Integrating Japanese Eastern medicine with Western medicine.

Posterior Exterior Chain（PEC)

PEC (Posterior Exterior Chain)

PEC (Posterior Exterior Chain) is another term used in Postural Restoration Institute®. This chain of muscles are to be exterior (outside) global musculature and tighten or lock your body.

PEC-pattern in Golfer

Muscles: Latissimus Dorsi, Quadratus Lumborum, Posterior Intercostals, Serratus Posterior, Iliocostalis Lumborum

All human beings have underlying an L AIC pattern (except for a person who is born with situs inversus). some individual is going to move into a PEC pattern because of lifestyle habits (how much they sit, stand, gait, etc), genetics (such as hypermobility), previous injury & the need to compensate around them, and exercise/sports habits.

In PRI, imbalances or dysfunctions in the Posterior External Chain (PEC) can lead to a range of symptoms, including:

  1. Low back pain: When the muscles of the PEC are dominated and imbalanced, they can put increased stress on the low back, leading to pain and discomfort.
  2. Hip pain: Dominance in the PEC pattern can also affect the hips and cause pain in this area.
  3. Knee pain: Dominance and imbalances in the PEC can also contribute to knee pain, especially in athletes who place a lot of stress on their knees during activities such as running or jumping.
  4. Foot and ankle pain: The muscles of the PEC also affect foot and ankle function, so dominance and imbalances in this area can lead to pain in the feet and ankles.
  5. Postural imbalances: The PEC plays an important role in posture. Overworking PEC musculature can lead to poor posture and an increased risk of injury.
  6. Reduced athletic performance: Cveracting PEC can affect athletic performance. It especially inhibits the movement of alternation and reciprocation. Therefore activities related to frontal and horizontal planes are severely limited. 
Sub-Optimal ZOA cited from www.posturalrestoration.com

It’s important to note that these symptoms can be caused by a variety of factors, and a proper assessment by a qualified healthcare professional is necessary to determine the underlying cause and develop an appropriate treatment plan.


FuncPhyiso is only physical therapy clinic in Manhattan, NY officialy certified as a Postural Restoration Center.

In my personal experience (seeing patients in NY and TX), I see more patients with L AIC or the extension of L AIC pattern in TX than in NY. On the other hand, I see more patients with PEC and the extension of the PEC pattern in NY than in TX. I believe this is because of differences in lifestyle, health awareness, and exercise habits.

In the PEC pattern, those muscles become tightened and lock your body. They compress the back side of our body and pull the pelvis forward on both sides.  As a result, we often see severe anterior pelvic tilts, excessive lumber curvature, and forward shift of the pelvis.

Ron Hruska, PRI, annual workshop at FuncPhysio NY. A patient with PEC with anterior occlusion guidance with airway issues. Ron created a temporal sensory device to reduce his neck tension as well as open his airway.