#phasic gait

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.

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."

*Video Gait demo: The couple in the hats, are they in phase or out of phase? Have you ever wondered why people who walk together quickly synchronize their gaits ?

The synchronization between walking partners is more complex than it seems on the surface. There are two types of synchronization, in-phase (both person’s right foot move forward at the same time) and out-of-phase synchronization (where the right foot moves forward with the partners left foot). You can see in the video above that the couple has subconsciously fallen into an Out-of-Phase synchronization.

There are multiple factors and communication mechanisms occurring. There are auditory mechanisms in play such as the sound of the other persons foot fall. There are even visual mechanisms through peripherally seeing your partners arm swing and foot fall which encourages the imitation synchronization. However, the strongest in-phase synchrony occurred in the presence of tactile feedback meaning hand holding or embracing each others waist from behind, which couples often do when walking more slowly, seem to create a stronger synchrony. When this tactile component is engaged between two walkers it is plausible that the upper and lower limbs move more freely when paired up, particularly with arm swing. Read on, there is more to it here in an post we did awhile back. . . . link below

https://thegaitguys.tumblr.com/post/29333686230/have-you-ever-wondered-why-people-who-walk

https://youtu.be/05XtMtap3Yg

Have you ever wondered why people who walk together quickly synchronize their gaits ? From healthy heart cells that synchronize to a single beat, to women in school dormitories or work places who synchronize their menstrual cycles, to fireflies who begin blinking in synchrony when they all perch in the same tree synchronization is something that is abundant in nature.  It is no wonder that we find synchronicity in one of our most primitive and frequent motor patterns, walking together with someone shows the same synchronicity phenomenon. Hold the hand of your favorite person and go for a walk. Within a few strides your gaits will synchronize. Is it because it is easier ? Is it because when synchronized the arm swings will match thus making it easier and more effortless to hold hands ?  Does the same effect occur if you are not holding hands ? Studies have concluded that although it does not happen all of the time, they found it occurs in almost 50% of the walking trials even among couples who do not usually walk together. This is far too high a percentage to not make it a statistically significant finding. The synchronization between walking partners is more complex than it seems on the surface.  There are two types of synchronization, in-phase (both person’s right foot move forward at the same time) and out-of-phase synchronization (where the right foot moves forward with the partners left foot).  You can see in the video above that the couple has subconsciously fallen into an Out-of-Phase synchronization, then after the tide splash that throws them off within just a few steps they fall right back into Out-of-Phase synchronization and hold it in that state.  There are multiple factors and communication mechanisms occurring. There are auditory mechanisms in play such as the sound of the other persons foot fall.  There are even visual mechanisms through peripherally seeing your partners arm swing and foot fall which encourages the imitation synchronization. However, the strongest in-phase synchrony occurred in the presence of tactile feedback meaning hand holding or embracing each others waist from behind, which couples often do when walking more slowly, seem to create a stronger synchrony.  When this tactile component is engaged between two walkers it is plausible that the upper and lower limbs move more freely when paired up, particularly with arm swing.

What is thought to happen is that one partner dominates the lead in the gait, just as in dancing, one person is the leader and the other is the follower. The lead partner’s lower limbs determine the movement of their arms, which in turn when holding hands, sets the arm movement pattern in the partner then determining the leg swing and stance phases. Thus, synchrony is achieved. 

However, it is important to note that many of the studies were clear to mention that even in non-tactile cases, many of the gaits of two people walking together are synchronized. This was likely due to the visual and auditory parameters however height, leg length cadence etc could also play into those successful non-tactile synchrony cases. These are interesting findings at 50% because it is very unlikely that any two people are of the same height, leg length, cadence, stride and step length.  These are all parameters that are likely to change the likelihood of gait synchrony.  Zivotofsky found that “even in the absence of visual or auditory communication, couples also frequently walked in synchrony while 180 degrees out-of-phase, likely using different feedback mechanisms”. The studies below discuss many issues of this synchrony but it is perhaps most significant in clinical rehabilitation cases or in early or moderately advanced movement impairment disorders and diseases these findings may partially explain how patients can enhance their gait function when they walk with a partner or therapist.  It is in these movement impairment syndromes and diseases where the central processing and Central Pattern Generators (CPG’s) are diseased leaving them with the need for other cues such as those discussed here today, auditory, visual and tactile.  You may have read our previous blog articles on arm swing and how intimately they are anti-phasically (opposite) paired with lower limb swing.  But today’s blog post article took limb swing to another level.  Stay tuned for more on arm and leg swing in human movement.  If you wish to read our other works on arm and leg swing and their deeper effects on gait, go to our blog www.thegaitguys.tumblr.com and enter the words “arm swing” into the SEARCH box.

