Whole-body coordination patterns may become partitioned in particular ways as a function of task requirements

Just some more thoughts for those who insist on coaching arm swing changes.

"Whole-body coordination patterns may become partitioned in particular ways as a function of task requirements.”

Toddlers actively reorganize their whole body coordination to maintain walking stability while carrying an object. Hsu WH1, Miranda DL2, Chistolini TL3, Goldfield EC4. Gait Posture. 2016 Oct;50:75-81

Today we seem to be going back to dual-tasking again, in this case utilizing the arms as balance assistance devices, amongst their other functions. However, we all know that walking with a hand in a pocket, or carrying something alters our ability to maximize their ballast-like function. Balanced walking involves freely swinging the limbs in pendullar motion. Changes in arm swing will change gait economy and efficiency. We have all run with a water bottle or bag/briefcase and know how that changes the symmetry and fluidity of our gait.

Today's research piece discusses toddlers and their function as they carry objects. "children immediately begin to carry objects as soon as they can walk. One possibility for this early skill development is that whole body coordination during walking may be re-organized into loosely coupled collections of body parts, allowing children to use their arms to perform one function, while the legs perform another. Therefore, this study examines: 1) how carrying an object affects the coordination of the arms and legs during walking, and 2) if carrying an object influences stride length and width." -Hsu et al.In this study of 10 toddlers with 3-12 months of walking experience were recruited to walk barefoot while carrying or not carrying a small toy. "Stride length, width, speed, and continuous relative phase (CRP) of the hips and of the shoulders were compared between carrying conditions. While both arms and legs demonstrated destabilization and stabilization throughout the gait cycle, the arms showed a reduction in intra-subject coordination variability in response to carrying an object. Carrying an object may modify the function of the arms from swinging for balance to maintaining hold of an object. The observed period-dependent changes of the inter-limb coordination of the hips and of the shoulders also support this interpretation. Overall, these findings support the view that whole-body coordination patterns may become partitioned in particular ways as a function of task requirements." -Hsu et al.

So once again we will say it, if you are coaching the arm swing YOU want, because you do not like what you see in your client, or if you think you are helping your client get more out of their body in terms of speed, power, efficiency or anything of the sort, know that there is a higher, smarter program running the show. And that program in the client’s CNS is smarter than you when it comes to what they need for whole-body coordination pattern generation.

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

You are mostly likely not getting to your big toe at push-off if you are doing this.

You are mostly likely not getting to your big toe at push-off if you are doing this. Look at the shoe wear patterns in the photos below, they are not this runners, but another runner who also has a cross over gait. And, if you have a painful big toe, you will do it as well. Oh, and Head-over-foot related, yup. Read on . . .

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Yes, the cross over gait. Yes, when you are into a cross over gait you are most certainly head over foot. And that is most likely not a good thing.

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If you are not closer to stacking the hip over the knee, and knee over the foot (like in the photo "SUI" bib runner) you are not likely getting to much of your big toe at terminal stance loading, when you could be getting more power at push off.
Said another way, if you are attacking the ground with the feet closer together, as if you are running on a line (as in the photo) you are going to be more on the outside of the foot (note the lateral foot contact), show a similar wear/loading pattern as in these shoes, and hardly load the medial foot tripod effectively.
Go ahead, walk around your office or home right now . . . . with a very narrow step width and see how little you can load into the big toe-medial foot tripod (note how little effective glute engagement you get as well by the way. there is a reason why there is a limit to the effectiveness of a very narrow step width). Then, walk with a wider step width, note the easier more effective big toe-medial tripod loading, and, note the glutes come into play much more profoundly.
Thus, head over foot/cross over gait is foolish for effective gait. You have a big toe, don't you wish to use it ? One has to find that balance between an economical step width that still allows an effective toe off event in walking and running. A very narrow cross over-style gait does not afford us this.
So, should it be any surprise to any of us that someone with pain in the big toe or medial tripod complex will choose a narrow step width to avoid the painful loading ? No, no surprise there at all.
We have been writing about the cross over gait for 10 years, bringing little pieces of research to the forefront to prove our theories on it as the research presents itself. We first brought it to you with our 3 part video series here. Search our blog, type in "cross over gait" into the search box on the site www.thegaitguys.com and get a LARGE coffee before hand, you are going to be reading for several hours.

https://www.youtube.com/watch?v=LG-xLi2m5Rc
https://www.youtube.com/watch?v=WptxNrj2gCo
https://www.youtube.com/watch?v=oJ6ewQ8YUA

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Unique adaptations to arm swing challenges: the one armed runner. Welcome to Luke Ericson, an amazing athlete, and man

Luke Ericson is tough as nails.

Human gait is cyclical. For the most part, when one limb is engaged on the ground (stance phase), the other is in swing phase. Before I continue, you should recall that there is a brief double limb support phase in walking gait, that which is absent in running gait. Also, I wish to remind you of our time hammered principle that when the foot is on the ground the glutes are heavily in charge, and when the foot is in the air, the abdominals are heavily in charge.  

For one to move cleanly and efficiently one would assume that the best way to do that would be to ensure that the lower 2 limbs are capable of doing the exact same things, with the same timing, same skill, same endurance and same strength. This goes for the upper 2 limbs as well, and then of course the synchronizing of the 4 in a cohesive effort. For this clean seamless motor function to occur, one must assume that there would be no injuries that had left a remnant mark on one limb thus encouraging a necessary compensation pattern in that limb (and one that would then have to be negotiated with the opposite limb as well as the contralateral upper or lower limb).  

