Exploring the Links Between Human Movement, Biomechanics & Gait
Tag: flexor reflex afferent
The Cheetah man, PART 2: “Bird Dog”, again.
In last week Wednesday’s blog post (link) we discussed the video of this man running amazingly on all 4 limbs at an incredible speed. He was doing it beautifully, most people would have fallen flat on their face after the first leap forward.
As we discussed on that day, and these 2 screenshot photos will prove, there is ipsilateral interference between the foot and hand in this quadrupedal gait. This is diagonal quadrupedal locomotion (QL); the forward moving lower limb is impaired from further forward progression by the posting up (contact) hand of the same side. However, in his case, there is such quick removal of the leading hand/limb that he can advance the ipsilateral foot/leg as far forward as he is able without impediment from the same side hand contact.
As we mentioned in the Bird Dog post last week, (see photo of lady on yoga mat above) the contralateral upper limb will be in the opposite phase of the contralateral lower limb. ie when the left lower limb is in extension, the right upper limb will be in flexion (this is the classic Bird Dog position).
In last weeks blog post (see photos above), the opposite is clearly happening. One can see in the first photo that bird dog is clearly not helping to train a gait pattern, and that is ok, it has other values at times. Rather, in this first photo we see left hip extension and right shoulder extension, just as we see in the baby photo. This contradicts Bird Dog but this does support bipedal gait patterns. Think about gait. Your right leg and left arm flex until about midstance, when they start to transition into extension; the left leg and right arm are doing the opposite. At no point are the arm and opposite leg opposing one another as in Bird Dog.
As Ivo would say , “if you look at it neurologically, it is a crossed extensor reflex. It is very similar to a protective reflex called the “flexor reflex” or “flexor reflex afferent”.
The Cheetah man: A new perspective on Cross Crawl and neurologic patterning.
A few months ago we wrote a piece about Uner Tan Syndrome. Here was a key point from that blog post (blog post link) and it links beautifully to our most recent controversial blog post on the “Bird Dog” rehab exercise (link here):
[In the video presented in that blog post, and in our “Bird Dog” post photo] there is ipsilateral interference between the foot and hand in this quadrupedal gait. In this diagonal quadrupedal locomotion (QL) the forward moving lower limb is impaired from further forward progression by the posting up (contact) hand of the same side. This would not occur if the QL gait was non-diagonal (ie. unilateral), the forward progression of the lower limb would be met with same time forward progression of the upper limb, allowing a larger striding out of both limbs. This would enable faster locomotion without increasing cadence (which would be the only way of speeding up in the diagonal QL), at the possible limitation of necessitating greater unilateral truncal postural control (which is a typical problem in some of these Uner Tan Syndrome individuals who typically have profound truncal ataxia).
So, why are we showing you the video above today ? If you do not know, go read those 2 blog posts again and look more closely at the video above. At exactly 0:21 seconds into the video, at the slow motion section, you can see what we were talking about in the Bird Dog post last week, that being that the quadrupedal pattern that is neurologically substantiated is that when the right lower limb is in flexion, so is the left upper limb. (we will show these 2 photos in tomorrows post). Where as, “Bird Dog” shows the opposite, that the contralateral upper limb will be in the opposite phase of the contralateral lower limb.
Who cares right ? Well, it matters. In the video above, this could be a problem because if the right leg is in flexion that means that the right arm will be moving into extension. This means that the knee and the hand will be running into each other (look at the baby photo here). As we discussed in the Uner Tan article this will impair faster quadrupedal locomotion. It is also one of the theories as to what may have pushed us to become bipedal and allow faster ambulation (there are many theories of course). So, how then does this guy in the video move like a cheetah ? How is he going so fast with the quadrupedal pattern we have clearly outlined here ?
Within days a blog reader (Micheal L, thanks Michael) messaged us and said this:
As a person who likes what’s going on at MoveNat, this type of quadrupedal movement is referred to by them as contralateral movement and is how they teach people to crawl at their seminars. In CrossFit workouts, we also do bear crawls as an exercise, and I always try to maintain a contralateral gait. i.e. Right arm moves forward as left foot comes forwards and vice versa. So, in other words, in the Uner Tan Syndrome (UTS) the gait is cumbersome and inefficient. In the video above and at MoveNat seminars, it’s a technique/skill. Did you guys intend for this comparison, or am I out in the cornfield on this?
Here was Dr. Uner Tan himself chiming in on the dialogue:
Üner TanIt is not the same type of locomotion, i.e., not “the diagonal-sequence quadrupedal locomotion”, which is also used by non-human primates.. .
Michael: The guy runs so fast it’s hard for me to see it well. Okay, so with UTS the lower limb runs into the upper limb. In this video, his upper limb quickly gets out of the way, giving room for the lower limb (to further flex forward increasing swing phase forward step length). It’s just really hard to see it without slow motion. Thank you for clarifying.
As we said in last weeks post on all of this:
“Think about gait. Your right leg and left arm flex until about midstance, when they start to extend; the left leg and right arm are doing the opposite. At no point are the arm and opposite leg opposing one another. If you look at it neurologically, it is a crossed extensor reflex. It is very similar to a protective reflex called the “flexor reflex” or “flexor reflex afferent”.
In this video case today, it appeared on the surface because of the speed of this fella, that all that we have been talking about had been left in the dust. But, after looking at things closer and more slowly, the principles remain intact. For now.
Just a little open thinking digging today. Hope you enjoyed.