Shawn and Ivo…….. taking gait far beyond what you learned about it in school. ______

References used:

J Neuroengineering Rehabil. 2007; 4: 28. The sensory feedback mechanisms enabling couples to walk synchronously. An initial investigation.  Ari Z Zivotofsky and Jeffrey M Hausdorff  Published online 2007 August 8. doi:  10.1186/1743-0003-4-28

Most folks think they know a sufficient amount about arm swing, but the truth speaks otherwise for many. Many know heaps about upper quarter biomechanics and how to assess and evaluate the joints of the upper quarter but they have no clue what to look for when it comes to the client using the limb in locomotion. What really happens during the complex arm motions during gait and various forms of locomotion in runners and throwing sports ? "For the first time, we provide evidence that the spinal interneuronal networks linking the forelimbs and hind limbs are amenable to a rehabilitation training paradigm. Identification of this phenomenon provides a strong rationale for proceeding toward preclinical studies for determining whether training paradigms involving upper arm training in concert with lower extremity training can enhance locomotor recovery after neurological damage.” -Shah et at, Brain 2013 Nov

"Our results demonstrate that altered hip rotational range of motion, measured clinically, has a direct effect on the amount of external rotation torque and horizontal adduction range of motion of the shoulder during the throwing motion." -Laundner et al, (article below)

Want to dive deeply into arm swing ? Want to really know what you are doing and missing ? Goto our blog (thegaitguys.tumblr.com) and in the search box type "arm swing". You will find nothing short of dozens of articles we have written on the topic.

The relationship between clinically measured hip rotational motion and shoulder biomechanics during the pitching motion

Kevin Laudner, Regan Wong, Takashi Onuki, Robert Lynall, Keith Meister

Dr. Allen’s Quiz question of the week. See if you can get this one.

Reference point is the Girl in the middle, big sister. Choose all that apply. Note: there is something deeper than the obvious going on here, it doesn’t make sense. Can you see it ? 

a. she (big sister) is out of phase with her little sister 

b. she is in phase with her little sister

c. she is out of phase with her little brother

d. she is in phase with her little brother

e.  A and C

f.  B and C

g. B and D

h. A and D

i. AC~DC rules

Yes, Answer  “i” is always right.

otherwise the answer is … . scroll down

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F. she is in phase with her sister to her left and out of phase with her brother (at least if you are referencing her leg swing).  With her little sister, left feet are both forward in swing at the same time.

However, there is something deeper and requires some true critical thinking. IF you got the answer correct, congratulations. IF you did not, type in “in phase gait” or “arm swing” into the blog search engine and you will be able to read more about “in phase” and “out of phase” gaits.  

Now, look at the picture again. If she is “in phase” with her little sister to the left big sister should technically have her left arm in anterior/forward swing to meet little sister’s right arm swing. But, big sister’s left foot is forward, which technically means her left arm swing should be posterior to match her normal Anti-phasic gait.  But this does not pair with little sister. Can you see that this is a conflict in synchrony ? 

In phase and phasic are not the same thing, nor are out of phase and anti-phasic. Search our blog for these differences.  

Obviously you should glean by now that “In and out of phase” gait refers to the leg swing. Whereas, phasic and anti phasic gait refers to the synchrony of the upper and lower limbs in an individual.  The lower limb spinal cord motor neuron pools are more dominant than the upper arm pools (except in climbing, which is why I spent so much time last week talking about climbing and crawling here on the blog). Thus the lower legs often run the protocols and thus why arm swing changes should not be primarily or initially coached or amended in an athlete, they are very adaptive and accommodating.  The legs need to run the show, we need our arms free to be able to carry things while walking or running (water bottle, babies, spears, rifle, brief case etc) without disrupting the normal leg swing gait mechanics.  

Big sister is “out of phase” with her brother when it comes to the legs, but their arm swings are matching in phase so that there is no conflict. When people walk “out of phase” their arm swings will always match. Thus, it would seem that this is the more harmonious way to walk with a partner. 

So how are they all walking together ? Certainly not in harmony.

Obviously the little sister is not in sync with big sister. She is much shorter, and thus her step length is going to be different and that is the likely answer. She will have to pick up cadence to keep up and that will mean much of the time she will not synchronize with her big sister. As I mentioned in a prior post on these topics, often the larger or more dominant person’s arm swing will dictate the arm swing pattern of the other partner, and this will in turn, dictate how the lower limbs synchronize to the dominant partner. It would make sense that perfect harmony would bring about “out of phase” leg swing, but it does not always occur. Why? There are many reasons I discussed here today, things like differing arm and leg lengths and step lengths come to mind.

* There is one more option, none of them are in anti-phasic gait. Maybe they all have back pain :) Back pain patients tend to shift towards phasic gait to reduce spinal torsion and shear. If they all are anti-phasic then arm and leg swing matter very little in terms of full limb swing propulsive gait. This is quite possible as well, perhaps this is just a still photo representing a very slow strolling gait and thus little need for anti phasic gaits from all 3 of them. 

Neat points if you are a true gait nerd. Did you catch it ? A picture is worth a thousand words.

Hope this little quiz helped you to put some pieces together.

One more thing, here is a clinical pearl. By walking hand in hand with someone, you can help a person learn arm swing and leg swing and how to create a clean cadence, the normal anti-phasic gait, and learn how to dual task as well as add audible, visual and tactile queues to one’s gait. It is a great tool for helping neurologic gait pathologies, post stroke gait training and helping someone who has joint replacements or back pain regain normal anti-phasic gait traits where gait has become phasic and apropulsive.