Removing a considerable mass of tissue anywhere in the body is going to change the symmetry of the body and require compensations. One can clearly see the effects of this on this athletes body in the video above. He even eludes to the fact that he has a scoliosis, no surprise there.  There is such an unequal mass distribution that there is little way the spine had any chance to remain straight.  Not only is this going to change symmetry from a static postural perspective (bulk, weight, fascial plane changes, strength etc) but it will change dynamic postural control, mobility and stability as well as dynamic spinal kinematics.  I have talked about this previously in a blog piece I wrote on post-mastectomy clients display changes in spatiotemporal gait parameter such as step length and gait velocity.

-mastectomy post: http://tmblr.co/ZrRYjx1XB8RhO

If you have been with The Gait Guys for awhile you will know that impairing an arm swing will show altered biomechanics in the opposite lower limb (and furthermore, if you alter one lower limb, you begin a process of altering the biomechanical function and rhythmicity of the opposite leg as well.) You can search the blog for “arm swing part 1 and part 2″ for those dialogues.

Arm swing impairment is a real issue and it is one that is typically far overlooked and misrepresented. The intrinsic effects of altering the body through subtraction of tissue are not all that dissimilar to extrinsic changes into the system from things like  walking with a handbag/briefcase, walking with a shoulder bag, walking and running with an ipod or water bottle in one hand. And do not forget other intrinsic problems that affect spinal symmetry, for example consider the changes on the system from scoliosis as in this case.  It can cycle back on its own feedback loop into the system, either consciously or unconsciously altering arm swing and thus global body kinematics.  

There is a reason that in our practices we often assess and treat contralateral upper and lower limbs as well as to address remnants from old injuries whether they are symptomatic or not. It all comes together for the organism as a concerted effort in optimal locomotion.

Here on TGG, and in dialogues with Ivo on our podcast, I have long talked about phasic and anti-phasic motions of the arms and shoulder-pelvic blocks during gait and locomotion/sport activity.  I have written several times about the effects of spine pain and how spine pain clients reduce the anti-phasic rotational (axial) nature of the shoulder girdle and pelvic girdle. In the video above, you can see anything but anti-phasic gait, to be clear, this is a classic representation of a phasic gait. The shoulder block and the pelvic block show little if any counter rotation, they are linked together which is not normal gait. Furthermore, if you look carefully, the timing of the right arm swing is variable and cyclically changing in its timing with the left leg. Look carefully, you will see the cyclical success and failure at the beginning of the video.  This is pathologic gait, he must be constantly fighting frontal plane sway because there is no axial anti-phasic motion. He is also constantly fighting the unidirectional rotation that the absence of an entire limb and limb girdle is presenting, you can see him struggle with this if you have looked at enough gait samplings. There is essentially frozen torso movements.  Want to see more of our work on arm swing ? search the gait guys blog.

There is so much more here to discuss, so I will likely return to this video another time to delve into those other things on my mind. Luke is an amazing athlete, he gets much respect from me.

I hope this dialogue helps you to get a deeper grip on gait and gait problems. I have written many articles on the topics of arm swing, phasic and anti-phasic gait, central pattern generators. The are all archived here on the blog. I try to write a new original thought-process article each week for the blog amongst the other “aggregator” type stuff we share from other folks social media. My weekly article serves to go deeper into things, sometimes they are well referenced and in this case, I am basing today’s discussion on the referenced work in the other pieces I have written on arm swing, phasic and anti-phasic gait, central pattern generators etc. So please do your readings there before we begin debate or dialogue, which i always welcome !

Dr. Shawn Allen, the other gait guy

Where do you want to load your foot in relation to your center of mass ?

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Who do you want to be ? The guy loading his head over his foot
(narrow step width), or the gal loading the head and COM inside the foot (less narrow step width) ?
It is not hard to guess who is gonna be faster and more powerful from these photos. The lady is stacking the knee over the foot, the hip over the knee and stabilizing the hip and pelvis sufficiently and durably to keep the pelvis level for the next powerful loading step, and the other is flexion collapsing into the stance phase knee, insufficiently loading the hip and thus dropping the opposite side pelvis. He is not stacking the joints, there is a pending cross over (look at the swing leg knee approaching midline with barely any knee spacing, thus guaranteeing a cross over step or at the very least a very narrow step width.)
Sure, some one is going to say one is a distance runner and the other is a sprinter. Yes, and our point is that the sprinter is not head-over-foot, the one with all the highly suspect flaws is head over foot ! Wider step width means more glutes. Go ahead, walk around right now with a very narrow step width and see how little efficient glute contraction you get, then walk with a notably wider step width, and you will see wider means more glutes. Keep your COM moving forward, not oscillating back and forth sideways over each stance foot, that is a power leak.

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The distance runner is showing sloppy in technique. Say what you want, but one of these runners is weak and very likely at greater risk for injury, the other is strong and durable, and likely at less risk for injury.
If you ask us, but what do we know . . . .
So, again, was ask . . . . which one do you want to be ?

Arm swing, cross over, head over foot?

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Here is a Birdseye view of someone in full stride gait. The left leg and the right arm are into flexion and external rotation.
The right leg and left arm are into extension and internal rotation.
We discussed this in depth on our lecture on wednesday night.
These counter movements drive,and are driven by, the anti-phasic properties of normal gait.
Now, lets posture some thoughts with the head-over-foot mentality (which we do not subscribe to(listen to podcasts 135-136)). . . . You can see the clear relationships here of coupled motions of the limbs. Now imagine that you forced a cross over arm swing, pumping arm Swing across your body. This is shoulder/arm adduction. So what do you think is likely going to happen in the lower limb? Yes step width narrowing, i.e. crossover gate/Leg adduction. By forcing the arms to cross the midline you are strongly encouraging the legs to do the same thing. As we have discussed many times previously, the arms can shape the movement of the lower limbs even though the lower limbs run the primary patterns of which the arms are driven from. So if you want a crossover gait , which we have for years documented research showing biomechanical challenges, and something we see many injuries driven from, go ahead and coach and train your arm swing across the body.

