Arm swing, let the CNS drive the show

For those arm swing/pulsers/ COM and head over foot folks consider some more research below.
Let the CNS drive the show, it is what it is there for . . . The leg motor patterns are dominant, the arms are passive and "shape" and influence the leg swing as a balance and ballast effect. As we discuss in an upcoming podcast, to cross the arms in a pumping motion across the midline of the body means one has to have compromised scapular mechanics (mostly protraction) to afford that much humeral adduction. This means we are forcing thoracic rotation as well. This means we are reversing what we know is more true, that "arm motion is driven passively by rotation of the thorax (Pontzer et al., 2009), an idea which is supported by shoulder muscle EMG data" (and not thoracic rotation by arm swing). Why would we try to create more unnatural axial spin through the spine when we are actually trying to move forward in the sagittal plane? Why would we try to force more rotation through the spine when the function of the thoracopelvic canister (ie. the core) is to stabilize rotational /angluar momentum? Hmmmm, things to ponder.

"Previous modelling studies have clearly shown that motion of the arms effectively counterbalances the angular momentum of the lower extremities during running (Hamner & Delp, 2013; Hamner et al., 2010). It has further been suggested that arm motion is driven passively by rotation of the thorax (Pontzer et al., 2009), an idea which is supported by shoulder muscle EMG data, consistent with the shoulders as spring-like linkages (Ballesteros, Buchthal, & Rosenfalck, 1965). Our data are con- sistent with this idea, showing motion of the thorax to be in the opposite direction to that of the swinging leg. Pontzer et al. (2009) also suggested that motion of the thorax is driven passively by motion of the pelvis. However, our data shows that the thorax reaches its peak angular velocity earlier than the pelvis, indicating that thorax motion is not completely passively driven by pelvic movements."

-S.J. Preece et al. / Human Movement Science 45 (2016) 110–118

Your center of mass in relation to foot strike position.

For those arm swing/pulsers/ COM and head over foot folks consider some more research below.
Let the CNS drive the show, it is what it is there for . . . The leg motor patterns are dominant, the arms are passive and "shape" and influence the leg swing as a balance and ballast effect. As we discuss in an upcoming podcast, to cross the arms in a pumping motion across the midline of the body means one has to have compromised scapular mechanics (mostly protraction) to afford that much humeral adduction. This means we are forcing thoracic rotation as well. This means we are reversing what we know is more true, that "arm motion is driven passively by rotation of the thorax (Pontzer et al., 2009), an idea which is supported by shoulder muscle EMG data" (and not thoracic rotation by arm swing). Why would we try to create more unnatural axial spin through the spine when we are actually trying to move forward in the sagittal plane? Why would we try to force more rotation through the spine when the function of the thoracopelvic canister (ie. the core) is to stabilize rotational /angluar momentum? Hmmmm, things to ponder.

"Previous modelling studies have clearly shown that motion of the arms effectively counterbalances the angular momentum of the lower extremities during running (Hamner & Delp, 2013; Hamner et al., 2010). It has further been suggested that arm motion is driven passively by rotation of the thorax (Pontzer et al., 2009), an idea which is supported by shoulder muscle EMG data, consistent with the shoulders as spring-like linkages (Ballesteros, Buchthal, & Rosenfalck, 1965). Our data are con- sistent with this idea, showing motion of the thorax to be in the opposite direction to that of the swinging leg. Pontzer et al. (2009) also suggested that motion of the thorax is driven passively by motion of the pelvis. However, our data shows that the thorax reaches its peak angular velocity earlier than the pelvis, indicating that thorax motion is not completely passively driven by pelvic movements."

