*I wrote a blog three years about the connection between the shoulder and hip during movement. It’s one of my most viewed articles. Time has marched on, I continue to study and read, and have a more full understanding of the relationship between these two body parts. Read on for an updated look at how these areas function together.
The musculoskeletal system is comprised of a variety of tissue, including muscles, ligaments, tendons, fascia and bones. The place where two bones meet, the joint, is an opportunity for force to be passed from one place to the next. The muscular tissue supports the dispersal of force up the skeleton; the ability to do this efficiently enables coordinated movement.
How well our musculoskeletal system does this simple job is predicated upon a number of factors, including strength, the degrees of freedom available at each individual joint, and how coordinated we are. Our coordination is a reflection of how often we move on a regular basis, in a variety of ways.
One of the most basic coordinated movement we perform is walking. When you walk, one of the legs swings forward, while one foot remains back, on the ground absorbing the ground reactive forces so it can be propelled forward. If the right foot is swinging forward, the left arm is swinging forward, while the right arm is back.
Think of the words that are used to describe the forward arm and leg- they are swinging, easily, using the elastic properties of the fascial system so no effort is required. It’s an amazing system, one that is taken for granted until it’s not working as well as it used to.
How well the arms and the legs swing is partially dependent on the rotation that happens at the torso and pelvis. As the right foot swings forward, the thoracic spine rotates and laterally flexes to the right. The shoulder girdle is neatly located on and around the thoracic spine- as a result, the swinging forward of the foot and the rotation at the thoracic spine allow the right arm to swing backwards.
On the left hand side of the body, the opposite is occurring. The body is moving over the left leg, so the left leg is behind the pelvis, while the left arm swings forward. All of this occurs in a very dynamic, spring-like way. It’s elastic in nature, and results in basic walking feeling almost effortless.
What happens when one side of the pelvis doesn’t move when the leg is supposed to be propelled forward? Or when the thoracic spine doesn’t rotate to one side? How does this change things?
We’ve all seen it, the walking gait that looks a little bit funny, but you aren’t sure why. How does this affect general mechanics and why does it matter?
Walking, crawling, and even throwing are movements that are based on the idea that as one leg moves forward, the opposite arm moves forward to propel something (the body, an object), through space. In fact, the large amounts of internal rotation at the humerus that occurs during the throwing motion is the fastest motion the human body produces- but it isn’t the reason an object can travel a large distance. Shoulder rotation contributes at most to 1/2 of the power produced during the throw. The rest comes from the contribution of the torso and hips. And, while other mammals can and do throw objects, none do so with as much force or power as humans. With bipedalism came rotational power.
Crawling, of course, is often the prerequisite to walking, and is consistently performed in a diagonal pattern, with the right hand and the left knee moving forward, followed by the left hand and the right knee moving forward. Think about what is required for this movement to take place. The right hand bears load through the right shoulder while the left knee bears load through the left hemi-pelvis when those two limbs are on the ground. The thoracic spine rotates a little bit to the left to accommodate the movement.
Throwing and crawling illustrate how connected the shoulder, torso, and hip are in providing stability and creating power. During the walking gait, the arms swing passively, requiring little effort. In fact, experiments that reduce or prevent arm swinging result in an increase in energy required to walk and an increase in ground reaction force, signifying a reduction in overall efficiency.
From a movement perspective, why does this matter? Because it’s a reminder that if movement is only viewed in isolation, the ability of the system to work together, like it’s designed, is being ignored.
For the arm to swing freely during, there needs to be movement at the glenohumeral joint, with subtle movement at the scapula, acromioclavicular joint, and thoracic spine. For the leg to move from providing support to swinging through the air requires movement at the rearfoot, forefoot, tibia, femur, hemipelvis, and lumbar spine. If the arm can’t move freely, or the leg can’t transition from providing support to swinging, there will be a loss of efficiency. Here is the tricky part- the loss of efficiency is occurring across a system, not across one joint.
If you work with people in any sort of setting that involves movement, whether it’s yoga, personal training, strength and conditioning, or Pilates, if you observe an arm that doesn’t swing during walking, do your eyes stop there? Or do they look further? Hopefully, they make their way to the shoulder girdle and rib cage, but what about to the pelvis and opposite hip?
For things to regain a sense of elasticity, you are probably going to need to consider how things work together. What happens at the right shoulder? What happens at the left hip? What way do the ribs like to turn? Can they rotate the opposite way?
Another question to ask yourself is do you put people into positions where rotation has to occur? And if so, where do you cue the movement from? The hip that’s moving forward? The shoulder that’s moving forward? How the hip and the shoulder move together? Or maybe you cue it from the shoulder and hip that are moving back? Or from the thoracic spine? Each option will lead to a different experience for the client, and hopefully help reinforce the way different parts of the body work together during the natural act of rotation.
The body is designed to move and attenuate forces in a variety of ways. The cross patterning that occurs during gait is one of the most fundamental movement patterns, and translates into larger force production during throwing and stability in quadrupedal positions. If you only look at what’s happening in one place, you are missing, perhaps, the most important part- how things work together.
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