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Mouck Method for Gait Analysis

Discussion in 'General Issues and Discussion Forum' started by m.mouck, Apr 27, 2009.

  1. m.mouck

    m.mouck Active Member

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    I've recently created a new method to measure human gait, and would like to apply it to recognise gait deviations due to various factors, in this case foot ailments. If a foot problem causes a person's gait to change, my method will be able to see the change, as well as track many related correlations. I don't have access to equipment, and would like to find some 3d marker data which includes the hips, knees, heels, toes, ankles, and one which is always behind the pelvis-line, like T10 or T12. Also, a measure of the inter-ASIS distance would help, though isn't absolutely required.

    If anyone can provide such data, I'm sure you'll be very impressed with the extraordinary analysis that I can provide. My method is a full movement analysis system which uses all kinematic measures. But, since I'm doing this in my spare time, it may take a while. Preferably, data with other analyses associated with it would be best, or data which is somehow unusual. Also, the data has to be an Excel compatible format and marker positions expressed in mm. I have no way to manipulate data from other programs. The CGA site of Kirtley is of little use for this, unless the data can be transformed to raw marker co-ordinates.
    Also, the kinematic measures that I use are totally new, but will form the primary kinematic measures for walking.
    I would prefer to get data from someone's own lab, so it can be discussed with you at the same time.
    Last edited: Apr 27, 2009
  2. m.mouck

    m.mouck Active Member

    Thanks for the link, Simon, but that data is of little use for me. I need the marker co-ordinates expressed in mm (or any linear measure) and have no way to transform the data myself.

    To show how this method is totally new, few people know that there are only 8 primary measurements which totally describe all of the distance and direction changes that a person can make as they walk (the 8 fundamental parameters of gait).

    This also shows that there are only 4 ways for a person to change direction as they walk, and this method measures all of them.

    If anyone has data, or would like to discuss this in detail, please post.

    I would much prefer if any data came from your own lab, though, so it can be fully discussed. This method forms the foundation of gait analysis, even though I've only recently created it, and it will take a bit of instruction to see how to use it. Once you get the hang of it, you'll wonder how this method was left undiscovered for so long.
  3. How did you manage to validate your method if it requires this kind of data and you obviously don't have access to the equipment required to generate it?

    What do you think are the eight "fundamental parameters of gait"?

    What do you think are the four methods of changing direction during walking?
  4. Mike, perhaps if you'd have posted links or attached the files you have written on “The Mouck Method for Gait Analysis here, we might have been better placed to help you.

    I found this http://www.sarbc.org/mouck.html, but the links at the bottom to what you have written don't seem to work.

    I could only find part 2 and 4 elsewhere: mouck gait&cd=3&hl=en&ct=clnk&client=safari mouck gait&cd=4&hl=en&ct=clnk&client=safari

    Could you attach all sections so that we might be better equipped to discuss this with you.
    Last edited: Apr 27, 2009
  5. Found part 5 and the forward Study&cd=1&hl=en&ct=clnk&client=safari Study&cd=2&hl=en&ct=clnk&client=safari

    Is this a complete version?

    I'm trying to track you down Mike.:D BTW, changing your initial post to say that the data from Chris Kirtley's site is of no use to you after I'd already responded to your original posting and linked you to that site is a bit rude, Mike.
    Last edited: Apr 27, 2009
  6. m.mouck

    m.mouck Active Member

    Hi Simon, I certainly didn't mean to be rude. I wasn't sure if I should add to the original comment or use a reply, I should have just used a reply. I appreciate any and all links, and greatly appreciate you taking the time to respond.

    The articles on the internet are the first ones, and I've created a large amount since then. I've tried to put in updates, but they haven't been put up. I'm waiting until the next revision before trying again.

    The 4 direction changes are shown in push-off angle (POA), foot angle (FA, not the same as the one you use), foot offset (FO) and aberrations:foot-line rotation (A:FLrot). Any change of direction when walking must show as a change in at least one of these values.

    This method doesn't need to be "validated" per se, in the same way that a ruler or protractor doesn't need to be validated. What I've really done is create a ruler/protractor for the step, which can be used to show how each relevant body segment contributes to distance and direction as a person walks. If vector properties are valid, then the system I've developed is valid.

    But, you may mean, more generally, is it consistent or repeatable (or something like that). If so, this method is consistent in the same way a ruler is consistent. Now, I'd like to use it to show that different ailments show diffferent changes to the movement patterns, but the same ailments show similar deviations in different subjects. If there's any consistency or regularity in these gait patterns, this will show in graph line variations and other measures.

    I do have 25 runs of real data, and this was used to help develop the equations, etc., even though it wasn't required, but now I hope to apply this to subjects with specific anomalies, in order to see just what's what as far as changes to gait.

    If you wish to discuss this further, it's much better if I sent you information, rather than just reading what's on the internet. It's much, much, much more than what's on there.

    But, I'm doing this in my spare time and have no resources, so the time frame is up in the air.

    If anyone is interested, I have some discussion sheets and examples, but the full article will be a little bit longer yet, since I'm in the middle of some major expansions of the material, and found it necessary to slightly alter a bit of the first stuff. If I can get e-mails, it's much better to correspond personally, but if not, it will be a month or so for the article update, and they may not even put it up very quickly on the 2 sites it's on when I get it to them, since they are very busy and these are large.

    Finally, this is all brand new. I've created many new terms and procedures, but it's all very logical and a strictly vector treatment. It will take time to see it, but this is a very significant advancement for gait analysis.
  7. Mike, while I take your point. If I invented a "new" rule or protractor which was calibrated in degrees or mm, you'd expect those calibration marks to be exact. What if the "1 degree increments" on my "new" protractor = 1.5 degrees? Have you compared to the "gold standard"? This is what I mean by validity. I appreciate that you may have devised new measures that are difficult to compare with a "gold standard" because there is nothing to compare with. But what is the ultimate objective of this gait assessment"? Is it to track individuals? If it is, how does your method compare with the current "gold standard" in tracking?

    Now you are talking reliability. The problem is that while rules and protractors may be consistent, humans are not. If we have a large sample there will be variations in the measurements of the length of a line or an angle measured using the same instrument between individuals. This is why we carry-out reliability studies on new instruments and people to report ICC's (intra-class correlation coefficients). Have you carried out any reliability studies yet? If so what were the ICC's?

    I appreciate that, but you first need to show the validity and reliability! 'Tis a worthwhile quest, but how is your system better than the ones we already have?

    I'd love to, I thought that was why you'd posted here- to discuss this. You can attach articles etc. to your posts here so we can all see and discuss your work. When you post a reply you can scroll down and hit the manage attachments button, from there you can upload files.

    Story of my life. I too have invented something new, at the moment I'm trying to work out where to apply for ethical approval to carry out the reliability studies. Then I need to work out how to generate a sample of thirty odd clinicians and a handful of subjects to carry out an inter-observer between day error experiment!!!!!!!

    In your humble opinion.:rolleyes:;)

    Mike, you strike me as enthusiastic- read my tag line. To be fair, you are clearly trying to do the science, just make sure you don't make too many assumptions and skip out some of the important bits along the way. Good luck.
    Last edited: Apr 27, 2009
  8. Mike, please define these.

    Could you also please list and define "the eight fundamental parameters of gait"?
  9. m.mouck

    m.mouck Active Member

    Hi Simon, thank you very much for your replies. I'm new to forums (as you might have suspected) and am very glad that I signed on to this one.

    I greatly appreciate your comments, and am glad to see that you are skeptical, but willing to discuss it. I once had a person stop wanting to communicate because I started to define new terms, since I wasn't "Noah Webster". It seemed quite odd to me, but oh well.

    As far as the "gold standard" comparison, I understand what you mean, but you have to appreciate that my method is what will shed light on the "gold standard", not vice versa. The material I present is the foundation, and these measures should be the primary correlations for all other areas. Ironically, if there are anomalies or problems in the "gold standard", it's appropriate to use my system to determine why.

    However, as with everything, it has to be understood exactly what each thing is showing, and not showing. It will take a while, but each element is going to have a detailed explanation. Right now some of them may be a bit thin.

    I'm sure you think I'm crazy for suggesting such a thing, but bear with me for just a minute. While I'm not a gait analyst, I used to be a scientist, and was described as very, very hard-core. And, please realize as well that absolutely no knowledge of gait was required in order to develop this method, again, crazy as that sounds. But, you do have to know vector properties, or at least the general properties of point and vector projections (which most today do, I think).

    I started this to explain why people wandered off of the path when lost (this will allow the creation of a computer program to predict the wander paths for a person lost, based only on physical characteristics, not decisions), but it grew into a general movement analysis system which can be modified to be applied to any movements, like walking, a bird flying, a person's upper body movements, quadruped, etc. The 8 fundamental parameters, etc., are from the application to biped gait.

    The general approach is to choose appropriate body points, for gait the minimum are the 2 pelvic joints and the 2 heel-points (actually the heel and toe markers are used, which are used to calculate the heel-point), project them onto the proper 2d plane (the transverse) and connect the dots, etc.

    I'm sure you see that, of course, this is exactly what is already being done using points and lines in mainly the saggital and frontal planes, with some in the transverse, as well as 3d. I'm not changing the general way things are done. I'm just reorienting it.

