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









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. 

Dr. Shawn Allen

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