Understanding what "Katy Says"
This is for my RES (TM) fellows or anyone who is interested in Restorative Exercise (TM). Sometimes it is hard to be a woman and sometimes it is hard to understand what Katy Bowman is saying.
There was recently an interesting question raised at a Restorative Exercise ™ Facebook group (not my question by the way). Restorative Exercise (TM) is a movement education course that was designed by Katy Bowman that I took last year.
My anatomical knowledge is very basic and reading the answer given by Katy Bowman did not enlighten me when I first read through it, so I thought I shall use my recently acquired skills of taking and rearranging arguments to find out the message within. I acquired this skill from a coursera course: Think again! It's all about constructing different arguments, how to deconstruct an argument, looking at different ways to reason and how to work with probabilities etc. It's going on now if you want to join.
NUMBER ONE RULE OF ARGUMENTS: Always try and make the person, who has put an argument forward, look as good as possible. You will only learn from someone else, when you interpret their argument IN THE BEST POSSIBLE WAY.
So here it goes. Considering rule number 1 but also making sure that the arguments brought forward are valid.
THE QUESTION:
How does pure sagittal plane dorsi flexion during gait (as taught in RE™) fit in with the axis of inclination of the ankle (which is oblique, triplanar and through both malleoli)?
Rephrased for non-anatomists:
How does pointing and flexing the foot straight forward during gait (as taught in RE (TM)) fit in with the axis of movement of the ankle - which is at an angle, through three planes and through both ankle bones)?
If you want to know what angle the ankle hinge/axis is at, look at your ankle joint as marked by the inner and outer ankle bones and imagine a straight line between them. The inner ankle bone is forward and higher and the outer ankle bone lower and further back.
 |
| Source (6) |
Source (6)
When I first read this question, I thought there was an issue with the feet pointing straight ahead. I thought, if the axis of movement is at an angle then the foot should be at the same angle i.e. slightly pointed outwards. But it turns out this is not the case. The foot is attached to the ankle in such a way that the ankle and foot always turn out together. No, the issue talked about is: the way the ankle is attached to the foot causes the foot to wobble slightly with every step, i.e. the inner foot lifts and lowers slightly with every step and why isn’t this considered in the way walking is described in Restorative Exercise (TM)? If you want to see the wobble in the foot talked about have a look at source (2) below, which shows a computer simulation of the ankle joint.
Here is the answer by Katy Bowman (in black), my remarks and thoughts are added in colour:
I'm hoping that you all have an A-HA moment after reading this answer. I am excited. Also, you can review the section in the Foot Book about why normal (turnout) is not necessarily natural
Reviewed info and the main points are: turn out of the foot is not natural as some studies showed, since the population being studied has been under the influence of military training and ballet, which taught them wrong alignment (heels together and feet turned out), or started to align their feet wrongly when these ideas spread to the wider population. So turn out maybe normal but not natural. Is this a valid argument? Has everyone in the study and wider population been influenced by military and ballet training? Don’t know. So will leave the argument stand as it is.
The information you've are referencing has been presented as "how the axis of inclination of the ankle is" but should have been presented as "the axis of ankle inclination of a particular group of people." It might also be more simple to write that when evaluating non-European tali, data collected shows their hinges to be more horizontal than European ankles. The talus (plural tali) is a bone that connects the back of the foot to the two shin bones: the fibula and the tibia. You can see the bony protrusion where these bones connect to the tallus, commonly described as the inner and outer ankle bone. These bony protrusion are also called malleoli. See figures above.
Katy’s reply implies that the ankle set-up on an inclination is a characteristic of European (maybe Western?) cultures and that non-Europeans have a hinge that is more horizontal, i.e. the shin bones connect to the talus more horizontally, the malleoli are of similar height and at a similar distance to the heel. Unfortunately there is no reference to check this.
Try this: Align your foot, shank and knee pit. Alignment: the foot’s outer edge is facing straight forward and the knee pit is facing straight back. If you can’t keep the ball down, don’t worry as it’s not necessary right now. You should now have your ankle's angle of inclination and it should be fairly horizontal. I can’t get my ankle bones horizontal to each other following these instructions. My outer ankle is still lower than my inner ankle. I can get them more in-line i.e. the are a similar distance from the heel if I drop the inner foot (evert the foot) or rotate the knee towards the mid-line of the body (internally rotate the knee). But I wouldn’t be able to walk like this.