    It's very unfortunate that the sagittal and frontal were chosen as the main ones for analysis, though understandable. At the beginning, video data was more easily obtained in those views than the transverse, and it was natural to focus on them. And, this may be why such a fundamental layer of analysis, which my new method represents, is totally missing from a highly scientific area like gait analysis.

    You likely won't believe me right now, but it's by far the most important layer, because it provides the critical, hitherto missing, link between the footfall pattern and the 3d body, or, more fundamentally, the necessary measures which relate the positions of the feet and the pelvis. Other points provide more relationships, but the values relating the feet and pelvis are the primary ones. From here, other points, etc. can be examined.

    Why is this important is the next natural question, of course, and I could ramble on about specifics, but it may not go down too easily until you're aquainted with the general methods, which is much beyond that which is in the internet articles. One of the internet ones is the first, and I made several simplifications in order to discuss the general ideas. Since then, all simplifications are removed and considerably more done.

    Ultimately, with enough co-operation, this method provides the basis to create a computer program which can not only describe what movements aren't "normal", but provide the list of muscle variations which are the cause of the movements. This is a long way off, but now it's a matter of process, not concept.

    The majority of the work is nearly done, as far as the fundamental methodology, and I actually don't need any technical input, though, as always, I appreciate any comments, and especially if you think there are any technical/calculation errors.

    What has to be done now is application, which means the creation of tables of movement deviations which can be used as a database. I can't predict how a Parkinson's patient's gait pattern will change, I can only measure it. This, again, is exactly the same as what's being done now with other measures. The difference is the transverse values are much better (in my opinion, of course). Predictions will come when a database is created. Movement tracking is easily done now, as well.

    While marker movements and asymmentric placements between analysts isn't desired, this method can take a fair bit of that, and still provide perfectly useable data. There are limits, but this method is very, very flexible, so even partially corrupted data can be well utilized. I don't know how effectively other methods allow for that.

    As for my primary motivation, I saw glaring errors and misconceptions which I could shed light on, and, since I have the heart and soul of a scientist, I had no choice but to do what I could.

    I hadn't expected a response, since I tried on 2 other forums, and in other areas, without responses. I'm going to work up a few sheets of discussion and a couple of good figures, but it will take some time to describe all the many aspects of this system. It's applicable in literally all area of gait analysis, though it may be hard to see how, sometimes.

    Again, it's better if I give you the information, rather than the internet articles. I'm very grateful they were put up, but they're hard to update, and one has been waiting a long time. It's a whole world beyond what's shown in these, and several minor changes have been made.

    Also, I've found that for all of the misunderstandings people have had regarding this material, it's always come down to my poor explanation of something. If you disagree or don't understand something, asking very specific questions helps a great deal. I give extremely detailed answers, but I could talk for days without a focus.

    Finally, I want to try to convey the situation, as I see it here.

    I'm basically someone off the street, and you're probably never going to see this kind of thing again, so this probably seems very strange to you. "This kind of thing" is that is that an entire layer of very important, even critical, measures and analyses are totally missing from an advanced discipline like gait analysis.

    Why it happened doesn't even matter, but realize that once the importance of the relationships which are described in this method are understood, there could be a period of fairly rapid advancement in many other areas.

    Imagine having a way to show, for eg., that a variation in pressure pad data was because the person used foot offset (which has an associated lateral shift) instead of foot angle (which is a pure rotation, and is not the one which is used in current methodology), and how this change also changed the overall path characteristics by means of specific distance and direction changes. Or, to see how a person copes with an errant foot rotation, by noting the changes to the other direction parameters, as well as the linear ones.

    Walking is as much a matter of the path as it is of the body, and this method provides the details to fully investigate both elements.

    PS Does anyone know if there is a size limit to what I can post as an attachment here? I'm totally new to forums.
  10. m.mouck

    m.mouck Active Member

    Hi Simon,
    I'm going to post the definitions pages and a few diagrams showing the measures, etc. But, this may take a couple of days, since I just expanded the analysis and am in the middle of updating the definitions. I don't know if there are limits on attachments, since this is my "first day".

    I'll also collect a few key discussions, but it will likely take a good deal of interaction to adequately explain things. The technical elements, that is the measurements, etc., aren't really points for dispute, since the principles are solely based on vector geometry.

    So, there are no opinions being presented here, just a ruler protractor which uses real measures of deg and mm (or whatever). But, I've also arbitrarily defined many measures, and there may be a problem with a word or two.

    Again, thank you for your responses. I wish I had made something up to include right away. Ideally, though, if you have 3d co-ordinate data, expressed in mm and with heel-strike times, for the hips, knees, ankles, heels, toes, and one always behind the pelvis like T10, I can provide you with an analysis of that which can be discussed in detail.

    Please give me a day or two for the attachment, and I appreciate your interest.
  11. m.mouck

    m.mouck Active Member

    One more thing, Simon. Since you seem very interested, it would be easier to e-mail directly. I can send you a lot more by e-mail. I put that I wanted to be able to receive e-mails when I signed up here, but I don't know how that works .

    If you'd like some info by e-mail, let me know, and I can even send you a draft copy of parts of the updated article, as long as you realize they are drafts and will probably change.
  12. m.mouck

    m.mouck Active Member

    Hi guys,

    (I could only attach 5 files at a time, so please see the next post for the rest of the attachments.)

    Here are a few discussions and definitions for the basic system. Please keep in mind that these are draft copies, and may have spelling errors, sentence fragments, etc. I've included Fig B to show how this method can be used to show the contributions of the body positions to the stride line, for a person turning a corner.

    Fig A shows the 8 fundamental parameters, including the 4 direction parameters (although A:FLrot isn't specifically labelled), and other values for a left step.

    (To clarify how this relates to human tracking, this methodology will be used to create a computer program to help predict the wander path for a lost person. This program will describe physical movements which lead to direction changes, and will show how a person would wander due to only "physical factors". This will require an amount of data input, but populations studies, etc. will give general characteristics which may also be useful. This area will be developed as more data is obtained. Which reminds me, if anyone has 3d gait equipment and would be willing to do some runs, since the Search and Rescue (SAR=human tracking) group has no equipment, I hope you would consider doing an extra run or two for conditions relevant for that application. Any help at all would be greatly appreciated.)

    Please also keep in mind that this is a very extensive and detailed method, even though it's based on very simple principles, and it will take some time to explain all the applications. With this group, I think I'd like to go fairly quickly to the movement graphs, which will form the basis for the clinical analysis regime. I'll post a few of these in a little while.

    These graphs show movement patterns from many different perspectives, but the info will have to be boiled down a bit. In the end, a series of probably 20 or 30 of the graphs should give most of the important info. These are things which only application can determine.

    As I gain more real data, any problems in the system should become evident, but I haven't seen anything significant yet. In fact, I defy anyone in the world to show how my measures don't show what I say they do. But, some things are a bit difficult to interpret, and it may take some explanation to clarify a number of points. One thing, oddly, is to make sure you realise what a graph "isn't" showing.

    The graphs technically show the movements of points only, since all lines are derived from points. Some body segments, like the leg, are generalised to a straight line, the line between the heel-point and the pelvic joint. So, graphs which show movements of this simplified leg do not define the real leg orientation (and, it doesn't need to), but only shows the position of the foot with respect to the pelvis, the most important relationship in the leg segment.

    The knee can have many different positions, but the foot determines where a person goes.

    The real leg orientation is derived from consideration of other markers, in the leg case, the knee and ankle, with the correlation of these positions to the simplified leg-line and other body segments. This secondary correlation fully rounds out the movement analysis system.

    In this way, body segments can be generalised to simplify the primary distance and direction measures, but are readily re-correlated when desired. The vertical component is exactly the same thing. The z-component is not included usually, but can be at any time, when required. But, this doesn't exclude the vertical component, it just puts it in the proper place, or, more correctly perhaps, the more convenient place.

    There's a bit of a problem, though, since the perspective is different from what most currently use now. So, the terms to describe walking, without having to resort to the simple listing of numbers, have to be created. I've done a fair bit, but there's more to do. I usually develop terminology as I'm discussing things with others, since I'd like to have as few conflicts as possible, and the terms to be as intuitive as is practical.

    I'll get together some more discussion sheets and examples as soon as possible.

    Also, this method is dependent on marker data, and so is sensitive to specific problems like marker movements, etc., even though it can put up with a lot before there's a real problem.

    And, there are a few minor "tweaks" which I haven't done yet, but which don't affect the overall procedures. This is because any problems with using markers or calculating joint positions, etc. is totally independent of the basic methodology, and can be tackled as a separate problem.

    This means all of the equations can be developed in exactly the same way, and improvements in marker manipulation and calculations added as they are created. Even a universal world gait database can be easily updated if new calculation methods provide better results in one way or another.

    Please have a look at the figures and discussions, and I'll post more in a little while.

    Oh yes, just to let you know, I've already applied this method to several different scenarios, including forward walking, backward walking, stepping in place and during conditioning on a rotating wheel. This method is applicable in absolutely all situations, without exception, including multi-ped, assuming marker data can be obtained, of course.

    It's really a universal movement analysis system, which here is being applied to gait analysis. If anyone is studying upper body movements, like arm, this method is fully applicable there as well, we just have to come up with names of the terms which will need to be created, like I had to do with gait.

