Part 1 of this article discussed the biomechanics of the foot, lower extremity, and hip. This second portion of the article will explore the lumbar, thoracic and cervical spine and shoulder girdle. As you read, you should start to appreciate the interaction and interdependency of adjacent joints upon other joints for efficient and economical movement. If you have not read “ 3-Dimensional Joint By Joint Approach to Movement, Part 1 ,” I suggest you do so prior to continuing this exploration of human motion.
The Lumbar Spine
The lumbar spine is the nemesis of all fitness and health professionals. Approximately 80% of the population will suffer from low muscular back pain at some point in their lives.
Before describing lumbar spine movement, let’s review a foundational concept relating to back movement: Spinal motion is described as the proximal bone in relation to the distal bone. This is the opposite of motion in the joints of the extremities, which was described in Part 1 as the distal bone in relation to the proximal bone.
In the photos below (which were also seen in the first part of this article), Figure 9.1 shows left cervical rotation because the proximal segment is rotated further to the left than the segments below it. However, Figure 9.2 demonstrates left cervical rotation because the proximal cervical segments are still further left than the distal vertebra below. This position shows the body is rotated right. However, according to our foundational concept, this translates to left cervical rotation.
The entire spine can be difficult to visualize three-dimensionally, but it is very worthwhile to do so. When thinking about the segmental position, you must think how motion is affected from the bottom up as well as top down. I often imagine the spine as a spiral staircase that has vertical, rotational, and lateral components to it. However, this must be thought of as the body moves and is impacted by the pelvis and arm motion.
We will view the lumbar spine from the position in gait with the left foot and right arm forward just prior to the right heel elevating off the ground.
As the left leg swings forward, it “pulls” the left hip forward. As the left foot hits the ground and the foot pronates, the leg internally rotates. As our foundational concept dictates, we now have internal rotation of the left hip as the distal bone (the femur) is internally rotated on the pelvis. At the same time, the pelvis turns to the right. Therefore, as the pelvis is turned right, the sacrum is on a right obliquity as well. The sacral facets of S-1 “carry” the fifth lumbar facets to the right, the fourth follows and so on up the lumbar spine. Keeping in mind that the right arm is forward with a contralateral reach, the thoracic spine is rotating left due to the right arm, and the shoulder is forward, causing the thoracic spine to be driven toward the left. There will be a transition point when the lumbar spine rotates less to the right at each segment the further upward toward the thoracic spine, and the thoracic spine will move less to the left as it moves downward toward the lumbar spine. Hence, there is an imaginary rotational line from the right extended leg and hip that goes from the low right quadrant of the body up and toward the left shoulder that is extended backward. The extension and rotation causes these two endpoints to be furthest from each other and allows the abdominals in the front to be eccentrically loaded from the right up the left. I call this the Flexibility Highways Anterior X-Factor. Additionally, however, the left gluteal complex is lengthened by way of the left hip, which is flexed and internally rotated. When viewing the right latissimus dorsi and posterior shoulder girdle, the right posterior side is eccentrically loaded from the lower posterior left hip up through the upper posterior right shoulder. These structures are connected via the lumbar fascia forming the Flexibility Highways Posterior X-Factor. In this orientation, the lumbar spine is extended and rotated to the pelvis in the sagittal and transverse planes. Refer to Figure 10 for visual application.
As the hip moves forward over the left foot during the mid-stance phase of gait, the right hip will drop a bit causing the left to be higher. The body will strive to keep the head and eyes level, similar to a bobble head doll: if you tilt the body on a bobble head doll, the head will tilt to stay level. This accommodation must be made through the spine. Therefore, the lumbar spine will laterally flex to the right. If this did not occur, the torso would lean to the opposite side of the higher hip — in this case, to the right. This frontal plane reaction allows the body to remain relatively upright and stable. Examine the photo in Figure 11 and consider what position the vertebral segments are in based on three planes of motion.
The spine reacts to the gait stride in the following tri-plane motions (assuming left foot in stride cycle):
- Spinal flexion at left heel strike in the sagittal plane. Spinal extension in relation to an extended hip in the sagittal plane as the right foot swings through during the gait cycle.
- Spinal rotation to the right, in the transverse plane, at right heel strike and mid-stance.
- Lateral flexion to the left in the frontal plane during right leg swing phase.
The Shoulder Girdle Complex
Most often, shoulder function connotes the shoulder joint absent of the shoulder girdle. In fact, many health and fitness professionals advise their clients to train their shoulder joints to be stable. I agree with this logic to a point, as we want to have stable shoulder joints, especially for those that participate in athletics such as baseball/softball, tennis, golf, javelin, and volleyball, just to name a few. In reality, all people need a degree of stability in the shoulder joint. However, there are other issues that affect shoulder function as well.