Where do you start?

Know any coaches to say these kinds of things?
"straighten your head, pull that right arm in and pull that right knee out, and stop crossing over in your gait, widen your step width"

Yesterday I again discussed arm swing and perhaps why not to coach it out if you merely do not like how it looks in your client. I also mentioned that head tilt, torso/trunk deviations are likely compensations, but it can go both ways. One has to solve for the problem, and not coach the changes we wish to see into the client. Where do you start with a client? Their head tilt? the Right arm abduction? The medially collapsed knee? The abducting swing leg knee ? Where do you start? If you do not examine your client, understand the principles of cause and effect of aberrant human mechanics, you just might recommend an orthotic, a stability shoe, and coach "straighten your head, pull that right arm in and pull that right knee out, and stop crossing over in your gait, widen your step width". That is fine if that is what you choose to do, but i suspect i will also see you at the county fair playing "Whack a Mole". It is the same game. You'll always lose your money, and realize that game never ends, not until you solve for "X" (the cause). -Dr. Allen


Gait and Climbing: Part 1

Lucid Dreaming is the name of a rock in the Buttermilks of Bishop, California. This is no ordinary rock. It is a V15. Summiting this rock is basically only 3 moves off of 3 holds, from your fingertips. The remainder of the climb is sliced bread. If you can do the 3, you can get to the top. The problem is, only a handful of people in the world can do it. How hard can this be, after all you start sitting down.

Strength, stability, mobility, endurance, skill, experience, movement patterns … . it is all here, today, on The Gait Guys blog.

Author: Dr. Shawn Allen

There are things that other people can do in life that rattle your brain. These are tasks that these individuals make look fairly simple, but in actuality are nearly impossible to the average person. The honest fact is that many of us could do many of these things to a degree if we would dedicate a portion of our day to building the engine to perform these tasks, but the truth is that many of us would rather sit down and be entertained than get up and struggle.

Here on The Gait Guys blog, bipedal and quadrupedal gait has been discussed for over 5 years. Discussions have gone deep into the strange quadrupedal gait of Uner Tan Syndrome and have delved into the critical neurology behind CPG’s (Central Pattern Generators) which are neural networks that produce rhythmic patterned outputs. We have gone on and on about arm swing and how they are coordinated with the legs and opposite limb in a strategic fashion during walking running gaits.

Today I will look briefly at the interconnected arm and leg function in a high functioning human arguably one of the best new hot shots in climbing, Alex Megos. This year the German, as seen in this video link today, managed to summit Lucid Dreaming, a V15 in the Buttermilks of Bishop, California. Hell, you can say that this is just a big boulder, but there are not many V15s in the world like this one. Only a few of the very best in the world have even tried this rock, and you can count even fewer who have reached the summit. So, what does V15 mean to you? “virtually impossible” just about sums it up. Watch the video, this V15 starts from a “sit-start”, many folks wouldn’t even get their butts off the ground to complete the first move, that is how hard this is. Watch the video, if this does not cramp your brain, you perhaps you don’t have one.

Are there possible neurologic differences in climbers such as Megos as compared to other quadruped species? Primarily, there is suspect of an existing shift in the central pattern generators because of the extraordinary demand on pseudo-quadrupedal gait of climbing because of the demand on the upper limbs and their motorneuron pools to mobilize the organism up the mountain. We know these quadrupedal circuits exist. In 2005 Shapiro and Raichien wrote “the present work showed that human QL(quadrupedal locomotion) may spontaneously occur in humans with an unimpaired brain, probably using the ancestral locomotor networks for the diagonal sequence preserved for about the last 400 million years.”

As we all know, the interlimb coordination in climbing and crawling biomechanics shares similar features to other quadrupeds, both primate and non-primate, because of similarities in our central pattern generators (CPG’s). New research has however determined that the spaciotemportal patterns of spinal cord activity that helps to mediate and coordinate arm and leg function both centrally, and on a cord mediated level, significantly differ between the quadruped and bipedal gaits. In correlation to climbers such as Megos however, we need to keep in mind that the quadrupedal demands of a climber (vertical) vastly differ in some respects to those of a non-vertical quadrupedal gait such as in primates, in those with Uner Tan Syndrome and during our “bear crawl” challenges in our gyms. This should be obvious to the observer in the difference in quadrupedal “push-pull” that a climber uses and the center-of-mass (COM) differences. To be more specific, a climber must reduce fall risk by attempting to keep the COM within the 4 limbs while remaining close to the same surface plane as the hands and feet (mountain) while a primate, human or Uner Tan person will choose to “tent up” the pelvis and spine from the surface of contact which narrows the spreading of the 4 contact points. Naturally, this “tenting up” can be reduced, but the exercise becomes infinitely more difficult, to the point that most cannot quadrupedally ambulate more than a very short distance. I will discuss this concept in Part 2 of this series on climbing. If you study childhood development and crawling patterns, you need to be familiar with UTS (search our blog, save yourself the time), the flaws in the neurology behind the "Bird Dog” rehab pattern, and crawling mechanics … and of course, study climbers.

