The X-Factors and Movement

Anterior X-Factor

All motions involving rotation and extension run along the Anterior X-Factor. When viewing the anatomy of the adductors to the opposite pectoral and shoulder region, there is a relatively parallel line along these tissues. This Flexibility Highway runs from the adductor insertion on the linea aspera on the posterior femur and originates at the pubis ramus on the pelvis.

At this point, there is a close fascial relationship between the origin of the adductors to the rectus abdominis, as it traverses along the abdominals to the opposite intercostals and obliques, upward to the serratus anterior, into the pectorals and into the opposite shoulder complex. Therefore, any motion that involves extension and rotation to the opposite side runs along the Anterior X-Factor. Additionally, if the client abducts and extends his or her arm similar to a throwing motion or golfer’s backswing, the tissue from the deltoid into the bicep and forearm becomes included into the Anterior X-Factor. Therefore, it is crucial to possess ample mobility in the adductors, abdominals, and pectoral regions to enhance motions through the Anterior X-Factor. Likewise, it is highly advised the client maintain good range of motion in the hamstrings, as these tissues are the “neighbor” of the adductors and highly affect them.

An interesting argument can be made that the hamstrings are greatly impacted by the AXF, as the adductors are close neighbors to the hamstring complex. With understanding of the fascial lines, we then must draw a conclusion if the hamstrings are close friends to the AXF, then the calf group must be as well, as the gastrocnemius and hamstrings are connected at the posterior knee.

To demonstrate the need to stretch the AXF in a unified approach, consider the actions of throwing athletes, such as a pitcher, as they start a windup in the throwing motion. As a right-handed pitcher’s right arm extends back during the windup or cocking phase, the left hip will move into an external rotated position to the torso. When looking at the global action, the left hip is rotated outward, while the torso is turned to the right. The right arm shoulder is extended away from the torso, and a line from the left hip, through the abdominal complex, into the right shoulder complex is created. The general action is rotation and extension, which are the key reactions through the Anterior X-Factor. A similar reaction occurs during the backswing of a right-handed golfer.

Posterior X-Factor

Viewing the posterior architecture of the soft tissue, notice the nearly parallel line between the opposite gluteal complex and latissimus dorsi. Both tissues entwine into the lumbosacral fascia, thereby joining the opposite hip and shoulder. The importance of the PXF comes into play with flexion and rotational actions, such as the follow through in a throw, golf swing, tennis swing, or simply picking up an object that is lateral and within reach.

In movement, a very important principle must be at the forefront of strategies, that is, the two most mobile regions of the body are the hip complex and thoracic spine. This principle becomes very evident through the X-Factors because a rotational action is an integral aspect of these Flexibility Highways. If there is inadequate available motion in either the hips or thoracic spine, the rotation will be compensated through the lumbar spine. This potentially can be very detrimental to spine health, as rotation in the lumbar spine is approximately 13-15 degrees in the transverse plane. Therefore, a goal of Anterior and Posterior X-Factors is to gain motion in all three planes of movement prior to working through these particular Flexibility Highways.

One last point, when working clients through the X-Factors, I suggest gaining the motion through the Anterior X-Factor first.  There is less rotational actions through the Anterior X-Factor because the hips and shoulder are usually not rotated opposite each other as they are in the Posterior X-Factor.  Gain the motion in the hips and thoracic spine before commencing into the Posterior X-Factor.

Good luck and please let us know how this works for your clients!

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Human Motion Associates is dedicated to understanding the reactions of muscles and joints to improve efficiency of performance through movement science. Our goal is to enhance health through activities of daily living.

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