The shoulder is the most mobile joint in the body and is dependent upon a mobile scapula. The scapula has 19 muscles that attach to it and each one must be strong enough to withstand eccentric forces to allow the scapula to glide upon the ribs in all three planes of motion. Scapular motion is necessary to create an environment for the shoulder joint to function correctly. Many shoulder joint impingement issues are a result of the scapula not gliding properly and not allowing the greater trochanter to be clear from the acromion process, especially during shoulder abduction moments. Impingement is often the result of the lack of scapular motion or timing of the scapula moving while the humerus abducts causing a pinching of the supraspinatus tendon. Instead of focusing on the myriad of common shoulder injuries, this article will address the relationship of the scapula to the shoulder, as the scapular reactions are a result of body movements.
There is a saying I often use when relating to shoulder function, “Where the scapula goes, the humerus will follow.” In other words, humeral motion is greatly affected by scapular reaction. Likewise, the scapula is affected by humeral actions. However, if we step back from the shoulder girdle complex and globally observe the implications the body has upon the scapula, we will quickly sense that the scapula is dependent upon thoracic spine movement. If we delve deeper from a global perspective, the thoracic spine is greatly impacted by motion of the lumbar spine, which is impacted by hip motion. The hips, as we have observed, have a tremendous dependency upon foot function. Therefore, the scapula is a “floating” bone that is influenced by body motions.
Let’s now explore the distinct relationship between the hips and the scapula.
The scapula and shoulder girdle move in three planes of motion. Scapular reaction is typically an unconscious response to gravity, body position and angles, and segmental mobility. There is an important relationship between pelvic mobility and scapula motions. In the sagittal plane, when there is adequate hip extension, the scapula will depress and slightly retract. You can explore this by standing in a neutral, bilateral stance. Drive your hips forward, which creates a relative hip extension to the legs and spine. You will notice that the spine extends backward and the scapula depress and retract (see Figure 12). This reaction is due to the change of body position and angles that has allowed the scapula to react to gravitational forces pulling it downward. Next, keeping the arms relaxed, flex the spine forward to allow the hips to flex. Notice the scapula elevated and protracted; again, this is a response to body angles and gravity (see Figure 13).
Imagine how a person’s body angle and position changes and affects the scapula when they either have to reach into a cabinet that is overhead. He extends at the hip to allow the lumbar and thoracic spine to extend, creating an environment for the scapula to depress, for the acromion process to “clear” in the sagittal plane, and for the shoulder joint to flex. Likewise, if that same person now picks something up from the ground, the hips, lumbar and thoracic spines will flex, causing the scapula to elevate and protract to allow the humerus to successfully move.
Another example can be seen in bowling. As the bowler approaches her shot, she flexes at the hip and spine, allowing the scapula to elevate and retract while the shoulder joint extends. None of the above actions can be achieved efficiently, effectively, and safely without these synergistic responses. Now try any of the above movements and not allow the hips or spine to naturally move and feel the affect upon the shoulder joint. You will notice that the shoulder is not successful in the task and often feels a “jamming” sensation. Over many repetitions or years of dysfunction, this will lead to injury.
In the frontal plane, the same-side hip that adducts/abducts will cause the scapula of the corresponding side to adduct/abduct (see Figure 14). In other words, the opposite side hip that adducts will cause the opposite scapula to abduct. Of course, on the same side, the opposite joint that abducts will have an adduction moment on the opposite side.
I have observed many throwing injuries of the shoulder complex due to the lack of motion in the transverse plane. A key relationship exists between the opposite hip and shoulder during throwing-like actions, i.e. throwing, golfing, swinging a racket, and hitting a ball, to name a few. It is very important for the opposite hip to be able to attain a good range of motion during external rotation to allow the opposite shoulder to externally rotate. When the action occurs, the torso typically turns away from the opposite hip and toward the side of the affected shoulder joint. For example, when a right handed thrower is in the act of throwing, the body turns into the right hand and away from the left hip. This causes the right scapula to retract as it glides along the ribs. This is a very necessary action to create “clearance” of the sub-acromial space and reduce risk of impingement. I have seen numerous cases of lack of motion in the opposite hip and/or opposite shoulder through external rotation that has not allowed the shoulder to be clear of the acromion process during the throwing-like motion.
Likewise, I have evaluated many posterior shoulder issues that were a result of the clients’ inability to obtain adequate internal rotation of the opposite hip, which does not allow the leg, hip, and torso to decelerate the arm follow-through, thereby relying upon the posterior shoulder musculature to decelerate the arm action. If there is not enough left hip internal rotation for the right-handed thrower, the scapula will not be in a position of success in protraction and will cause improper arm slot positioning during the deceleration phase of throwing or other actions such as the follow-hrough in golf or in boxing.
Base upon the above description we can therefore describe the transverse plane relationship of the hip through the torso to the shoulder girdle, especially the scapula, as follows:
Figures 15 and 16 show how the opposite hip must externally rotate to allow the scapula to be mobile and retract, which will create successful shoulder joint external rotation. Likewise, however, the same-side hip must be able to attain adequate internal rotation to allow the same-side shoulder to externally rotate. In throwing motions, this is the load-up phase. The release point will demonstrate the body moving into internal rotation of the opposite hip and external rotation of the same-side hip to allow protraction of the scapula and internal rotation of the opposite side shoulder joint.