Some research has determined is that in quadrupeds the lower limbs displayed reduced orientation yet increased ranges of kinematic coordination in alternative patterns such as diagonal and lateral coordination. This was clearly different to the typical kinematics that are employed in upright bipedal locomotion. Furthermore, in skilled mountain climbers, these lateral and diagonal patterns are clearly more developed than in study controls largely due to repeated challenges and subsequent adaptive changes to these lateral and diagonal patterns. What this seems to suggest is that there is a different demand and tax on the CPG’s and cord mediated neuromechanics moving from bipedal to quadrupedal locomotion. There seemed to be both advantages and disadvantages to both locomotion styles. Moving towards a more upright bipedal style of locomotion shows an increase in the lower spine (sacral motor pool) activity because of the increased and different demands on the musculature however at the potential cost to losing some of the skills and advantages of the lateral and diagonal quadrupedal skills. Naturally, different CPG reorganization is necessary moving towards bipedalism because of these different weight bearing demands on the lower limbs but also due to the change from weight bearing upper limbs to more mobile upper limbs free to not only optimize the speed of bipedalism but also to enable the function of carrying objects during locomotion.

The take home seems to suggest that gait retraining is necessary as is the development of proper early crawling and progressive quadruped locomotor patterns. Both will tax different motor pools within the spine and thus different central pattern generators (CPG). A orchestration of both seems to possibly offer the highest rewards and thus not only should crawling be a part of rehab and training but so should forward, lateral and diagonal pattern quadrupedal movements, on varying inclines for optimal benefits. Certainly I need to do more work on this topic, the research is out there, but correlating the quad and bipedal is limited. I will keep you posted. Be sure to read my 3 part series on Uner Tan Syndrome, here on The Gait Guys blog. Some of today’s blog is rehash of my older writings, naturally I am setting the stage for “Part 2″ of Climbing.

- Dr. Shawn Allen

References:

Shapiro L. J., Raichien D. A. (2005). Lateral sequence walking in infant papio cynocephalus: implications for the evolution of diagonal sequence walking in primates. Am. J. Phys. Anthropol.126, 205–213 10.1002/ajpa.20049

Scand J Med Sci Sports. 2011 Oct;21(5):688-99. Idiosyncratic control of the center of mass in expert climbers. Zampagni ML , Brigadoi S, Schena F, Tosi P, Ivanenko YP

J Neurophysiol. 2012 Jan;107(1):114-25. Features of hand-foot crawling behavior in human adults. Maclellan MJ, Ivanenko YP, Cappellini G, Sylos Labini F, Lacquaniti F.

Don't coach arm swing.

We often say that arm swing should not be coached.
Here are some of our deeper thoughts as to why we stand firm on this.

Look at this photo, there are lots of different arm swings in every group of runners. These differences are not choices for the most part, the arms are just doing what they must, based off of many parameters in a runner, things that are working right, and not so right.

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To be more clear, aberrant arm swing is often a compensation to cope with other flawed mechanics elsewhere, things such as a weak core on one side, loss of thoracic lateral bend or rotation, altered limb stability patterns, hip stability challenges etc. Thus, it is almost foolish to change an arm swing that you do not like in you or your client, because often that is not the problem. Arm swing is a power producer, but it is also a huge ballast like appendage that is used to help maintain balance changes. So, look for all possible causes of what you so, that which looked aberrant, and fix those mechanical flaws first.

From Canton: "Current research has yet to determine how passive dynamics and active neural control contribute to upper limb swing during human locomotion. The present study aimed to investigate these contributions by restricting pelvis motion during walking, thereby altering the upward energy transfer from the swinging lower limbs."

Here at The Gait Guys we have discussed for years the principles of the antiphasic nature between the pelvis "girdle" and shoulder "girdles" in that they should move in opposite rotational planes, and yet be equal in their amplitude, and that when this occurs, arm and leg swings are mostly symmetrical, equal in amplitude and symmetrical in their swing planes. This study found that when the pelvis was restricted, that the ranges of motion of the shoulder and trunk, as well as the vertical trunk center of mass movement, were also reduced, as we have said many times in our writings and in quoting the research over the years. This study also supported our long standing position that arm swing is more of a passive phenomenon, yet with complex coupling of the upper and lower limb neural networks, but also strongly taking its queues from the trunk, pelvis and leg swing.

One final thought from us, coaches, especially sprint coaches, are still going to coach arm swing and force arm swing drills, the ones they want to see, to achieve more power. . . . sigh (we get it, speed is important, but there could be a cost to making the body do what is it naturally struggling to do cleanly). So, if you are going to employ these arm swing sprint drills, get someone to fix the aberrant patterns first, if you want to see fewer injuries. Otherwise, don't be surprised if you see in your runners more thoracic lean to one side, a head tilt to one side, athletes complaining of mid or low back or neck pain, tightness, shoulder pain and the list goes on. Forcing your desired coached arm swing pattern on a clients already compensated physiology may have some unwanted costs.
-Dr. Allen (of the gait guys)

From the -Canton and MacLellan paper:
"Relating shoulder muscle activities to upper limb kinematics suggested these muscles mainly acted eccentrically, providing evidence that passive elements are a significant factor in arm swing control. However, the conserved muscle activity patterns and temporal coupling of limb movements when pelvis motion was reduced are suggestive of an underlying active maintenance of the locomotor pattern via linked upper and lower limb neural networks."

Active and passive contributions to arm swing: Implications of the restriction of pelvis motion during human locomotion.Canton S1, MacLellan MJ2. Hum Mov Sci. 2018 Feb;57:314-323. doi: 10.1016/j.humov.2017.09.009. Epub 2017 Sep 25.

Making Kim Jong-un a better sprinter. Kim Jong-un has no shoulder extension. Video proof.

Kim Jong-un has no shoulder extension. Video proof.

Perfect gait example here today, Video of Kim Jong-un's gait.
This is what aberrant arm swing looks like during someone's gait when they do not swing the arms from the glenohumeral joint, specifically not acquiring shoulder extension (posterior arm swing) . Here Jong-un is seen merely performing arm swing from flexion and extension of THE ELBOW. This is not uncommon in the obese and those without ample hip extension. Remember, the motor patterns for the arms take massive queues from the lower limb motor patterns. Without hip extension you will typically not see shoulder extension (or thoracic rotation). Do not coach arm swing, fix leg swing and stance first. -dr. allen

Making Kim Jong-un a better sprinter.