Now, without moving your foot, allow your thigh and shank to relax and rotate back where it came from. If you hold a pen (or other straight object to mimic a hinge) before and after, you will see that the resulting hinge is probably at an inclined (from horizontal in three planes) angle -- the ankle mentioned in the question. My ankle inclination stays the same more or less. This demonstration does not work for me, but it’s difficult to show something in words.
One of the issues with creating a list of anatomical norms is, no one is using an objective reference system. The objective reference system I think here is the same for both sides of the arguments, i.e. the way the bones attach to the foot or how they should attach. Should they attach in the way they have been found to attach in mentioned studies/question or should the attachment points be more horizontal.
If researchers, measuring these axis used anatomical neutral in the thighs, shank and foot bones, they would come do a different conclusion. This is difficult to evaluate as the researchers or the research is not defined/referenced, so no way to check if they used anatomical neutral or not.
Instead, they are measuring how the ankle is moving relative to the ground -- not the body. So, if we measured the ankle axis on an anatomically neutral body, we would measure how the ankle is moving relative to the body. Does that make sense? Could I measure the ankle on an anatomically neutral body and measure how it moves relative to the ground? I think so.
Ideally, the ankle hinge would be relatively horizontal relative to the ground AND the body, when on a flat surface. If a hinge is horizontal it is horizontal as measured by a water level. It does not matter if you attach a body or the ground to it. Can something be relative horizontal? No. So, the argument is that ideally the ankle joint should be as horizontal as possible.
When we look at what the body does with the purpose of trying to identify and quantify "what the body is supposed to do" one's point of reference is very important. Yes, this does however not give any reason to believe the RE (TM) point of reference is the right one.
Not only is this data collected from a shoe wearing and sitting population (weak foot and lateral hip musculature), this data is analysed by a group of people who have only known artificially flat surfaces and are trying to make sense of data with respect to this context. Again, this data is not defined, so can not validate if the researcher are a shoe wearing and sitting population. Let’s assume they are. Do weak foot and lateral hip musculature stop you from collecting valid data? I don’t see a connection there. They may analyse the data in a shoe wearing context but how likely is it that they have only known artificial surfaces? Very unlikely. Also the information I found on the web (see references below) all researchers looked at the skeleton/muscle/tendon of the foot individually and how it moved as a whole as well as movement of the barefoot and used theoretically modelling to try and work out how the ankle joint is arcticulating.
While Restorative Exercise™ does use the "hinge" model, we don't discount that the subtalar joint can adjust itself in multiple planes, though we interpret this ankle motion differently than most communities. Ok, RE (TM) uses a hinge model for the ankle joint and also believes that the foot can adjust itself in multiple planes at the joint below the ankle joint i.e. subtalar joint. But this is not relevant to the question. The questioner also uses a hinge model. The question is what does the angle of the hinge cause the foot to do, does it cause it to wobble slightly with every step or not?
The current model of human study seems to have that, when there are multiple degrees of freedom of a joint, the body must require cycling through them. Meaning, walking must require not just a front-to-back motion of the ankle, but also a right to left, diagonal, etc. I don’t think this valid. For example, just because I can circumduct my hip, does not mean, that I am required to do this whenever I walk. I don’t think any human study or current model if such exists, says I should do this when I walk. Studies and the question posed suggest that you are forced to wobble slightly because of how the joint is set up - not a choice.
The body above the ankle is "fixed" and the ground is "fixed" so the ankle "must" wobble about in order to be used as it design would implicate. Again, this is not implied in the question or any studies referenced below. The questioner is not implying you should wobble with ever step but your ankle joint causes you to wobble slightly because of the anatomical features of it being at an angle.
An alternative interpretation would be, humans need to be able to maintain the stability of their entire body despite the contour of the surface. Yes but not relevant to the question. If you're hiking and step on a small mound, your foot and ankle need to adapt to prevent the pelvis (and then spine) from lurching. Meaning that relatively speaking, the body is "fixed", the ankle is "fixed" and it's the ground that is wobbling. Yes but not relevant to the question as the question never implied you would/should not be able to do this.