    So, with some modifications, I could use this general methodology to study the specifics of arm movements for a person who is throwing a football or a baseball. But, I can go a lot further, since I can also correlate the upper body movements with the lower in order to give a global picture which includes all body movements. For arm movements, the exact location of the shoulder joint doesn't even have to be defined, though it's better if it is.

    Like always, the more accurate the better, but a lot can still be done with a "shovel and bucket", as we used to say.

    Just one more comment about how this fits in with current methodology. This measurement system is the standard to which other things should now be compared. If there are conflicts with current methods (I don't know of any yet, except a few definitions, perhaps), using my system will uncover why there are conflicts, what they are and how things are affected.

    But, I certainly don't mean current methods should be discarded, on the contrary, current methods can now be described with respect to limitations, and will greatly augment the primary movement analysis. The very fact that these "secondary" analyses are currently used for primary diagnosis, with varying levels of success, leads me to believe that once correlated with my system these methods will provide even greater insight.

    As well, all values (force, velocity, etc.) which are calculated for points, lines and angles in the sagittal and frontal planes can also be calculated for the transverse. I haven't done this yet because, well, the movement analysis itself provides so much information that the kinetic and other measures will likely become far less important diagnostically, even unnecessary in most cases. These are things which have to be determined.

    Although this entire method is a strict vector treatment, and everything can technically be described mathematically, the system is so intuitive, once you realise what it is, that the actual equations should virtually never have to be used. The graphic representations provide pictures of all the mathematical values, and just looking at the graph line shapes and various figures should be more than enough in the vast majority of cases.

    This is one of the many major advantages of this method; complex as it is, a few pictures show all. And, mathematical errors are easily checked by plotting the original co-ordinates. All of the values are fundamentally related to only 11 real point markers, so the graphs are showing many different aspects of the same points.

    Finally, this method will always be under development, and I'm still creating some new measures. If you know of specific movements which aren't shown in any graphs (once I start showing them to you), tell me what they are and I'll create the necessary new measures to see them. There isn't a single physical movement, including vertical, which won't be seen in at least one graph, and most are seen in several. Graph manipulations also provide an extraordinary opportunity for intra-body movement correlation. Of course, here and now I'm focusing on lower body movements, but in general any movements can be correlated.

    PS Just to maintain focus. If any foot ailment changes a person's gait, this method will be able to describe and measure the exact change in walking pattern, using accurate and intuitive measurements which are only limited by the data collection (including point calculation) technique. This is assuming this person's "normal" gait pattern has already been measured. In order to define what's abnormal, there has to be a description of what's normal. That's one of the many areas of active study, the description of "normal" parameter ranges, with respect to this measurement system. For a single subject, the "standard" is a previous run. So, right now this can be applied for tracking "changes", even without knowing what's "normal".

    And, at this stage, what I'd like most is someone who can provide the required 3d marker data (for any conditions) which has other analyses associated with it, preferably using methods common to podiatry, and especially if the data is somehow unusual and current methods can't explain it. Most of my basic method is done (but, there's still a great deal to do, including 3d secondary reference grids) and now I hope to show how my system compares to what is used now, and use it to explain problem data created by other methods. Also, data for both before and after some kind of treatment would be excellent.

    Attached Files:

  13. m.mouck

    m.mouck Active Member

    Here are the rest of the attachments for the previous post.

    I won't be at the computer for a couple of days, but please have a look at the figures, etc. and the next time I post I'll put up some movement graphs for the conditioning on a rotating wheel, and a few other things.

    As far as I know, no other methods come anywhere near what I can show using these new measures.

    Thank you very much for your interest.

    Attached Files:

  14. Last edited: May 1, 2009
  15. m.mouck

    m.mouck Active Member

    Hi Simon,

    Thanks very much for the references. I can't thank you enough, since I have no resources. I'm going to look at these tomorrow.

    Here are a few figures from real data for a subject during conditioning on a rotating wheel, with the person straddling the centre, on the 2d pelvis-line grid (PLgr-2d). This grid shows the (x,y) values for points normalised to the pelvis-line (PL) in the transverse projection, so the pelvis centre (PC) is (0,0), and the right pelvic joint (RP) is on the +'ve x-axis (at about 150mm for this subject). This takes out transverse plane rotations, but not pelvic tilt.

    The PLgr-3d removes pelvic tilt as well as transverse rotations, but I'm leaving that for later on. But, measurement variations due to pelvic tilt are small, so the PLgr-2d will suffice for most applications, I think. Actually, the information in the 3d grids can be interpreted from the 2d ones. The best ones to use will be determined through use. The basic principles aren't affected by things like this.

    Also, keep in mind that this is a system, a method. Each of the graphs are a cobble in the investigative pathway, and it's through the correlation with the relevant graphs and figures that the full movement patterns are recognised.

    How many graphs are needed in a series will have to be determined through application. It could be one, or a dozen. There are several hundred unique graphs, with some being "trivial" (like the simple plotting of the x, y and z co-ordinates of the raw marker data) and some more complex (like the straddle (str) and knee straddle (Knstr) graphs), as well as "time shift", "step segment" and "correlation" overlays. (I'll post some of these in a while.)

    The PLgr-2d for the conditioning provides an extraordinary view, see Fig I. This set is for the right heel-point (RHP,ie. the right foot) during "swing", although it's actually the time period between HS's, so a short period after "start" is terminal double stance. However, the movement pattern appears to be little affected by this. Toe-off time-point could be added, if desired.

    And, keep in mind that these lines represent the movements of the whole foot, with foot-line (FL) rotations removed. FL rotations are shown on different graphs, and some figures also give very nice pictures of FL positions at HS.

    You can clearly see the maturation of movement pattern. The line shows the path the HP (foot) would make on the floor when viewed from above. As with all the graphs, the lines represent movements which can be relatively easily visualised, once you get the hang of it. Since this viewpoint is associated with the body in a "fixed" orientation, variations in this grid should be easier to associate with the relevant muscles involved, and will likely be important clinically.

    However, yes they're nice pictures, but so what. Current gait methods provide some nice pictures, too, and a few are even the same as what I use, like 3d segment rotation values (like knee angle). Here is where the current methods, as far as I've been able to find out with my limited resources, are severely limited. You have diagrams that you can't effectively interpret, since there's no way to relate the 3d body to the footprint pattern (and, hence, gait pattern), ie. you don't have the 8 fundamental parameters of gait.

    There's no way to say, for eg., that a shorter left stride-line ( = stride length in "historical" terms) is due to a decreased left step-out-line, rather than a change in one of the other 14 angles and distances which also cause changes in stride-line, and how this change has affected the direction and distance a person walks.

    Comparison of the early and late runs for the podokinetic (PK) conditioning, illustrate how movement patterns can be described, and then related to changes of distance and direction.

    The terms which I find most useful are "inside/outside, forward/backward, and closer/farther from the PL or the P," when referring to foot position in the transverse view. Please refer to Fig H for the basic quadrants with respect to the pelvis.

    To cut to the chase, the RHP start points are actually dependant on the left HS, so for this analysis the focus is just on the pattern itself, as well as the end point. This shows that for late the foot is carried more outside than for early (about 190mm from PC for early and about 240mm for late).

    This means RPA is more outside, and, since RPA-2d (not 3d) is one half of foot offset, this would result in not only a right direction change, but also a right lateral shift, if this were the only difference. There are also variations in the distance parameters, but for now I'll just focus on FO.

    LPA undergoes conditioning as well (Fig J), with the end-point approx. the same in early and late, but the left foot makes backward steps during the conditioning, so the gross movement pattern is opposite to normal for forward walking.

    The fwdblind1 and postfwd1 runs (Fig K) are before and after conditioning, resp., and both are blind runs. You can see the changes for yourself.

    Fig L shows the RPA-3d and the Rstr. The Rstr shows when the HP (foot) crosses the PL, since the value is 0 when the RHP, RP and LP are colinear, for both inside and outside. By plotting with the RPA-3d, different elements of the right foot movement are easily related.

    Next post will be a few figures with model and graph overlays.

    Mike M

    Various points:

    -one big problem with gait analysis in general is that nothing really shows the direction forward. I use the PL as the primary reference in order to have an absolute standard, but pelvis direction (Pdir) doesn't show path direction. And, the FL direction is related to the path direction, but doesn't show it itself either. Fortunately, this method doesn't depend on knowing "esoteric" gait elements, it simply shows how body orientation changes the various values, and how they're related.

    -I'll post a path figure next time, but Fig B (previous post) shows the path figure for a right turn.

    - keep in mind whether the parameter you're looking at is for a segment/point in swing or stance phases. The lines reflect the movements of different body segments, depending on whether the leg is in swing or stance.

    - I haven't bothered to put on a time point for toe-off yet, but this is easily done when desired.

    - The lines showing the pelvic joints are only approximations, since they vary a bit with pelvic tilt. The inter-ASIS distance is 300mm, so from the pelvis centre (PC) to the RP is nominally 150mm. But, the PLgr-2d doesn't take out pelvic tilt, which would make the RP value less, but over the entire run the variation is less than 1mm, so a straight line suffices, since it's really just to help visualise. All calculations use the real RP co-ordinates.

    - the Step Model (SM) is based on body points, and so can be defined at all times, regardless of body orientation. Making SM's for the intra-step period gives great views of subtle movement deviations. Unfortunately, right now I have to make the SM's manually, so it takes a bit of time.