". . . .these same issues are playing out in your runners. Many do not have enough thoracic mobility or scapular stability and that is why you see their sucky arm swing (on one or both sides) that you so desperately hate and are trying to coach out of them. Or, their arm swing suck starts from somewhere deeper, down below in the core, pelvis or lower limbs. Go for the fix, and you will get the arm swing you want. Be part of your client's solution, not part of building a suckier arm swing compensation, heck, they already have one, so don't layer your desirable arm swing on top of their ever present problem."

We are pounding arm swing yet again this week. If you missed it, go back to Wednesdays post here on FB (and on our thegaitguys blog) to get caught up on those concepts, but make sure you read my post from yesterday as well.

Look at Kim Jung-un's arm swing again. As we mentioned Wednesday, there is only elbow swing, there is really very minimal if any shoulder extension swinging. But how could there be? After all, there is ZERO thoracic rotation to base this off of. Look at the video, it does not lie, his shoulders are silent, there is no thoracic rotation.
Yesterday I discussed the principles of the normal antiphasic gait, that being the pelvis and torso should rotate in equal and opposite directions (antiphasic). That requisite torso rotation helps to drive the posterior shoulder extension swing and thus the anterior shoulder flexion swing on the opposite side. Without torso/trunk rotation, the shoulders are going to be silent, and thus, arm swing must come from the elbows. This is really crappy gait mechanics.
Now, if you are going to coach him to be a sprinter (ok, lets settle for a better walker), are you going to force the arm swing you want ? or are you going to help him restore his antiphasic gait, and help him earn separation in opposite rotation between the torso/trunk and the pelvis ? If you want him to be Usain Bolt fast, help him regain antiphasic . . . give him hip and pelvis drills to help him get more hip extension (but give him the requisite core work first so he doesn't flare up his back pain) and help him get better pelvis obliquity, of which much has to come from better abdominal engagement. And then give him some thoracic/truck rotation drills to earn more of that. Then help him combine these parts. But, don't just teach him how to pump his arms as one does in sprint drills.
My point in this over exaggerated case is this, these same issues are playing out in your runners. Many do not have enough thoracic mobility or scapular stability and that is why you see their sucky arm swing (on one or both sides) that you so desperately hate and are trying to coach out of them. Or, their arm swing suck starts from somewhere deeper, down below in the core, pelvis or lower limbs. Go for the fix, and you will get the arm swing you want. Be part of your client's solution, not part of building a suckier arm swing compensation, heck, they already have one, so don't layer your desirable arm swing on top of their ever present problem. -Dr. Allen

https://youtu.be/7BRuCYcXKJs

Changing step width alters lower extremity biomechanics during running.

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The Cross over gait. We have been talking about this for years, our theories have been supported by the available research and years of patient care.
Here is another study that goes with our ideas, which gives it deeper clinical relevance.

Changing step width alters lower extremity biomechanics during running. Brindle RA1, Milner CE, Zhang S, Fitzhugh EC. Gait Posture. 2014

"Step width is a spatiotemporal parameter that may influence lower extremity biomechanics at the hip and knee joint. Peak hip adduction and rearfoot eversion angles decreased as step width increased from narrow to wide."
Step width influences lower extremity biomechanics in healthy runners. "When step width increased from narrow to wide, peak values of frontal plane variables decreased.

The Fredericson paper (Hip Abductor weakness in distance runners with iliotibial band syndrome) is also supportive. That paper found that increasing step width reduced the strain on the iliotibial band during running. Greater ITB strain and strain rate were found in the narrower step width condition.

We have said it, and will say it again, because someone will post here, "maybe, but all the pros when you watch then and see photos of them, they all have a very narrow step width, basically qualifying for what you guys call a Cross Over gait. So how can you make such bold statements?"
Our response would be, "every attempt at squeezing out more economy in ones gait, walking that fine line of riskier gait mechanics, is a game of playing ECONOMY vs. LIABILITY. And if you have built enough durability and conditioning into your system that you can nudge right up to that fence of RISK, you can play with those liabilities and squeeze out the economy of your gait (like the pros) with that narrower step width. Just be aware and careful, that when you are losing control, as the runs lengthen, that the LIABILITIES are increasing and thus so is the RISK for injury. Just remember, you are likely not a pro, and have not spend the time building a safe zone of durability on your system to endure narrow step width for 26 miles.

A good runner will train the frontal and rotational planes regularly as they engage in their sagittal sport of running. So that as fatigue sets in and the step width begins to narrow, they have some durability of the lower limb to sustain the risky mechanics of the narrow step width. There is a limit for everyone, when the well goes dry.

Whole-body coordination patterns may become partitioned in particular ways as a function of task requirements

Screen Shot 2018-12-01 at 11.06.21 AM.png


Toddlers actively reorganize their whole body coordination to maintain walking stability while carrying an object. Hsu WH1, Miranda DL2, Chistolini TL3, Goldfield EC4. Gait Posture. 2016 Oct;50:75-81


Today we seem to be going back to dual-tasking again, in this case utilizing the arms as balance assistance devices, amongst their other functions. However, we all know that walking with a hand in a pocket, or carrying something alters our ability to maximize their ballast-like function. Balanced walking involves freely swinging the limbs in pendullar motion. Changes in arm swing will change gait economy and efficiency. We have all run with a water bottle or bag/briefcase and know how that changes the symmetry and fluidity of our gait.

"Whole-body coordination patterns may become partitioned in particular ways as a function of task requirements.”