Said another way: We do not want a constant horizontal axis of the subtalar joint, we want a net sagittal-plane movement. The axis should be adjustable depending on what our foot is stepping on -- probably why the ankle is so deformable in the first place. If it were a hinge more like the knee, every pitch of the ground would require the body align to the surface. Not feasible for the human body trying to walk, at least before most of the planet's terrain was replaced with artificially flat surfaces. Yes, but again not relevant to the question as now we are discussing the subtalar joint, which is not the joint talked about in the question.
Because the ankle deforms kind of like a gyroscope, it is tempting to determine that the foot needs to move through all planes while walking (which is thinking like a flat-floored, shoe-wearing researcher) (this is not impied in the question, see my example of hip circumduction above) instead of concluding with a better-supported argument that the shank and everything above it should be able to move effortlessly in the sagittal plane as the ankle and foot actively deal with what the Earth's surface presents. How is this argument better supported? By what evidence, mathematical/computational modelling, anatomical studies, thought experiments? Yes we should be able to move forward (sagittal plane) effortlessly but this does not refer to the question.
CONCLUSIONS:
Right, so what have I learnt. Katy Bowman has argued that the ankle hinge being at an angle is a characteristic of a study on European populations and that non-Europeans have a more horizontal ankle joint. With a demonstration, Katy tries to show that the ankle joint can be positioned more horizontally with neutral RE (TM) alignment. This experiment did not work for me.
I came to the conclusion, that the ankle joint is determined by the way the bones are attached to each other and can’t be changed by positioning/alignment during normal gait/walking. Katy Bowman argues that the ankle joint needs to be more horizontal. Which I agree would stop the forced wobble of the forefoot when walking. The only way I can see me getting a more horizontal ankle joint is by growing same length shin bones and repositioning the bones in the foot. Not something I can do anything about as I am not considering surgery. Maybe through evolution this can change but not in my lifetime. Would be interesting to further investigate the studies on non-European ankles and why they are more horizontal.
Otherwise, I am keeping my mind open. General info on the web indicates that the forced wobble is inevitable apart from maybe Gray's (4) description of the ankle joint. I have tried to observe this wobble myself while walking and when flexing and pointing the foot in the air. I think I can see the wobble, if I point the foot in the air but am not sure I can see it when walking. (Difficult to observe though). I think like everything this issue will be dependent on the person looked at and their anthropometric dimensions (how long are their bones and how are they positioned, etc.)
What this answer by Katy Bowman does unfortunately not discuss is why the wobble of the foot in respect to the ankle is a problem. How big is it for a European/Western foot? What are the effects we try to avoid? Is there a problem or can we set the movement aside as clinically insignificant? I am thinking that if I can’t do anything about this and it doesn't have any negative side effects, there is no need to worry any further. Seems like a lot to do about nothing.
I have learnt a lot about the ankle structure though. As an insteresting bit on the side: Did you know that the ankle is a lot more stable when the foot is flexed as the bones of the foot wedge in-between the ankle bones. So if you walk with high heels with foot pointing away from the knee, the instability in your foot is not only caused by poorer balance but also by a less stable ankle structure.
So thank you again, Katy Bowman, for inspiring thought and helping me understand the body - this time the ankle joint - better.
And a trophy for you, dear reader, if you got all the way to the end of this posting. You certainly have stamina.
References: (some results of a Goggle search on ankle joint)
(1) The ankle:
(2) Ankle & Subtalar Joint Motion Function Explained Biomechanic of the Foot
(3) Joints of the ankle and foot:
(4) Henry Gray (1821 - 1865). Anatomy of the Human Body. 1918
(5) Hall, Susan (2012) Basic Biomechanics. 6th Edition. International Edition. McGraw-Hill. New York.
(6) The ankle complex:
http://www.pt.ntu.edu.tw/hmchai/Kinesiology/KINlower/Ankle.htm
Keine Kommentare:
Kommentar veröffentlichen