-S.J. Preece et al. / Human Movement Science 45 (2016) 110–118

Coordination of leg swing, thorax rotations, and pelvis rotations during gait: The organisation of total body angular momentum

"In walking faster than 3 km/h, transverse pelvic rotation lengthens the step (“pelvic step”).
The shift in pelvis–thorax coordination from in-phase to out of phase with increasing velocity was found to depend on the pelvis beginning to move in-phase with the femur, while the thorax continued to counter rotate with respect to the femur. "

We are always trying to bring greater understanding to this group at TGG regarding gait mechanics. One must understand the implications of rotational work, and anti-rotational work on the phasic and antiphasic nature of the thorax and the pelvis. We have talked about becoming more phasic when there is spine pain. With today's study, we delve just al little deeper, particularly noting how the pelvis and the femur moving together first, before that is offset by the antiphasic nature of the thorax at higher speeds of gait.
This article uses the terms in phase and out of phase. We have learned over time that those terms to relate more so the description of how the limbs are, or are not, pairing up when a couple is walking together. None the less, the reader here should understand how they are referring to out of phase as antiphasic.

http://www.sciencedirect.com/…/article/pii/S096663620700135X

 

Which sports burn the most calories?

Photo: Gallo Images/iStockphoto  

Look at this photo. Do you see it ? How much posterior rotation (left rotation) is being driven through that left shoulder/torso rotation. That is nuts! We have a hard time believing that is not a compensation. We would be assessing for stability and mobility issues elsewhere. Heck, the elbow practically crosses the spine posteriorly ! Sheesh ! When you cannot put the movement where it should be, or control it (stabilize) where it should be controlled, sometimes you try to get it or put it elsewhere. We would love to see this lady run, we bet there is a host of clean gait problems down below. We would bet some cross over gait is present as well, after all, that left arm swing is largely predicated off of the right leg swing. Arm swing is far less independent than people think, we have written about that here on our blog numerous times. Just search “arm swing” over on our Tumblr blog.

Remember this, and if you need to go back to read about phasic and anti-phasic gaits head over and search our blog, but the amount of shoulder “girdle” (essentially thoracic rotation) is typically met by the same amount of pelvis rotation. These should be symmetrical. And, when they are not, we can drive it through various means, even as in this case, through more arm swing unilaterally. We wish we could see some axial photos from above to see how much pelvis rotation is noted  here.

Just some brief thoughts from Dr. Allen

Photo link attributed to owner: http://africanspotlight.com/wp-content/uploads/2016/03/CdBVhTzUkAELVp6.jpg

Pronating around internal hip rotation loss.

This is a remedial principle, but it is always nice to capture it on video like this. Watch this clients left foot. On initial impressions you might just say too much foot pronation, and you would be right. Some of you might say abductor-adductor twist of the foot. These are all correct. But, if we told you that this was a hip complaint client, and lack of internal hip rotation this foot action should be a simple 60Watt “light bulb moment” (translation: “epiphany”), certainly not a 100Watt moment (but for some it might be).  

This client cannot internally rotate through the hip adequately, so they have found the opposite end of the limb to internally rotate through.  They collapse through the arch/tripod, which essentially in the crudest of analogies “internally screws the limb” into the ground.  They are finding internal femur rotation through foot pronation.  Internal hip rotation is being achieved from a bottom up process if you will. Pronation through the foot complex is adduction, medial rotation and plantarflexion of the talus which will carry the tibia (and thus the femur) with it into internal rotation.  There is a problem in many clients who find that extra little bit of rotation at the hip via a foot/ankle cheat.  That problem is one of corruption of the pelvis antiphasic motion of the pelvis, they will most often dump the same hip laterally and thus drift into the frontal plane instead of achieving the antiphasic motion of the pelvis.  This will decouple the rotation of the torso in the opposite rotation of the pelvis, and thus begin the corruption of arm swing.  Want to take it another level deeper ? Ok, eat this for lunch……. asymmetrical thoracic rotation from side to side will set up. This will mean more work through scapulothoracic stabilization and cervical rotation on the side of the thoracic rotation deficit.  Still not deep enough ? Ok, evaluate their respiration symmetry.   Too many are doing respiratory work before hip rotation is clean and symmetrical, especially during gait that necessitates 1000′s of engraining steps a day.  If the hips are not clean, gait is not clean, and that means repetitive arm swing-thoracic-respiratory mechanics are not clean.

If you want to truly fix someones rooted problems, you have to be willing and able to go down the rabbit hole. 

Shawn Allen, one of the gait guys