Today's research piece discusses toddlers and their function as they carry objects.
"children immediately begin to carry objects as soon as they can walk. One possibility for this early skill development is that whole body coordination during walking may be re-organized into loosely coupled collections of body parts, allowing children to use their arms to perform one function, while the legs perform another. Therefore, this study examines: 1) how carrying an object affects the coordination of the arms and legs during walking, and 2) if carrying an object influences stride length and width." -Hsu et al.
In this study of 10 toddlers with 3-12 months of walking experience were recruited to walk barefoot while carrying or not carrying a small toy.

"Stride length, width, speed, and continuous relative phase (CRP) of the hips and of the shoulders were compared between carrying conditions. While both arms and legs demonstrated destabilization and stabilization throughout the gait cycle, the arms showed a reduction in intra-subject coordination variability in response to carrying an object. Carrying an object may modify the function of the arms from swinging for balance to maintaining hold of an object. The observed period-dependent changes of the inter-limb coordination of the hips and of the shoulders also support this interpretation. Overall, these findings support the view that whole-body coordination patterns may become partitioned in particular ways as a function of task requirements." -Hsu et al.

So once again we will say it, if you are coaching the arm swing YOU want, because you do not like what you see in your client, or if you think you are helping your client get more out of their body in terms of speed, power, efficiency or anything of the sort, know that there is a higher, smarter program running the show. And that program in the client’s CNS is smarter than you when it comes to what they need for whole-body coordination pattern generation.

photo credit: courtesy of Pixabay

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

Podcast Shorts # 137.1 Arm Swing in Sport

This is a small clip on arm swing from podcast 137.. For the full podcast, head over to our website or iTunes or anywhere that you choose to download your podcasts.

Key words: arm swing, gait, gait analysis, thegaitguys

Links to find the podcast:

iTunes page: https://itunes.apple.com/us/podcast/the-gait-guys-podcast/id559864138?mt=2

Direct Download: http://traffic.libsyn.com/thegaitguys/pod_138.1_arm_swing_-_82718_5.18_PM.mp3

Permalink URL: http://thegaitguys.libsyn.com/podcast-shorts-1381-arm-swing-in-sport

Libsyn URL: http://directory.libsyn.com/episode/index/id/6975092


Our Websites:
www.thegaitguys.com

summitchiroandrehab.com doctorallen.co shawnallen.net

Our website is all you need to remember. Everything you want, need and wish for is right there on the site.
Interested in our stuff ? Want to buy some of our lectures or our National Shoe Fit program? Click here (thegaitguys.com or thegaitguys.tumblr.com) and you will come to our websites. In the tabs, you will find tabs for STORE, SEMINARS, BOOK etc. We also lecture every 3rd Wednesday of the month on onlineCE.com. We have an extensive catalogued library of our courses there, you can take them any time for a nominal fee (~$20).

Our podcast is on iTunes and just about every other podcast harbor site, just google "the gait guys podcast", you will find us.

Gait: A bottom up process (mostly).

"Bottom up" process of running ? Support that it is not "top down".

"These results support a passive arm swing hypothesis for upper body movement during human walking and running, in which the trunk and shoulders act primarily as elastic linkages between the pelvis, shoulder girdle and arms, the arms act as passive mass dampers which reduce torso and head rotation, and upper body movement is primarily powered by lower body movement."
"Angular acceleration of the shoulders and arm increased with torsion of the trunk and shoulder, respectively, but angular acceleration of the shoulders was not inversely related to angular acceleration of the pelvis or arm."

At The Gait Guys have been saying this for years in our writing based off of the research we have consumed that coaching changes in arm and shoulder swing and posture is not the way the system works, or the way to go with coaching running, not without possible ramifications to the athlete by overriding how the system is wired for locomotion. The arm motor patterns are neurologically driven by the lower limbs. It is a bottom up process as we have always said. The arms are largely subservient to the legs, the work as a team, the but quarterback is the pelvis and legs. Obliquity of the pelvis and the antiphasic principles hold true once again in this study. And monkeying with the shoulders and arm swing has a direct effect on the COM, and can thus impact the brains initial choice of optimal step width in any given contact period. Driving more arm movement can over ride inherently hard wired locomotion processes and that can lead to coaching compensatory patterns that should be first driven by lower limb mechanical changes, or coaching recommendations/exercises.
We have discussed that the arms are ballasts, they are there for balance, but also can assist in producing power, but should not be part of the mainstay and dominantly trained process. The process is only "top down" neurologically, meaning the brain is the CPU.

Control and function of arm swing in human walking and running.
J Exp Biol. 2009 Feb;212(Pt 4):523-34. doi: 10.1242/jeb.024927.
Pontzer H1, Holloway JH 4th, Raichlen DA, Lieberman DE.
J Exp Biol. 2009 Mar;212(Pt 6):894. Holloway, John H 3rd [corrected to Holloway, John H 4th].

In this study the authors
" investigated the control and function of arm swing in human walking and running to test the hypothesis that the arms act as passive mass dampers powered by movement of the lower body, rather than being actively driven by the shoulder muscles. We measured locomotor cost, deltoid muscle activity and kinematics in 10 healthy adult subjects while walking and running on a treadmill in three experimental conditions: control; no arms (arms folded across the chest); and arm weights (weights worn at the elbow). Decreasing and increasing the moment of inertia of the upper body in no arms and arm weights conditions, respectively, had corresponding effects on head yaw and on the phase differences between shoulder and pelvis rotation, consistent with the view of arms as mass dampers. Angular acceleration of the shoulders and arm increased with torsion of the trunk and shoulder, respectively, but angular acceleration of the shoulders was not inversely related to angular acceleration of the pelvis or arm. Restricting arm swing in no arms trials had no effect on locomotor cost. Anterior and posterior portions of the deltoid contracted simultaneously rather than firing alternately to drive the arm. These results support a passive arm swing hypothesis for upper body movement during human walking and running, in which the trunk and shoulders act primarily as elastic linkages between the pelvis, shoulder girdle and arms, the arms act as passive mass dampers which reduce torso and head rotation, and upper body movement is primarily powered by lower body movement."