    -one of the greatest benefits of this method is that it can accommodate the fact that each step is different, and since "errant" steps can occur at any time, it provides the opportunity to recognise the possibly errant steps. The individuality of every step is clearly seen in many ways.

    Attached Files:

  16. m.mouck

    m.mouck Active Member

    Hi guys,

    Sorry for the delay. Attached are the 2 main data tables for PK1 fwdblind1 and PK1 postfwd1 runs. Both of these are blind, and the fwdblind is before conditioning on a rotating wheel, and postfwd is after. There are more measures, but this table has the most useful ones.

    I think the best approach is to just follow the data as it's elaborated. Fig's M-O show path figures for the 2 runs. The lines are for stride-line (St) walking straddle (Wstr) and L-R-line. The Wstr is the rough equivalent of "step width" and L-R-line is the rough equiv. of "step length".

    I could make many comments, but I think it's better to leave it until the next post, which will begin to analyse and compare the 2 runs. Keep in mind that the "leg-lines", the lines connecting the pelvic joints and the heel-points, is really to help visualise. The important relationship is the foot and pelvis postions, as far as distance and direction, and the leg position is interpreted in the secondary analysis.

    The initial analysis will be path figure and Step Model overlays, in order to see the "global" aspects of the relevant body postions, as well as directly and graphically compare all of the 8 fundamental parameters. There are a number of different ways to compare each step using models.

    It may be a week or two for the next post, but please be patient.

    And, thanks again for the references, Simon. I think virtually all could benefit from correlation with this measurement system.

    And, to make another plea, I'm looking for 3d marker data, preferably with pressure pad analysis as well. If anyone can supply it, or would be willing to do a new run or two, please let me know. I think this system will be very useful in interpreting pressure pad data, and I'm anxious to apply it to that area.

    Attached Files:

  17. m.mouck

    m.mouck Active Member


    I noticed there have been no views of the main data tables in the last post. If there's a problem with the .zip file please let me know.

    While I appreciate the initial responses to the thread, I realise that this may not be what you expected.

    This method defines a movement analysis system (always under development, though ready for application now) which characterises movement patterns, with respect to gait, from several different perspectives and using many new intuitive and meaningful measurements.

    If a person walking pattern changes in any way, this method will see it. Really, what else could you ask for. If a foot ailment or anything else changes how a person walks, these measures will see it, in degrees and millimeters.

    And, although I haven't gone that far yet, this provides the opportunity to define how the relevant muscles affect the movement pattern and other gait characteristics.

    When you look at force data, what do you expect to see? You expect to see changes in the numbers depending on the specific conditions. And, you hope that the numbers can be interpreted in a way that's meaningful.

    I guess the best question is, "How's that working out so far?"

    Can you say that a rotation of the foot-line, for eg, is due to movement at the pelvic joint vs the knee joint, or the opposite pelvic joint, or opposite knee joint? Can you say exactly how much that would change the path direction, if that was the only change.

    Can current methods effectively correlate not only a variety of different body measurements, but also directly relate different conditions. There are so many advantages that this new system provides, that it would take a number of pages just to describe them.

    But, if no one is interested, I'm not going to post any more. I don't really need technical input as far as the methodology, but I do need data. What would be ideal is 3d marker data with associated pressure pad data. Either existing, or from new runs.

    Preferably, data for before and after some treatment regimen would be ideal.

    But, again, if no one is interested, this will be the last post.

    Thanks again for your interest.
  18. m.mouck

    m.mouck Active Member

    Before I begin the verbal description of the 4 global movement patterns for gait, a few comments.

    I believe that kinematic gait analysis currently doesn't have much of a place in podiatry, judging by the forum content. That's understandable, considering the very poor state of current methodology.

    But, I hope that the many limitations of previous methods won't cause you to disregard the methods which I present. None of the many problems with current methods are problems in my system (with respect to method, not data collection, which are the same, but my method tolerates a fair bit of error even in that), and, any other methods (like pressure data) can be incorporated and correlated in the analysis, if desired, since my work doesn't replace anything, but rather fills a very large gap.

    And, since there's so much material, I can only present small snippets at a time. (I've probably got about a medium to large size textbook worth of material.) I usually concentrate on the measures which I've created, but please note that the entire analysis system includes my measures, 3d measures, and any measures from other perspectives which might be useful. At the beginning, I'm also including "classical" measurements.

    My goal is not simply to promote the methods which I've developed. My goal is to find answers. For every scrap of data I get, I want to wring every possible insight out of it, and then flog it to see it there's any more. I promote my method because it's so superior to previous kinematic methods. Really, they're not even on the same planet.

    But, here's the problem. Since this is a new perspective, will I even be able to recognise when something is important? Even if I define all the movement patterns for each body segment and joint down to a fraction of a millimetre and degree, and relate the **** out of everything, there has to come a time when you say, "This pattern shows something," or, "This change in position shows this." Kinematics, of course, can't say why something happens, it just measures what happened.

    That's why I'd like to co-ordinate the development with someone(s) who's currently in each part of the industry. I can define patterns very easily. I can come up an entire system of classification and define thousands of relationships, etc., but if it's not in a form which suits each area, I might as well have been playing pool instead.

    So, I'm offering an opportunity which is available to very, very few researchers today, in any area. The opportunity to be involved in the development of analytical methodology which forms the basis, the foundation, for an entire industry (all areas which use gait analysis). Hundreds of years ago, people were doing this all the time, but few today, I think.

    But, I don't ask anyone to believe anything I say. I'm very willing to show you, using your own data from a real patient, and work with you to explore how a proper system of kinematics can enhance your professional efforts. You don't have to know anything about the method, or anything about current gait analysis. I'll explain everything from square 1.

    All it takes is one data file. Just one, and I'll show you. Either through private discussion or posts.

    I don't know what will be seen when applied to your area, but I find it hard to believe that with all of the different perspectives and relationships shown in the movement graphs, correlation graphs, data tables, line projections, figures, etc., etc., etc., that there won't be relevant details which can't be seen by other methods.

    Actually, I guarantee you that this method will see many, many details not seen in any other way, but what those details will mean to your area is something that only application and discussion will determine.

    And, please keep in mind that this method is still under development. It probably will be for the next 10 or 20 years, but it's fully applicable right now. I have a very poor computer and am having a lot of problems, so I can only develop the most central elements. The conceptual foundation is fully established, though, and further development is now just a matter of process. The details just roll out.


    Just so we're on the same page, a step is the basic unit for gait. During a step, a person manipulates the absolute and relative positions of the limb segments in order to move the body. The basic goal of the step is to move the body a distance and direction. Fortunately, it's possible to follow distance and direction through the body.

    The 8 fundamental parameters of gait (step-out-line, rear-leg-line, pelvic stretch, straddle, foot angle, foot offset, push-off angle, and aberration) show the succession of both direction and distance changes through the body which lead to the front foot being at a specific place and at a specific angle, compared to the rear foot.

    In fact, the proper vector addition of the 8 fundamental parameters will give the distance from the start-foot to the step-foot (heel-point to heel-point), as well as the relative rotation of the step-foot-line to the start-foot-line, in the horizontal plane.

    Looking at a left step, the step starts with the right foot initial contact. The right-foot-line in the overhead view is the start-foot-line, and this is the initial position reference for the step, as well as the start position for aberration measurement. The step ends with the next left foot initial contact, and the step(left)-foot-line is the final direction reference for this left step, and the first reference for the next right step.

    The 4 global movement patterns for gait are measured in the horizontal plane view. They all evolve over the entire step, and the end initial contact is the time point which defines them (although the 8 parameters and most of the other measures are continuous, and so are definable at all time points-very handy). But, there's still a certain "linearity".

    4 global movement patterns for gait

    For a left step:

    1) After initial contact of the right foot, the "first" movement pattern involves rotations and shifts of the right foot which occur while it's in contact with the floor (which is over the entire left step). These movements change the position or direction of the foot while it's planted, and so the reference frame is shifted.

    Aberration measures this using 1) foot-line rotation (A:FLrot), 2) distance of the rear heel-point to the start-heel-point (A:HPdist) and 3) angle of the heel-point shift from the start-foot-line (A:HPangl). These values relate the start-foot and the rear-foot.

    Note: At the initial contacts, the foot-line is virtually always at an angle to the floor, but this is irrelevant. The rear-foot-model is the reference for the next movement pattern.

    2) The next involves manipulating the position of the pelvis with respect to the planted right foot. At the first part of the step, the pelvis is behind the foot, and then is brought up over and passes the foot, to be extended in front at a certain angle and distance from the right foot. Push-off angle (POA) and rear-leg-line (RL) measure the result of this pattern. The rear-leg-line is the reference for the next pattern.

    3) The third involves manipulating the position of the front foot with respect to the rear foot. At the first part of the step, the step-foot (left) is behind, and is then swung forward (through the carry, then step) and extended in front, and will be placed either to the left or right of the "straight line forward" (ie. lateral rotation). This is in conjunction with a rotation of the pelvis in the horizontal plane. The result of this movement pattern is measured by pelvic stretch (PS), straddle (str), foot offset (FO) and step-out-line (SO). The step-out-line is the reference for the next pattern.

    An argument could be made that 3) is 2 patterns, with the orientation of the left pelvis with respect to the right pelvis the first, and then the orientation of the left foot with respect to the left pelvis. This may be more useful, but note that the first pattern, in and of itself, would have no effect on direction. It's involved in PS and str, pure distance elements. The second pattern, orienting the foot, is both distance and direction, measured by SO and FO.

