The Truth about Impingement, Part 1
By
Eric Cressey
Roughly 10–15 times per week, I get emails from folks who claim that they
have shoulder “impingement.” Honestly, I roll my eyes the second that I read
these emails. Don’t get me wrong—I’m not making light of their pain. It’s just
that it drives me crazy when doctors throw this blanket statement out there.
I will be 100 percent clear with the following statement—impingement is a
physiological norm. Everyone—regardless of age, activity level, sport of choice,
acromion type, gender, or you name it—has it. Don’t reach up to touch that mouse
on your computer. You’ll aggravate your impingement and your supraspinatus will
explode! And don’t scratch that itch on the back of your neck. Your impingement
will go crazy, and your labrum will disintegrate!
Don’t believe me? A 1994 study by Flatow and colleagues verified that
impingement was a physiological norm. Everyone gets it (1). Yes, this has been
out for almost 15 years now. So, the next logical question is why do some people
have pain with impingement while others don’t?
In reality, there are several factors that dictate whether or not someone is
in pain. They include:
- Tissue quality: The most “impinged” structures (typically the
supraspinatus, infraspinatus, and long head of the biceps tendon) are more
likely to break down in older age than they are in earlier years. Younger
individuals can regenerate faster even when overall stress on the tissues is
held constant. So how you handle a 50-year-old with “impingement” is going
to be somewhat different from how you handle a 15-year-old with
“impingement.”
- Degree of elevation: The more one abducts or flexes the humerus, the
greater the degree of impingement. This is why folks need to start in a more
adducted (arm at side) position early on in rehabilitation.
- Acromion type: Flat (type I) acromions have significantly less contact
area with the rotator cuff tendons than hooked (type 2) or beaked (type 3)
acromions.
These structures may change over time due to…
- Bone spurs: Bone spurs on the underside of the acromion will increase
the amount of impingement.
- Strength of the rotator cuff: The stronger the cuff, the better its
ability to depress the humeral head and minimize this impingement.
- Scapular stability: The more stable the scapula, the more likely it is
to posteriorly tilt and upwardly rotate effectively when the humerus is
raised into the zones of greater impingement. This scapular stability
includes adequate length of the downward rotators (pec minor, levator
scapulae, and rhomboids) with adequate strength of the upward rotators
(lower traps, serratus anterior, upper traps).
- Thoracic spine mobility: The posture of the thoracic spine dictates the
position of the scapulae, which, in turn, affects impingement as noted in
scapular stability.
Inside-Out is an awesome product for improving
thoracic spine mobility.
- Increased internal rotation: Certain movements that lock the humeral
head in internal rotation increase the degree of impingement during dynamic
activities. This is why some people can’t bench press early on in their
rehabilitation programs yet can do dumbbell bench presses with a neutral
grip pain-free. It’s also the reason why upright rows are a stupid exercise
in my opinion.
- Breathing patterns: Think about what happens when someone becomes a
“chest breather.” The shoulders shrug up and you get extra tightness in the
levator scapulae and sternocleidomastoid (among other muscles). In the
process, the degree of impingement can increase.
- Other issues further down the kinetic chain: I could go on and on about
a variety of issues in this regard, but it’s impossible to be exhaustive so
I’ll just give a few examples:
If someone has poor core stability in the sagittal plane that is
manifested in an inability to resist the effects of gravity during a
push-up, the hips will “sag” to the floor. As this happens and the
upper body remains strong, the scapulae are shifted into an
anterior tilt, which increases the amount of impingement on the rotator
cuff. So, weakness and/or immobility in other areas can certainly predispose
an individual to shoulder problems.
This can also be carried forward to baseball pitchers. We know
that shoulder problems are more likely to occur in throwers who have poor
lead leg hip internal rotation and knee flexion range-of-motion because
it causes the stride leg to open up early, leaving the arm “trailing
behind” where it should be.
Speaking of pitchers, a phrase that has been coined with respect to the
“unique” kind of impingement you see in them is “internal impingement.” In Part
2 of this article, I’ll discuss the different kinds of impingement and why it’s
still a cop-out diagnosis for any health care professional to just say that you
have one or the other rather than tell you explicitly what dysfunctions need to
be addressed.
References
1. Flatow EL, Soslowsky LJ, Ticker JB, Pawluk RJ, Hepler M, Ark J, Mow VC,
Bigliani LU (1994) Excursion of the rotator cuff under the acromion. Patterns of
subacromial contact. Am J Sports Med 22(6):779–88.
Eric Cressey, MA, CSCS, is the president and co-founder of Cressey
Performance, a strength and conditioning facility in Hudson, Massachusetts.
While Eric deals with a wide variety of athletes, he has become most well-known
for his work with baseball players. In the 2007-2008 off-season alone, Cressey
Performance saw 96 baseball athletes from 32 high schools, 16 colleges, and
eight major league organizations (www.CresseyPerformance.com).
Eric has authored three books and more than 200 articles and co-created two DVD
sets. A world record holding competitive powerlifter himself, Eric publishes a
free, weekly newsletter and a daily blog at
www.EricCressey.com.
Elite Fitness Systems strives to be a recognized leader in the strength
training industry by providing the highest quality strength training products
and services while providing the highest level of customer service in the
industry. For the best training equipment, information, and accessories, visit
us at www.EliteFTS.com.