Podcast 137: Running: Limitations in thoracic spine function matter

We cover many aspects of human movement on this podcast, the topics are broad ranging on today's show, but they are worthy of your time in our opinion.

direct download: http://traffic.libsyn.com/thegaitguys/pod_138f.mp3

Permalink: http://thegaitguys.libsyn.com/podcast-137-running-limitations-in-thoracic-spine-function-matter

Libsyn: http://directory.libsyn.com/episode/index/id/6866653


Key words:
arm swing, thoracic extension, scapular retraction, arch height, rear foot posting, forefoot loading, ankle dorsiflexion, ankle rocker, shoulder extension, SSEP, F-wave, EMG/NCV testing, gait ataxia
 
Here are some key quotes from today's show:


You may have the range of motion, but are you actually able to use it?
You haven't truly injured yourself, you've just lost your ability to compensate.

And we discuss a case study today, where the following paragraph is germane.

"Abnormal gait changes might be the first signs of an early slow cooking neurologic disorder. Most, not all, pathology is afferent, yet most (not all) EMG/NCV testing is geared towards the efferent pathology (motor end organ disease, not sensory compromise), hence, testing can miss your client's pathology.  We discuss a classic case where the client clearly had the beginnings of a neurologic disorder on our exam (clonus and joint position sense changes and clear ataxic gait) yet the testing "that was done" showed a normal study of this client.  Much pathology is afferent, the input is the problem, so you need to consider requesting Sensory nerve action potentials, SSEP and F-wave testing, because they are difficult to elicit and good technique is paramount. Hence these extra components of the test are not done, and you need to ask for this in your testing.  "Maybe it's not there because you are not looking".  We have much more on this topic, come listen to Podcast 138 and get the full monty."

Our Websites:
www.thegaitguys.com

summitchiroandrehab.com doctorallen.co shawnallen.net

Our website is all you need to remember. Everything you want, need and wish for is right there on the site.
Interested in our stuff ? Want to buy some of our lectures or our National Shoe Fit program? Click here (thegaitguys.com or thegaitguys.tumblr.com) and you will come to our websites. In the tabs, you will find tabs for STORE, SEMINARS, BOOK etc. We also lecture every 3rd Wednesday of the month on onlineCE.com. We have an extensive catalogued library of our courses there, you can take them any time for a nominal fee (~$20).

Our podcast is on iTunes and just about every other podcast harbor site, just google "the gait guys podcast", you will find us.

Gait: When loading COM (center of mass) gets complicated.

When loading COM (center of mass) gets complicated.

Screen Shot 2018-02-04 at 3.10.44 PM.png

Wednesday night on our monthly seminar we discussed some problems with different foot types and how they might load differently compared to others, possible sources of pathology and why someone might have challenges or different strategies in loading the limb over a given foot type. This is just another reason why blanket statements like load the "head over foot" just cannot be made. The COM (center of mass) is subservient to many variables, including how the foot loads, and where its foot loading target is in the step width realm. One just cannot tell or teach everyone to load the head over the foot, it is just foolish to put everyone in that blanket category (besides, it is a category we do not believe is proper or safe). There are just too many variables (genu varum, genu valgum, tibial torsion, femoral torsion, foot types such as rear or forefoot varus or valgus or forefoot supinatus, etc.). The only article we have ever read even suggesting "head over foot", actually said, COM "outside the foot", and that was only during running initiation, the first steps, to get propulsion going, it is not the way we are to run. And over the next few weeks we will continue to write about the problems and repercussions of a COM drift over the foot.

Here was a slide from last night, this is supposedly a drawing of a neutral rearfoot-forefoot relationship, and a relatively neutral pedo mapping of a supposedly neutral foot. But think about this, just because unloaded, during your examination, the foot appears neutral does it mean it will load in that neutral manner. It appears neutral in passive ROM assessment, but under dynamic loading the game can be completely different. For example, what if the tibialis posterior is insufficient? In those cases the rear foot may not support inversion, it might actually valgus load, this can force the loading into premature and sustained pronation issues. Now mind you, if the pedo mapping is dynamic, like we teach it, you will get much of the movement (and compensation) info on the mapping, but many teach static mapping (stand on this, just stand, no walking across it).
But this all comes back to what we say in gait analysis, "what you see is often not the problem, it is the compensation". This is why one must compare one's exam to the dynamic loading challenges your assessment should include, including gait observation. This is also why one is foolish to make gait recommendation off of just what one sees in someone's gait, because you can be recommending changes to an already compensated gait. Just because you think someone will load better in a manner in which you think is better does it mean they can, are able, or capable of doing so without compensation or tissue compromise.
Caveat emptor, and more so, Caveat Venditor (buyer beware, and more so, seller beware).

Dominance of the lumbosacral girdle over the cervicothoracic is probably preserved in humans

. . . dominance of the lumbosacral girdle over the cervicothoracic is probably preserved in humans
This suggests that arm swing is, to a notable degree, subservient to leg swing.

Research thus far has strongly suggested two pieces to arm swing, a passive and an active swing component. Without muscle activity, passive swing amplitude and relative phase decrease significantly. As phase decreases, it is referred to as in-phase swing pattern of the arms. The Goudriaan et al paper referenced below concluded that "muscle activity is needed to increase arm swing amplitude and modify relative phase during human walking to obtain an out-phase movement relative to the legs."
But it is more complicated that this . . . .