    However, foot offset is a function of both pelvic angles. But, a deviation in the right pelvis, for eg., would be shown in the PS and str, as well as FO, with a deviation in the left pelvis would be shown in FO only, and has no effect on PS and str.

    4) The fourth involves a real or apparent rotation of the left foot-line (step-foot) in the horizontal plane. Foot angle (FA) measures this. Note: This measurement of foot angle is considerably different from what's in current use. This foot angle uses an extension of the step-out-line as the reference, and reflects both the angle and position of the foot to the pelvis-line. The step-foot-line is the start-foot-line for the next right step.

    Keep in mind that the 8 fundamental parameters of gait don't have anything to do with the leg, they relate the positions of the feet (heel-points and foot-line) and the pelvis. The knee (leg) position is analysed as a secondary element.

    I never know when to stop when explaining this material, but a couple of more points.

    This isn't a theory about gait, and the 8 fundamental parameters of gait don't define how people walk. But, the parameters can be used to create a theory because they measure how people walk.

    Also, I don't really know how important kinematic values are in podiatry, but if anyone uses the measure "base of support", or one of the other names it goes by, like step width or stride width, etc., I have information which you should read. Even with my weak resources I can see that no one currently understands this value.

    Base of support is generally related to "stability" in one or another way, I believe, suggesting that changes in base of support means changes in stability. Modelling clearly shows that base of support mainly reflects the direction changes over the step, and that the distance parameters make a contribution which is a function of the direction changes. Each element has a measurable, cumulative effect.

    Without going in to too much detail here, a change in base of support going from "wider" to "narrower" may mean a change from net inside turns to net outside turns.

    So, for a left stride, if the right step was 5deg left (inside), and the left was 5deg right (inside)(no net direction change over the stride), the base of support would be larger than if the right step was 5 deg right (outside) and the left 5 deg left (outside)(no net direction change over the stride), if foot angle was used for the direction changes.

    If anyone uses "base of support" diagnostically, please post and I'll post a full explanation, including models, of exactly how body position variations change it for each different definition of this term (I've found 4). My methodology fully explains this totally misunderstood value, very clearly (as far as how different positions affect it, how this is related to stability is a matter of interpretation).

    And, just to put a bee in your ear, if anyone uses "step length", I'd be glad to explain how this value is being interpreted improperly.

    I could say a lot more, but I'll leave it there.

    If anyone has questions, I'd be glad to further explain any element.

    I'm hoping someone can provide the 3d marker data I need so I can explore the applications to podiatry.

    One final comment, just to bring you in to my mindset. You may wonder what started this. It arose from the attempt to answer the question, "What does it mean to walk straight."

    Mike M
  19. m.mouck

    m.mouck Active Member

    Hi guys,

    I'd like to add a few comments, since I forgot to address a few of Simon's comments from earlier, regarding validity and reliability of the method. And, I'd like to say how grateful I am for all responses, especially when specific questions are defined.

    None of the comments were valid criticisms of this method, and I'd like to address each so there are no misunderstandings.

    One comment suggested that I hadn't proven the validity or reliability of the method.

    Addressing the question of validity, it lies in the validity of vector properties, and that's the only relevant comparison possible. There are no current procedures in the gait industry, in any area, which are capable of evaluating this method.

    But, if vector properties are valid, this method is valid. I think that not only are vector principles well established, but I think they can be considered exact. If vector properties are exact, then this method is exact. This is proof of the validity of the method. If you don't agree that this is true, you don't understand the nature of the material.

    There are no theories, no assumptions, no opinions, no judgements, no interpretations, no simplifications, it's all purely observation of the relationships of specific points projected onto the horizontal plane. When you do this, you see that the lines drawn between relevant points on the horizontal plane show the relationship of each 3d body segment to the whole body position, and that individual body segments contribute uniquely to the relative distance and angle between the front and rear feet. This is not an opinion, this is an observation based on the defined perspective.

    As are all the elements which I've developed in this method. The simple labelling of observations.

    There is no justification for the suggestion this method is not valid. The method is 100% valid, assuming you accept that the mathematics related to vector properties are 100% valid. Which I think most do.

    The next issue, the question of reliability, is not relevant with respect to the method itself, since it's exact. The reliability of the data collection and joint center calculations, however, are the same as with current methods.

    The more relevant question is how much data collection error could be tolerated. Will small errors in position be translated into large blips or other distortions.

    Since my method shows real positions, much more error should be able to be tolerated than when point position variations are amplified due to calculations. The specifics of this would have to be studied, but I believe the current level of accuracy and repeatability (reliability) of marker position definition is more than suitable, although exact would always be preferred, obviously.

    Another point that was raised was whether I had carried out reliability studies to report ICC's(intra-class correlations coefficients). These studies are being used in podiatry to judge worker skill and instrument operation, etc. This use, however, should be limited to only the collection of physical measurements. This technique can not be used to evaluate my methodology, or any methods or abilities which go beyond the simple measuring of segment lengths.

    For eg., if you wished to determine ICC's for a person learning how to apply 3d markers, you'd ask the person to apply the marker set to a subject, take some data, strip off the marker set, then ask the person to reapply it in the same manner, take data, then compare the segment length numbers. In this case, variations in the individual values are most likely related to variations in marker application, since the body has likely changed negligibly over a relatively short time period. This is a valid application of ICC's.

    However, consider what would happen when attempting to evaluate my method by using this technique.

    If a subject, in 2 consecutive runs, showed wildly different values for the 8 parameters, this would not mean there's a problem with the method. This would mean that the person is walking wildly different each time.

    It's not valid to interpret ICC's as measures of repeatability for anything other than simple body measurements, like segment lengths (based on marker placements), because current methods have no way of correlating the whole (lower, for now) body pattern to the position of the feet (which are the primary determinants of trajectory and orientation). That is, current methods can not provide a suitable reference.

    So, doing "reliability" studies (which are more properly labelled as repeatability studies, I think) will provide no useful information, except, perhaps, that the subject data can be added to the universal database (with permission, of course). I could, however, be misinterpreting how podiatry uses the term.

    So, no valid judgements of the method can be made using ICC's. Here, it would be at best a useless, and at worst a misleading, endeavour.

    Another question was how this new method related to the "gold standard" for tracking, this referring to the interpretation of path deviation, which is the tendency to wander from the straight path when deprived of visual cues for direction. Suffice it to say there are no standards other than personal opinion in that area. They really have nothing.

    But, to be fair, other areas have nothing as well, as far as anything capable of evaluating this method, including podiatry. My method is what will be used to evaluate all other methods, in all other areas.

    But, this method hasn't yet been applied to tracking, since this requires data. It was developed in response to a question in tracking, but the method itself is independent of that area, as it's independent of all areas.

    As for how the system is better than what you have, speaking about formal gait analysis, analytically they're not even on the same planet. This refers to kinematic measures, although kinetic measures and other areas lack the central reference also. This new method provides the means to fully characterise the walking process in terms of real mm (linear units) and degrees (angular units) for absolute and relative body movements and positions.

    But, perhaps there are "magical" numbers or procedures, privy only to those in the formal industry, which give more information than what I've seen. So far, even though current methods have many advantages which could be well used, I haven't seen anything that comes anywhere near to what I can show using my method. Again, they're not even on the same planet.

    Actually, when my method is finally incorporated into the interpretation of, for eg., force plate data, such secondary gait measurements should become much more useful, especially for relating subtleties to the 3d body position.

    Finally, I believe some may have the wrong impression about the current state of the work. I'm not "trying" to do the science, the conceptual foundation is fully established, even if I haven't explained it very well. And, there are no assumptions. Now, it's a matter of measuring as many subjects as possible in order to begin cataloguing the population variations for the relevant parameters. Although, I'd like to look at more data informally until I upgrade the computer. Crashes are a constant problem.

    So, this is the time for application, coupled with further development. I do not, however, suggest that the method be immediately applied in treatment decision making. What kind of professional would you be if you allowed that, too.

    But, that doesn't mean the data can't be analysed for real patients, since it's just numbers, so you can begin to feel comfortable with it, start to see how much info is available and how it can be used. Even if 3d data isn't regularly used in podiatry, it must be used occasionally. I believe this new method will be a valuable resource since it supplies a host of important measures and perspectives which are not available any other way, but this statement requires validation through application.

    Once you're comfortable with the data format, and see, basically, that things are as I say they are, we can tweak things to provide the maximum utility for your application, which, I believe, is diagnostics and treatment evaluation for foot ailments, and possibly orthotics and prosthetics, to which this method is also fully applicable.

    Oh yes, I don't know how many are interested, but I stated in a previous post that I started this from an attempt to answer the question, "What does it mean to walk straight."

    What would your answer be to this question? Would you like to know if I've answered it?

    I wanted to address the above issues specifically because they are valid questions for the types of procedures which you're likely used to working with. However, none of these issues are valid for this work.

    I hope no one questions the validity of this work (reliability isn't a relevant descriptor). Again, this work is 100% valid. I defy anyone in the world to show that this isn't true.

    Finally, I may not have spelled out exactly what the deal is. I developed this movement analysis method in order to describe the relationships between the 3d body segments as a person moves during walking.

    It started from a consideration of path deviation, and the effort to show why step length variation has no effect on direction. In order to do this, you have to recognise the essential physical relationships which cause the changes in direction as a person (biped) walks. And, so the 8 fundamental parameters were born.

