Pec Tendon Tears - Some Exercise Science
  • Dr. Thomas Falls, MD

Pec Tendon Tears - Some Exercise Science

For those of you who know me, I have become quite an avid fan of Crossfit over the past year. It has helped me to get in shape and gain tremendous strength (and undo the physical toll residency took on me). It's a fun, team environment and all-in-all I couldn't recommend it enough. However, as the regional games are currently coming to a close, I couldn't help but be bothered by a disturbing number of the same injury in quite a few elite male athletes. At least 4, possibly up to 6 men tore their pectorals major tendon while doing ring dips as a part of the workout. See here: Torn Pecs Decimate the East Regional Men’s Field. See picture of what a ring dip is below.

Why this has happened may be up for some debate, but I have a good idea as to what happened. The standard for the ring dips lead to at least 90 degrees (or more) of elbow flexion and maximum scapular retraction at the bottom of the dip. While doing doing multiple rounds of this exercise for time, it was common to drop quickly into the dip before pushing back up (extending the arms - using the pectoral muscles and triceps). This quick deceleration/acceleration leads to a significant eccentric-concentric muscle contraction, and can potentially be a setup for injury. Now I'm not casting any blame here, these things happen. Injuries happen in all sports as athletes push themselves to be better. It is curious that this only happened in male athletes - one theory I heard at my gym this weekend is that women tend to have better flexibility than men. Combined with (generally) smaller mass, this puts less stress on the tendons. It may be worth revisiting this standard in the future, or simply programming more pec-heavy exercises into Crossfit workouts to better prepare for this movement.

Now, onto the exercise science part of this - so what is an eccentric contraction? Basically this means that the muscle is firing while it is still elongating. - such as doing "negative" biceps curls and slowly allowing the arm to straighten was still keeping tension in the muscle. Concentric is just the opposite - a "regular" biceps curl where the muscle is shortening during the contraction. See the diagram below for a pretty nice explanation.

Now don't get me wrong, eccentric exercises are great. They help to build muscle and are an important part of rehab protocols. But, they do tend to cause some muscle damage, and have the highest risk for delayed onset muscle soreness (DOMS) - so you may be very sore 1-2 days after your eccentric heavy workout. This is because doing these exercises actually causes micro-tears in the muscle, and when your body repairs the damage you build (hypertrophy) your muscles. Where the bad injuries occur with eccentric contractions during very quick, high force activities. Most orthopaedic surgeons have seen this manifest as distal biceps tendon ruptures. A person trying to catch themselves while falling (or catch an object that is falling) leads to an elbow that is forcefully extended against a contracting biceps and POP - the distal biceps tendon ruptures. Assuming the reports are correct, most of the affected athletes will need surgery to repair the pec tendon - usually with heavy suture and anchors. If the tear is partial, it could potentially be treated non-operatively.

I will leave you with an interesting scholarly article I found from the physical therapy/sports medicine literature on the role of eccentric exercises and injury prevention. Eccentric Muscle Contractions: Their Contribution to Injury, Prevention, Rehabilitation, and Sport (PDF file)

#Crossfit #Tendonrupture #exercisescience