Squats were unbroken.

There was no way to do this without the burpees. I don't think i could have simply stood there for 10 mins holding the dumbells.
August 6, 2010 | Unregistered CommenterJason
Nice write up Mr. Fox--thanks!Day 6 of my self imposed 30 day yoga-on-the-road challenge. Part of my focus on flexibility. Today's session was done in a Red Roof Inn in West Virginia. Trying to get in whatever additional kind of workout I can.

Impressions from the road--The U.S. is an amazing, diverse and wonderful place in way too many ways to count. Anyone that doesn't experience as much of this country as possible is really depriving themselves!
August 6, 2010 | Unregistered CommenterDavid Mak
Coach Fox, thank's for the External Rotation exercise. I saw it on the affiliate blog. I've been fighting with the lack of a front squat rack for a long time, and finally decided at the beginning of the month to start tackling this inability to get into that position.

I've been doing a lot of t-spine work, lat stretches (internal rotators), and the broomstick stretch (external rotator). This could help out too.
August 9, 2010 | Unregistered CommenterBo Boland

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