    Once I realised the significance of the 8 fundamental parameters of gait, ie. how they provide the essential (missing) link between the 3d body and the footfall pattern, and realised that this was totally lacking in all gait areas, I recognised that this was a major breakthrough for all areas which need to understand walking patterns and their variations.

    But, the sagittal mainly, and then the frontal plane, are the foci for current gait analysis methods. This is very, very unfortunate. The sagittal and frontal are aesthetically the most pleasing, but, analytically, there's no comparison to the amount of info readily shown in the horizontal plane (keep in mind that the horizontal plane is the direct correlation of the most important elements of the sagittal and frontal planes). The horizontal plane view also gives a very good 3d perspective in many graphs, since the lower body is linked segments, and segment lengths are directly related to angle to the floor.

    At first I was hoping to present the information to members of each area so they could develop and apply it as needed. You can probably guess how that went. But, that didn't affect the method development.

    Fortunately, you don't need real data to create the equations and graphs, although developing the figures (which are actually correlation graphs) is much better with it. But, it's very useful to tweak things, and one person in the industry, to whom I'm very, very, very grateful, provided me with a very useful data set. Once you create enough equations, though, there comes a time for application.

    And that's where I am now. Begging for data. In exchange for data, I'll provide an analysis, and answer any questions you have regarding interpretation. You'll likely be very surprised about how much specific information is available. This would not be for application to a real case yet, of course, put the process has to start somewhere, and I hope it's on this forum. Archived data is fine.

    One good new run would be to find out the "error" associated with using only a sagittal view for analysis. I believe at least some podiatrists use sagittal and frontal observation as an aid. If 3d data is obtained along with a "standard" sagittal analysis, including interpretations, if there are any potential problems, analysis using my method will show it.

    And I'll see it, and, with a bit of explanation perhaps, I'm sure you'll see it too. This would be a valid application of ICC as an indicator of researcher skill in sagittal analysis, since the required reference standard is provided by my method. In fact, my method provides the required standard for all other methods (force plate, electromyography, etc).

    Also, it seems reasonable to expect that an injury affecting gait would have specific effects which can be measured; and, that the same injury at a different time would show the same effects. If this is true, my method would prove it.

    It seems reasonable to expect that 2 subjects with the same injury would show similar gait (primary) problems. If this is true, my method would prove it.

    If a person walks differently each time they take a step, my method would (and does) show it. And, shows how they differ each time, in terms of absolute and relative body positions and trajectories. Really, what more do you think has to be shown. I'm laying it all out on a silver platter, right in front of you. You just have to realise what you're seeing.

    But, there's no single graph or figure which will answer all the questions. This is a method using correlation. The initial analysis of the 8 fundamental parameters provides the essential details to describe the most important aspects of the gait pattern, the positions of the feet and the pelvis.

    Each parameter can be changed by only a certain number of factors, and, using correlation graphs, time shift and line segment overlays, secondary reference systems (like the L-R, PL, etc. grids), Step Model manipulations, path manipulations, etc., etc., etc., etc., etc., the primary kinematic cause of any gait anomaly can be tracked down. So, what can be provided are statements of absolute and relative limb positions during the entire movement cycle. It's up to each area to realise the importance of those positions and movements.

    There are no current methods (as far as I've been able to find), except mine, which shows how the body segments co-ordinate to put the foot in front (or anywhere) to take a step. Really, nothing comes anywhere near to what I provide.

    But, it could be this forum isn't the place for this. If so, I'll continue the work and thank those who have shown interest. If gait analysis is never used in podiatry, would someone please post and enlighten me.

    I value all comments. If there are any questions, I'll answer them in great detail.

    Mike M

    PS I came across a thread discussing "snake oil" salesmen, and I hope that hasn't poisoned this discussion. There are no oils, snake or otherwise, nothing for sale and no money will be exchanged. I would, of course, like to find funding for this work, considering how important it will be to so many areas of research, but I'm not naive. I am pleading for something, but it's not money, it's your understanding and co-operation.

    PPS One final question. In a recent post I described the movement patterns and positions which all bipeds must use to change the position of the body, for both distance and direction. Has this ever been done before? Does anyone dispute these patterns and measures?
  20. Mark do you live near a Uni with a Physio/Pod school or any Human Movement type course. There must be a way for you to speak to someone and get use of some equipment that you need. Then maybe write a paper for here or publish it. I have read the thread more than once at it seems to me to get more confusing as it goes. I think you need to get it all written down with a group of subjects that you are incharge of testing, maybe it will make some sense to me then.... Goodluck

    Edit: maybe it does make sense to others and it is just me. I also wrote Mark for your name sorry Mike.
  21. Agreed, I just can't see the clinical use of this- but maybe that's just me too. Mike, you don't seem to have moved forward since last April, I think Michael's advice is good, perhaps you need to contact some of the local Universities. Indeed, perhaps it's time to write your thoughts down for a peer-reviewed journal such as Gait and Posture or Clinical Biomechanics, once published this paper may act as a spring-board for you and your research. Good luck with your future.
  22. Graham

    Graham RIP

    I have to agree with Simon and w Weber. Those of us here attempt to at least observe using as far as possible validated measures and analysis techniques. Stating that the math of Vectors is enough evidence is very different from demonstrating this objectively.

    You may have something special here, I don't know, but you will disappear into the depths of "very forgetful" if you can not produce Valid and repeatable objective data. It would be a shame to have put so much thought into something and not demonstrate it's potential objectively.
  23. Rather than answering in great detail, I'd prefer if you could answer this simple question in one short paragraph: How does this improve my patients care?
  24. m.mouck

    m.mouck Active Member

    Thank you very, very much for the responses. Now I see what the problems are.

    Please let me address one comment Simon made suggesting I hadn't moved forward since April. With all due respect, it's not me that hasn't moved forward. But, I take that as a failure on my part to properly present the material.

    The fundamental development has been moving ahead as it always has. In fact, I've made 2 more significant extensions, as well as formally describing the only possible horizontal plane movement patterns and direction changes for all bipeds, which I'm fairly sure has never been done before. Also, since my work supplies the required elements for a universal gait database, I've started work on this as well. But, what good is posting more until the basic material is understood.

    I'll give your paragraph first, Simon, regarding how this improves patient care.

    How it would be relevant depends on the equipment you have available. In all cases, proper consideration of this material will not only enhance your ability to accurately diagnose ailments (if they affect gait), but will greatly aid in the determination of treatment options for gait related afflictions (using modelling, which will be a very powerful tool in diagnostics and treatment decision making), and, you'll be able to track exactly how the gait pattern has changed after any treatment (in great detail and over any length of time) in order to evaluate the efficacy. You apparently don't see it yet, but there's an extraordinary amount of critical detail in this method. This method is fully applicable to orthotics and prosthetics as well.

    If you have 3d equipment, direct application provides the benefits. Without it, you can enhance your accuracy with sagittal and frontal visual analyses (and force plate, etc.) if my method is incorporated while learning those techniques. Frankly, I wonder how you judge yourselves using those methods now, since you lack the required standard.

    Since my method provides the required standard, at least the limitations of those viewpoints can be defined and measured, and strengths fully explored and developed, if any. If you don't see how, if you provide the data I'll show you.

    Thank you for the suggestion to publish in a peer-reviewed journal. I've tried to contact several, and it's not as easy as it sounds. For you, perhaps. Really, just consider your own attitude, even after all I've said, you don't see how it's applicable clinically. It's a revolutionary advancement for clinical gait analysis. Easily more important than the introduction of 3d gait techniques or any of the other analysis methods like force plates, although 3d techniques are needed to fully utilise the horizontal plane data. This provides the central reference for all gait analysis. It just happens to be from a perspective which you're not used to using yet.

    But, even though you have no reason to trust me, it's clear to me, anyway, that gait cannot be properly understood without the consideration of the measurements which I describe.

    Thank you for the suggestions regarding obtaining data. I've tried those routes, on a number of occasions, with no response. For universities, the .edu network is filtered, but I've had e-mails forwarded through the main office, with no response.

    This didn't surprise me. And, I hope you don't think it's any reflection on the material. The material is rock solid. (The standard challenge is that I defy anyone in the world to prove that anything I've said to date isn't true. Do you disagree with, or can you challenge in some way, anything I've said so far? Please keep that in mind.). One person did respond and provided a very useful file, but I haven't obtained permission to discuss the data yet.

    But, getting more data outside your area won't help apply it to your area. If what I'm showing you doesn't click, it won't do any good to show more of the same thing. But, a file of your own is a different story. Any file is fine, from any time. Of course, not a current patient (I won't agree to apply this to a current patient yet either, I hope you don't believe I'd be that frivolous), but preferably with some condition which is commonly known across the industry, and with the original analysis included.

    This is an important element, I hope to get data where a standard analysis has also been performed. It's not required, but I think that by far the best way to begin the application to each area is to do an analysis and show how my information relates to yours, and how much more I can provide. But, I'll take anything I can get.

    Thank you for your comments Graham. Of course, I know what you mean when you say I have to produce valid and repeatable objective data, though I don't agree those are the proper terms to use, but the data needed to do that already exists, it's just a matter of applying the method to it. The data is just 3d marker data and it's sitting in files on computers everywhere.