There must be mobility of various joint segments to allow the reactions to transpire, yet also stability to control and decelerate all these reactions that occur simultaneously. I have seen clients that are very well developed in the latissimus dorsi, which does not allow good rotation through the thoracic spine. In these cases, they are too stable and not mobile enough to accommodate the necessary transverse and frontal plane actions required for rotary activities.
To review the shoulder complex movement relationships:
- In the sagittal plane, the same-side hip that flexes will enhance scapular elevation and slight retraction to allow shoulder joint extension. Likewise, the same-side hip that extends creates an environment for the scapula to depress, retract and enhance shoulder joint flexion.
- In the frontal plane, the same-side hip that adducts/abducts will cause the scapula of the corresponding side to adduct/abduct.
- In the transverse plane, the opposite-side hip that externally rotates will cause the opposite scapula to glide on the ribs and retract, allowing the opposite-side shoulder joint to externally rotate. At the same time, the same-side hip will internally rotate to allow the same-side scapula to retract and shoulder joint to externally rotate. The opposite holds true for opposite hip/scapula/shoulder joint during the opposite motions.
So far the discussion of movement has had an impact upon joints and structures above and below the specified region. The cervical spine presents a slightly different perspective since the majority of its motion is often a result of actions that impact the cervical spine from motions that occur below it. The cervical spine often can liken itself to the bobble-head doll as it is impacted by body positions, angles, and motions that have a relative impact upon the c-spine.
The cervical spine is unique in that the lower portion from C3-C7 should maintain its inherent lordosis in order to serve as a shock absorber from forces generated from the regions of the body below it. The upper cervical spine, the cervico-occipital and C-1 do not have the ample tri-plane motion as the remaining segments possess, therefore, in order to preserve the upper cervical spine integrity and health, the lower cervical region requires its tri-plane motion.
The cervical vertebrae have an alignment that places each segment approximately 45 degree angular articulation to each other. When the cervical spine flexes, there is a gliding forward or opening of the proximal cervical segment upon the distal segments. Conversely, there is a closing of these segments upon return (relative extension) to the more neutral position or into extension. Therefore it can be viewed as not only flexion/extension, but also a gliding translation over a center of rotation as these motions occur. The upper cervical spine typically is conducive for flexion and extension, limited lateral flexion, and limited rotation. The lower cervical spine has more tri-plane actions, in fact, these actions require motion in all three planes simultaneously for successful movement. For example, cervical rotation to the right will cause the transverse processes of the c-spine to turn to the right. Concomitantly, there is a slight lateral flexion to the right in the frontal plane, and extension of the transverse process as well. Therefore, motion must occur in all three planes to allow a successful and efficient movement to occur. This does not consider the posterior translation required during this action.
Periodically a client presents with a straight or flexed cervical spine (see Figure 17). The fitness and health industry has addressed this in an isolated manner. If we step back for a moment to analyze the impact the body has upon the cervical spine, we will quickly notice that the posture of the body has affected the cervical spine. Assuming the cause is more soft tissue related than degenerative joint disease of the cervical region, most people that present with a flat cervical spine have a flexed thoracic spine and lumbar spine. If we view further distally, the pelvis typically is in a posterior tilted position.
To functionally improve the cervical spine, the lumbar spine must have a relatively extended position so that the lordosis is gained in this region, which will allow the thoracic spine to gain some degree of extension. This will create an environment for the cervical spine to be in a lordotic position, which will allow proper motion to occur.
A strategy that I have found successful is to have the client stand in a staggered stance and drive the hips forward (see Figure 18). This allows the extended hip to tilt anteriorly and the lumbar spine will extend in relation to the hip, thoracic spine will extend, scapula will retract along with the shoulder girdle, head will retract, and the cervical spine will be in an environment to regain its lordosis. Next, have the client reach the opposite side arm of the extended hip posteriorly. This retracts the scapula and enhances postural alignment.
To review the cervical region, the following concepts should be considered:
- Movement involves all three planes of motion.
- When movement occurs, there is a translation of the vertebral segments over the center of rotation.
- Make sure adequate motion exists within the thoracic spine for successful cervical movement.
Human motion is a complex synergy of tri-plane segmental actions performed to accomplish a specific task. The body’s reaction to those segmental motions is necessary for efficient and economical results. To fully assist our clients, health and fitness professionals need to develop strategies that address the problem, not the symptom, which the client possesses. We do a marvelous job at addressing the “what,” “when,” and “how” for program design. For instance, if a client has a knee problem, our industry inherently thinks that we are going to address the knee problem (what), by doing certain exercises with machines or body weight (how), and will plan this approach in a certain sequence of events (when). However, our industry does not address the “why” of the problem. In order words, if a client has an injury issue, particularly an overuse problem, the site of the injury is not the problem, it is the symptom. The problem is typically a joint level or two levels above or below the symptom.
We must step back and learn how the body moves through a three-dimensional approach and look at movement from a global perspective, not just a local one. When this paradigm is embraced, program design will take an entirely different approach. We will then be creating a truly personalized exercise prescription that addresses the limitations, compensations, and idiosyncrasies of our clients.
Take the time, be persistent, and good luck! It will pay off in the long run, and ultimately, it will have great impact upon the lives of those we serve.
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