What is the Pec Muscle and Why was It Injured During CrossFit Regionals?

Pectoralis Muscle, pec major, pec minor, physical therapy


The pectoralis major, or pec major, muscle attaches to your sternum and collar bone on your chest and connects to a grove on your upper arm. It is responsible for four primary motions:

  1. Horizontal Adduction: bringing your arm across your chest
  2. Internal rotation: rotating your shoulder inward toward your chest
  3. Shoulder Extension: pulling your arm down and back behind body
  4. Shoulder Flexion: pulling your arm up overhead

Don’t forget about the pec minor! The pec minor runs from your upper ribs to your shoulder blade. It is helps move your shoulder blade down and closer to your body when you move your arm. This allows for more fluid arm movements.


Weightlifters are the most common population at risk for this injury. Even in this population it is rare to fully tear the pec major (about 100 people every 20 years). However, at this year’s CrossFit Regionals there were 30 pec injuries in just three weekends. These events highlight the importance of taking care of your chest muscles, and preventing a traumatic injury like this.

There are two ways your pec muscle can be injured:

  1. Traumatic incident: an extreme blow to the upper body in sports like football or boxing.
  2. Overuse Injury: overload to the muscle tissue of pec major from exercises like bench press or ring dips

A complete or grade 3 pec major tear would exhibits:

  • Bruising and swelling in upper chest and arm
  • Searing pain in chest area
  • Extreme loss of strength/difficult moving in horizontal adduction, internal rotation, shoulder extension and shoulder flexion

A complete tear usually requires surgery and months of therapy, and often athletes never regain same level of strength in the chest.

Did you know that pesky pec minor can also be a contributing factor in shoulder impingement, upper crossed syndrome, and other scapula movement problems? Even though the pec minor isn’t directly responsible for arm movements, it’s a common cause of shoulder pain. Pay attention to those pecs!


Symmetry Physical Therapy explored the importance of prehab a few months ago on our blog and the CrossFit pec injuries have proven the importance of prepping your body for exercise. Warming up and activating a muscle before exercise and strengthening it throughout its entire range is the best way to prevent injury. Here are two great activation exercises for the pec:

  1. Pectoralis Major Doorway Stretch:
  • Standing with feet staggered one in front of the other, press one elbow and forearm against the wall.
  • Keeping chest facing forward lean forward and activate back muscles to stretch the pec muscle of the arm against the wall
  • Hold stretch for 30 seconds on each arm

2. Isometric Internal Rotation

  • Find a corner of a wall or any hard surface and press forearm against it as if trying to push your arm in towards your belly button
  • Your elbow should be bent at 90 degrees when performing this
  • Perform 10 second holds 3x on each arm.

Activating the pec before a workout is essential. However, it’s also important to incorporate exercise variation, rather an movement variation, into your workouts. This means that every time you perform a ring dip, you perform it with slightly different grips–wider or tighter– or have the rings more or less slack. That way, your body is prepared for all variations of that exercise. Exercise variation applies to all movement. It is s important to strengthen muscles across their entire functional range of motion preventing weak spots and injury.


Pec Muscle, Pec Injuries, CrossFit Regionals

Unfortunately for some of the competitors, they likely acquired their pec injuries from under-preparation and overuse during competition. At the games, the rings were wider and more slack than most training facilities. This setup required more stability through the shoulders and more strain on the pecs to complete ring dips. To avoid injury, these athletes needed to not only train press exercises and ring dips, but all variations of these movements.

Prehab is an aspect of physical therapy we are focused on at Symmetry Physical Therapy. Our goal is to help you prep your body with mobility, stability, coordination, balance, strength, agility…you name it…before an injury, like a torn pec, even has the chance to sneak up. Come in for an assessment to see where you’re at now, so we can figure out how to make you even better! Give us a call us 305.331.2277. We can’t wait to show you what prehab is all about!

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