    It makes no sense to try to provide more, not at this stage. It should be applied to archived cases so you can see how to use it. Once you're comfortable, and see the vast amount of relevant, critical data which is available, you can take over the application and decide for yourself when to start to apply it to current cases, and my role will be to continue to facilitate the application as the primary technical reference.

    And, I appreciate what you mean when you say that those of you here try to use validated measures and analysis techniques. But, I have to ask what "validated" measures are you using, and how did you validate them? I'd hazard a guess to say, from what I've seen with my limited resources, that there are very few, if any, valid measures, even if you're referring to values like cadence, stride length, step length, etc., and this includes sagittal and frontal measures of joint positions.

    The measurements and systems used for current kinematic gait analysis (from what I've seen on the internet) are terrible and few are valid (I could correct them all, though).

    You may have become used to using them, so they may be "validated" to you, but that doesn't make them valid measurements. Take stride length, for eg. Very simple measure, usually defined as the distance between the point of initial contact on one foot to the same point at the next initial contact of the same foot.

    Do you believe that "stride length" is a validated measure? It's not. The measure itself is valid, as are all simple measurements of the distance between 2 points, but the current interpretation is not valid. So, gait analysis is using a valid measurement (although it's a very poor one), which is being interpreted and used in an invalid manner.

    That is, if you interpret "stride length" as the distance travelled by the foot over the stride, which I believe most do. This is not a valid interpretation. My measure of "stride-line" is the valid measure for this value. But, there would only be very minor errors between the two in this case, since the errors in the stride length measure mostly cancel out, so the actual number recorded would be close to the accurate stride-line value.

    Do you believe "step length" is a valid measure? This one is probably the most invalid of the measures in current use. Step length is usually defined as the distance from the point of initial contact of one foot to the same point on the next initial contact of the contralateral foot. Odd that one of the few measurements which is almost universally used across all gait areas is probably the most invalid.

    That is, it's not a valid measure if you interpret step length as the distance the foot travels over the step, which I think most do. At least, that's what people are trying to show with this value. (Does anyone still believe that a person changes their step length in order to change direction? I hope not.)

    However, this definition of step length includes a component from the pelvis, and it varies differently due to foot offset than the valid measure (which is my step-line). I'm going to write a full description of "step length" in order to clarify the problems with this value, and how my method totally clears it up and defines the proper value.

    In my system, the value you call "step length" is called "L-R-line." And, its important when interpreted properly, especially for human tracking.

    One other consequence of using step length as you do, and sagittal analysis, is it distorts interpretation. For eg., you likely believe that a person rotates the pelvis anteriorly in order to increase the "effective leg length" for the step. This is one of the "6 determinants of gait" described by Saunders et al.

    But, it appears to be incorrect. I only have data for 2 different subjects right now, but if they are representative of how people normally walk, the pelvis is usually drawn back slightly, to decrease the distance of the step. (There has to be more subjects studied to validate this (since it's an interpretation of a measurement), since there are likely many variations.)

    It only appears that the pelvis is rotating forward because the sagittal view distorts the picture. A person is actually zig-zagging when they walk (everyone always turns with every step), with the body trajectory smoothed due to momentum. I can show you this with the data I currently have. If anyone is interested in the types of errors associated with sagittal analysis, please post and I'll describe some of them using real examples.

    Current gait methods have many problems with poor methodology. For eg., there are several definitions of "base of support", and each can be described by my method, but one in particular shows how the lack of a proper reference system will create nothing but problems when it comes to interpretation.

    Some use base of support as an area on the floor defined by a box around the single footprint in single stance and a polygon encompassing both prints in double stance. The COM trajectory is plotted as the shortest distance (in the horizontal plane) to the border-line of these areas. This graph is being used, I believe, to judge stability or support, or something of that nature (or whatever). Does this seem like a logical way to investigate this?

    Can anyone see the fatal flaw in this system? This is not a valid method to investigate this (or anything).

    The fatal flaw is that an interpretation has been built in to the reference system. Valid interpretation of this data is impossible.

    Consider the output from this measurement paradigm. The output is distance of a point, the COM projection, to a line which is the edge of an area defined by the position and orientation of the feet.

    In order for a method to be analytically valid, it has to be able to distinguish between conditions. For eg., let's say you have a graph which has a line shape that, by some other method, you know that everyone who has, say positive Trendelenburg sign, shows this exact line pattern.

    If you then take a person who shows this exact line pattern, but by the same other methods you've determined they don't show positive Trendelenburg sign, you can see how the graph would not be a valid way to evaluate whether a person shows this sign.

    This is exactly what you're doing when using an area on the floor which is a function of foot orientation as the reference standard.

    Consider any step. The reference area is defined by the foot orientation and the COM has a specific distance from the edge at each time point. These graphs have specific line shapes and stop/start points.

    Now, the question is, will other conditions produce the same line shapes?

    Consider how the reference is designed. Your taking an area based on foot orientation as the primary reference, then using a line on one side to define a specific relationship to that area. So, even though foot orientation is used to define the primary reference (the area of the base of support), the actual relationship which is being recorded is the relationship to one side of that area.

    So, the actual reference is a line between the points on one side. The area could have any shape and area due to abnormal foot orientation, but as long as those points stay in the same location, the measurement system would not detect any difference.

    Indeed, it doesn't even have to be the same points on the feet which define the real reference, the line. As long as the points are in the same location, the measurement system has no way of determining what points on the feet are associated with the reference points. This approach is hopelessly flawed.

    It can be "improved", in that you can include some caveats, but it's use really should be discontinued. (If I published this, do you think anyone would just believe me, despite the unquestionable logic? Do you believe this?)

    Application of my methodology totally solves this problem, as you might have guessed. As will this method solve (expose) all problems in current measures and techniques which are associated with the description and interpretations of body segment positions. Mine is the universal standard.

    The only thing wrong with the base of support measure is that it uses an improper reference.

    In my system, for the single stance, the foot-line grid (FLgr) provides the correct reference, and for double stance the L-R grid (L-Rgr) is the proper reference.

    The FLgr is in the horizontal plane and uses the heel-point as the (0,0), and the y-axis is along the foot-line, and is the reference during single stance. This defines the real body segment (foot) position (projection). Notice there is no interpretation here, I'm not saying the foot position is important. But, since the foot-line defines a real body segment and it's fully correlated in the measurement system, relationships described with respect to the foot-line are also fully correlated to the global body position.

    In order to study the relevance of the area "base of support", you'd plot the foot contact area (or whatever) as co-ordinates on the FLgr, and the trajectory of the COM (or whatever) on the FLgr, then correlate the 2 according to their mutual relationships to the real body segment, the foot(-line).

    This may seem roundabout, but it's the only 100% technically valid way to do it. This removes all interpretation. Plots here would uniquely describe all possible orientations and trajectories, except those which differ purely in the vertical co-ordinates. I doubt purely vertical variance could ever happen, but, even if it did, other elements already within the system take that in to account without the need for secondary correlation. That isn't a problem, I assure you.

    The primary reference for the double stance is the line connecting the heel-points of the feet. If anyone is interested as to why this is proper (and why it doesn't include the foot-lines), I'd be glad to describe it at a different time, since this is a long post already.

    I'm sure you'll agree that this is the proper way to study this issue. If you disagree, please post why and how you would approach this. The FLgr and L-Rgr are already part of this analysis method, so I don't even have to make any extensions to solve this problem. It's done. Now, it's a matter of collecting examples.

    I could continue, but I'll give you a break.

    I'll end with a bit of a reality check. Just look at what I've said up till now. Even if only some of it's true it would be worthwhile to pursue (all of it is true). The only vital requirement which I can't provide is data. When you suggest I go generate new data, you have no idea of the practical difficulties associated with that. It's really not realistic (yet). And, there's no need. That's like trying to punish me for doing this.

    There's perfectly suitable archived data available right now, so I can start the explanations and developments immediately. All I need is a bit of co-operation.

    Even if you don't have access to the data yourself, I'd bet know someone who does.

    Let me put it this way. If I came to your office in person, sat down and explained everything as I have here, and then said that all you have to do to greatly help this endeavour, and have your name associated with a very significant advancement, is to swing around in your chair, open a file drawer, pull out a file and hand it to me, would you do it?

    And, if you didn't have a file in the office, would you call a friend for the file? Considering the potential benefits.

    Is it really that much?

    But, I realise you still may not see what I'm saying. I may have gone too quickly into the application without adequately explaining the fundamental logic.

    If anyone is still interested, I'll be glad to post a more detailed explanation of why the fundamental parameters, which describe the positions of the feet with respect to the pelvis-line, are the most important elements of gait (as far as measurements), and why the horizontal plane is the most important, and the only one needed for most of the analysis. Do you recognise the importance of the 8 fundamental parameters?

    If anyone is willing to keep trying to understand, please post. Really, I'm offering so much for so little, just look at the things I've said and the problems which are solved by this method. It just may take a little time for you to get used to the perspective.

    I appreciate the advice on how to proceed, but I'm sure that the approach I'm taking now is the most practical. All I'm asking for is data, and no animals will be harmed while doing the analysis. You can judge the results yourself.

    Walking is using the 3d body position to provide a 2d result. There are now suitable techniques to measure the 3d position, but none which properly show its relationship to the 2d result. Oh yes, until now.

    I look forward to responses.

