Arm swing in gait and running: Part 1.
There is so much more to it than you could ever have believed !
Here are some of the facts in NORMAL gait:
- ipsilateral arm and leg swing are in anti-phase (out of phase) meaning that in the picture above the left leg is in flexion and external rotation while the left arm is in internal rotation and extension. (You cannot tell that the left leg is in external rotation but we know that normal gait parameters dictate a lateral heel strike and external rotation.)
- contralaterally the left leg and right arm are in-phase.
- the shoulder girdle and pelvic girdle are in anti-phase as well. See the arrows overlaying the drawing. This means that, as in the picture above, as the left pelvic girdle (left hemi-pelvis) is anterior (since it moves anterior with the same side leg flexion) the left shoulder girdle is posterior. These anti-phasic motions should be equal and symmetrical bilaterally, if gait is normal.
- * so if you are paying very close attention you will note that:
- the left leg is in flexion and external rotation just like the right arm (flexion and external rotation/supination).
- thus, the right leg is in hip extension and internal rotation just like the left arm.
- This drives the oblique posterior muscular sling from right gluteus to left latissimus/lower-middle trapezius via the multi compartmentalized thoracolumbar fascia. Long ago this was coined the Back Force Transmission System. It was discussed in detail in the Second Interdisciplinary World Congress on Low Back Pain, 1995 (link) which all gait geeks have likely read a few times.
Now, many of you who are in the fields of manual and movement therapies are going to say, “guys, tell us something new and fresh, please ! This is old info going all the way back to Serge Gracovetsky’s "Spinal Engine” 1989 book.“
Yes, we know this stuff is old hat. Gracovetsky’s book was a great read, we just wish it had been longer in pages. But, did you know what these works were asking you to extrapolate from them ?
Perhaps they were reminding us of things like: Internal hip rotation is a precursor to hip extension. In other words, the hip must pass through the internal rotation phase before it starts into hip extension. This means that the opposite shoulder must do the same thing. Go ahead, get up and walk and you will note it yourself. But what you must realize is that if shoulder internal rotation range is lost or limited then the posterior sling will be insufficient and hip extension cannot be achieved as effectively. It works both ways gang ! Remember, it is not only a mechanical phenomenon, it is a centrally mediated neurological phenomenon as well. So, if you are thinking outside of the box you might realize that a frozen shoulder (adhesive capulitis) perhaps cannot be treated effectively or completely if contralateral hip extension or internal rotation are limited. They feed forward and feed backwards between each other as well; functional hip pathology can drive shoulder functional pathology. And so if you try to treat a frozen shoulder without paying attention to the gait neurologic central processing patterns then you can sometimes get the slow progress that is seen by many. Think about this the next time you look at a functional shoulder assessment pattern ! We look at the contralateral hip and gait patterns first and correlate ! Treat the person, not the symptom. And gait is part of how they move and integrate the parts.
Tomorrow we well talk more about arm swing, in "Arm Swing Part 2. "When Phase is Lost”.
Shawn and Ivo … combining almost 40 years of orthopedics, neurology, biomechanics and gait experience to get to the bottom of things … and put it into a digestible form for you. (and sharing some of this in Austin Texas today as speakers at The Running Event…. the nations largest running event.)