Research continues to suggest that interlimb coordination is achieved at the brainstem and cortical level, which this study suggests as to why we can dual task and walk with something in our hands, carry objects and even walk and run with said objects and changes in our gait . . . . because, the program is running off a top down neurologic mediated process with predictable, economically CPGs(central pattern generator) in place.
"The coordination of arm and leg movements takes the form of an in-phase relationship between diagonal limbs [64]. The dominance of the lumbosacral girdle over the cervicothoracic is probably preserved in humans as well. For example, Sakamoto et al. [65] showed that during combined arm and leg cycling, the cadence of the arms was significantly altered when leg cycling cadence was changed. The opposite, however, was not true, i.e. the arms did not affect the leg cadence."-Preece et al.

Human Movement Science 45 (2016) 110–118
The coordinated movement of the spine and pelvis during
running
Stephen J. Preece, Duncan Mason, Christopher Bramah
School of Health Sciences, University of Salford, Salford, Manchester M6 6PU, United Kingdom

Gait Posture. 2014 Jun;40(2):321-6. doi: 10.1016/j.gaitpost.2014.04.204. Epub 2014 May 6.
Arm swing in human walking: what is their drive? Goudriaan M1, Jonkers I2, van Dieen JH3, Bruijn SM4.

Arm swing and instability. To train or not to train... Should we do it?

We have long talked about arm swing and whether to change it, encourage it or just observe it. It appears to be an indicator of potential instability as well as a portent for more dire neurological problems (Alzheimers, Parkinson's)

This study looks at altered arm swing in kids with CP; how it is an indicator that there is a problem and how it can profoundly effect their gait and stability. Cerebral palsy may be an extreme case, but how does it differ REALLY (other than severity) from someone who has a mild neurological impairment, such as movement patterning disorders, that we see each and every day in our friends, family, clients and patients? Try and think out of the box and investigate the implications.

"Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability. Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing and preferred walking speed; (ii) restricted arm swing and preferred walking speed; (iii) free arm swing and high walking speed; and (iv) restricted arm swing and high walking speed. Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children. It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in children with cerebral palsy. The current results thereby partly support the suggestion that facilitating arm swing in specific situations possibly enhances safety and reduces the risk of falling in children with cerebral palsy."

Front Hum Neurosci. 2016 Jul 15;10:354. doi: 10.3389/fnhum.2016.00354. eCollection 2016.
Restricted Arm Swing Affects Gait Stability and Increased Walking Speed Alters Trunk Movements in Children with Cerebral Palsy.
Delabastita T, Desloovere K, Meyns P.

link to FREE FULL TEXT: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4945643/

Is swinging the arms worth it ? The metabolic cost of running.

The metabolic cost of human running: is swinging the arms worth it?
(precursor: *photo depicts a nice wide antiphasic gait, when that narrows, possibly for spine protection, limb swing becomes more phasic. In these senarios, forcing more arm swing action in a runner is foolish. One is not likely smarter than their client's body's protective mechanisms, so one needs to stop forcing things when they don't know what they are dealing with).

There remains scant info regarding the metabolic benefit of arm swing during human running. We have written about arm swing many times in the past, the concepts of phasic and antiphasic upper and lower limb swing (and their impact on spine loading) are critical for one to understand if they are working with runners. Without the understanding of these principles, coaching runners on form change adds risk to the plate of your client. Feel free to search our blog on these topic. But while you read on, please keep in mind all those strange unilateral compensatory arm swing things you see, such as an abducted arm on one side, a circumducting arm, one arm swinging more than the other, or less than the other, sports where we are carrying something (ie. a football) or throwing (ie javelin), or running with a water bottle. And please consider going back and re-reading all of our arm swing posts discussing why coaching a different arm swing, certainly a corrective arm swing, might be a bad idea because it could be a compensation from the lower limbs since the arms are positioned to be such good postural ballasts.

Here Arellano & Kram "compared the metabolic cost of running using normal arm swing with the metabolic cost of running while restricting the arms in three different ways: (1) holding the hands with the arms behind the back in a relaxed position (BACK), (2) holding the arms across the chest (CHEST) and (3) holding the hands on top of the head (HEAD)."

They hypothesized that "running without arm swing would demand a greater metabolic cost than running with arm swing." What the found in comparing with running using normal arm swing, a net metabolic power demand was 3, 9 and 13% greater for the BACK, CHEST and HEAD conditions, respectively (all P<0.05).

They also discovered that "when running without arm swing, subjects significantly increased the peak-to-peak amplitudes of both shoulder and pelvis rotation about the vertical axis, most likely a compensatory strategy to counterbalance the rotational angular momentum of the swinging legs."
In conclusion, Arellano and Kram's findings "support a general hypothesis that swinging the arms reduces the metabolic cost of human running". Their findings also "demonstrate that arm swing minimizes torso rotation". We infer that actively swinging the arms provides both metabolic and biomechanical benefits during human running. (Our big question is, when said clients come in for an upper quarter limb problem , is it because they may have been coached to actively swing the arms, or swing them differently?). Those who coach arm swing changes without a physical examination to determine why one arm has an aberrant swing may be driving new compensations onto old compensations, which could very well be the source of the problem.

Important: this study likely did not look at the aberrant arm swing habits that develop when there is a lower limb mechanical aberrancy. The literature has suggested that arm swing motor patterns are subservient to the leg swing motor patterns, and so coaching arm swing changes seems a bit foolish if the literature is in fact correct. Also, this study does seem to mention asymmetries in arm swing, and how these, though when different may change metabolic cost, may be necessary because of impairments in the antiphasic relationship of the upper and lower limb action.

J Exp Biol. 2014 Jul 15;217(Pt 14):2456-61. doi: 10.1242/jeb.100420.
The metabolic cost of human running: is swinging the arms worth it? Arellano CJ1, Kram R2.