    Mike M

    PS No problem about the name Michael, as the saying goes, "just don't call me late for supper". And, you can call me "stupid a**h*le" if you like, just please keep responding.

    PPS Just to refresh your memory, the requirement is marker data in mm (preferably, but any linear units are OK) for the hips, knees, ankles, heels, toes, and one marker which is always behind the pelvis-line, like T10. If there are more markers in the set, I'll take them all, if that's all right, but limit the initial analysis to the core elements.
  25. Last April you were trying to find someone to send you 3d marker data, today: at the bottom of your monologue- your still looking for 3D marker data- status quo. How many people from this Arena have sent you 3d marker data? What does this tell you?
    The reason no one is jumping up and sending you 3d data is because few clinicians have access to this technology and / or use it regularly in patient work ups. You need to demonstrate that your system is sensitive enough to detect changes from treatment interventions. By this I mean you need to take a series of patients and demonstrate the systems predictive value against the current gold standards. Write it up and have it published in a peer reviewed journal. If I had 3d analysis equipment I could already do all of the things you mention above, so why do I need to use your system? "Because it's better" -right? PROVE IT.

    Have you submitted a manuscript to the journals I suggested? If you have and they have rejected your manuscript, what does this tell you? If you have not submitted a manuscript- get on and do it. The effort you put into writing here, would be much better placed working on a manuscript for submission.
    While it may be clear to you, until you write this up and have it scrutinised by your peers this is unlikely to ever be clear to anyone else.
    Try picking up a telephone. If people aren't returning your calls or replying to your e-mails, ask yourself why?
    This tells me everything I need to know.:hammer:
    Everyone else is wrong and you're right, Mike. Like I said, good luck with your future. Why do you think people aren't jumping up to try and help you?

    P.S. Given your confidence in your system, why don't you just go out and buy the equipment you need? Or self-fund a project via a University that has the equipment you need? It's very simple.
  26. m.mouck

    m.mouck Active Member

    Thank you very much for the response Simon.

    Of course, you must realise that I have to defend myself with respect to the statements you've made. This is difficult enough without having people think that the statements you've made are justified or realistic. (But I still appreciate them very much.)

    Regarding your statement, "Everyone else is wrong and you're right, Mike," regarding my statements about the inaccuracies in current methods. It's not surprising you're not aware of the obvious technical deficiencies in at least some current methods. Why would you question them.

    But, I get the impression that this is an attempt to dispute the material which I've presented. In a manner, I have to be honest with you, which I consider not very honorable.

    I discuss this material on this forum in good faith. I have no ulterior motives except the advancement of knowledge, so I must object when you insinuate error without proving any. This is very bad karma in the research world.

    If you dispute the material, please do it directly.

    You're implying that "everyone else" is right, without even attempting to dispute any of the material which I've presented. "Everyone else" once "knew" that the universe revolved around the earth.

    For eg., do you dispute the base of support method analysis, or dispute that my method solves all of the problems of the other system. Do you understand the problems with the other system?

    I've taken a system which gives the same line shape for any number of different orientations, and converted it into a reference system which not only uniquely describes all possible orientations, but supplies the required elements to study the relationship of point and line movements to the area known as base of support, which is the original desire, in an accurate and valid manner.

    Is there any flaw in this reasoning? After all I've said, do you really question my technical ability to judge elements such as this. Can you acknowledge there's at least a chance I know what I'm talking about, in other words, that you have no way to dispute anything I've said to date regarding the technical aspects of the method or associated statements. Can you really dispute anything. I'd hazard to say you can't.

    Perhaps you dispute the statements regarding stride and step length. Do you recognize the error associated with each?

    You're likely familiar with the old adage, "When you argue properly, you can never be proven wrong." I don't like this because it implies that even deceptive tactics are acceptable as long as it leads to the conclusion that you "argued properly".

    My equivalent to this is, "When you develop an analytical methodology properly, it's indisputable."

    If I've made an error or unjustified statement, I want to confront it and deal with it. I have no emotional attachment to the material. I'm not offended if someone says that I'm wrong, but if I am wrong, I only expect that you can describe how I'm wrong, since you've apparently judged it to be so in some way. If there's a problem, spit it out, please.

    As far as your ability to go and use 3d already. I have no idea what you have available, and there may be current methods which give you all the information you need to know, in which case this would be superfluous. But, since you obviously don't see the relevance of the information which I provide, how could you possibly judge what benefit it would be compared to current methods.

    You've made an unjustified statement that what I provide is available by current methods. I defy you to prove this is true. And, I must go on to state that I declare unequivocally that this is absolutely not true.

    To illustrate, I've used the term "central reference" often, I don't mean to be insulting, but do you understand what I mean by this? Your statements suggest you don't, but I could be misinterpreting. For eg., this method provides the central reference for pressure pad data analysis. Can you tell me in what way this method will enhance pressure pad data analysis?

    If you can't do this and more then I hope you don't actually consider yourself a valid judge.

    I posted a "quote" on another thread which stated, "A good researcher knows how to use the knowledge of others, but a great one can also distinguish knowledge from opinion.

    What do you think I'm presenting here, knowledge or opinion.

    I must admit that I included one statement in the last post which is designed as a test to gauge ability to discuss this issue. This was the statement that I haven't received permission to discuss one of the data files yet.

    Of the different ways to interpret this, Simon, you've chosen the most negative, and you also insinuate that this is a reflection of some problem with the work. Again, without any proof whatsoever. (And, you've added a foolish icon, perhaps in an attempt to lend legitimacy to your statement.)

    All this means is that this person also doesn't understand the application, since I've explained only a fraction of the material to them. Notice, Simon, that you didn't even attempt to consider what the file was or what the work-up showed. It's an excellent picture of a positive Trendelenburg sign, and the associated consequences to the gait pattern, by the way.

    In my day, when info was shared like this, it was understood we could discuss it in any way necessary, but I'm not sure if things are like that for this area. And, Simon, do you consider it a positive reflection on the method that the person who gave me the main data set gave me permission to use and discuss the material in any way needed?

    Anyway, you're response to the statement shows clearly that you're allowing your emotions to influence your judgement. Most people do this normally, but emotion is poison to a scientific discussion.

    As a result, you've made several statements insinuating error or problems with the work, and none of them are valid or justified. I hope your frivolous manner of discussion and constant innuendo don't trick people in to thinking that there are problems with the work, there certainly isn't.

    Please control your use of insinuation and innuendo, these are petty debate tricks designed for deception. Again, if you dispute the material, please do it directly.

    Very early on I had a person stop responding when I started to define the terms I needed. He was offended, apparently, because I'm not "Noah Webster". If you're offended in some way that I dare discuss these issues, you always have the option of not reading it.

    Thank you for your suggestion on how to proceed with the development. I'M TRYING TO PROVE IT. would be an appropriate response, I believe. You apparently believe that in order to prove it, I have to generate new data. This method is not about data collection, it's about data analysis.

    Do you really think that I lack the ability to design suitable experiments? Do you really think that I haven't considered submitting a paper to a journal? It may seem like the logical course of action to you, but you do not appreciate the practical realities.

    Until I can determine how to explain the information so others can understand the applications, submitting papers is utterly useless. They simply won't be understood. This is why I believe the course I've chosen is the only logical one. I'm seeking people who deal with gait analysis and who are interested in advancing knowledge.

    I hope to explain the info to them in order to determine which manner of explanation is most suitable and clear. When I've determined why people don't understand, and figured out how to explain it so they do, that will be the time to publish a paper.

    Thank you Simon for enlightening me that no one has the ability to provide data. If I had known that at the beginning, I could have shifted the focus.

    I find it hard to believe that understanding gait wouldn't be important to podiatry. Even if you don't use 3d techniques, if you use visual analysis for diagnosis, I would think you would be interested in this material, since it may expose realities of the walking process which can't be described by other methods.

    I don't mean to single you out, Michael W, but you stated it was confusing. Thank you for being honest, and this is something which can be addressed, if you wish. Even without 3d data from your area, I'm very willing to continue the explanation. It's only talking.

    I have sufficient real examples to facilitate the discussion. I have a person turning a corner, walking backwards, stepping in place, during early, mid and late conditioning on a rotating wheel, and sighted and blind walking before and after conditioning.

    Since I was focussed on getting data relevant to your area, I skipped the discussion of the basic principles. If even one person wishes to be involved in an excellent mental exercise, I'll continue with a description of the central importance of the 8 parameters, and why the horizontal plane is so important.

    Again, my motivation is purely the advancement of knowledge. When people stop posting, so will I.

    And, I hope you understand that if any unjustified negative comments are made regarding the work, I must confront them.

    Mike M

    PS Thank you for the suggestion I buy my own 3d rig, etc., Simon. But, you apparently don't realize that this is equivalent to the statement, "Let them eat cake." And, thank you for the encouragement, Good luck with your future as well.
  27. Attached Files:

  28. Graham

    Graham RIP

    Mouck = Ptolomy:bash:
  29. Graham

    Graham RIP

    Simon = Capernicus;)
  30. Mike,
    Here is what I would do if I were in your shoes: I would write a theoretical paper including examples employing deductive logic to outline (and showcase) your method of gait analysis and submit it to a high profile journal. The publication process will help you identify any flaws in your theory and/ or improve your writing technique and style. Once published, you may find interest from someone who can help you take this on to the next level. This way, you can bypass the data collection bit for now and it will, at least, move you on.

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