The Mouck Method for Gait Analysis & Path Deviation Study

Part V - Applications and Acknowledgements

B. Clinical Gait Analysis

Each step is an individual. A person walking is a mechanical instrument. A person walking is a vector system. Walking is a controlled stagger. The primary goals of walking are distance and direction. Walking is a complex, personal attribute. Walking is the manipulation of the 8 fundamental parameters of gait. Etc., etc.

Walking can be described in many ways, and each different perspective highlights specific factors which uniquely contribute to a person's gait pattern.

This method is a new way to describe gait.

Changes in step and stride-line and walking-straddle can now be related to foot offset, foot angle, push-off angle, heel-point shifts and foot angle changes over aberrations, step-out, step, carry, L/R, rear-leg and straddle lines and pelvic-stretch, and all of these for every step over the path.

And, all the fundamental parameters have a unique physical basis, and the other measurements are just products of them.

This approach is very flexible, and the general strategy is valid even if different points are tracked. Study of different aspects of gait may be easier if other reference points or lines are incorporated into the Step Model. Then, variations in these can be directly related to the specific direction and distance changes over a step, as well as rotations of the basic grid.

This method can be applied immediately for the tracking of changes over treatment. But, application to diagnosis will require some research into normal and known deviant step patterns. Once described, however, the data, graphs and correlation diagrams which can be derived using this measurement system will make for a very powerful diagnostic tool.

B1. 2D Classification System

One of the main difficulties in current gait work, besides the problems outlined in Part II, is the lack of critical co-relations. Any complex study, such as gait analysis, requires the recognition and definition of central threads which can be used to organize the many and varied facets of modern research.

For gait analysis, the 8 fundamental parameters provide those central threads, and they are the foundation for a primary classification system to describe point and line movements, wrt effects on distance and direction over a single step.

All movements for a person walking will do one or more of only 4 things, and each category will be further subdivided, potentially all the way to specific muscles and joint rotations:

1. direction change:
   a) foot angle,
   b) foot offset,
   c) push-off angle'
2. distance change:
   a) rear-leg-line,
   b) pelvic-stretch,
   c) step-out-line,
   d) straddle-line
   Note: b) and d) have a fixed relationship, since they are the sides of a right triangle, with the pelvis-line as the hypotenuse.
3. distance and direction change:
   a) aberrations leading to heel-point shifts and foot-line rotations
4. no effect on distance or direction:
   a) mass shift,
   b) comfort,
   c) desire,
   d) balance,
   e) etc.

B2. Time Dependent Values

Time dependant parameters can be tracked the same as is currently done. Comparisons of relevant snapshots, wrt elapsed time, will give all the currently studied values, since this is just tracking points from a different perspective.

The rotating reference grid is a major benefit to this area. Since point trajectories are vectors, knowing their relationships to the Step Model’s grid is essential for accurate, consistent interpretation.

Also, time dependant analysis wrt the fundamental parameters should provide a way to better isolate and define the specific factors affecting gait. Deviation factors could compare linear and angular deviation wrt the final or standard value, and this should lead to a read-out profile indicative of specific ailments. Other points and lines could be tracked in the same way. This could be a very important application.

But, time analysis entails specific variations that require correction factors to account for limitations in all current measurement systems. The main requirement is the identification of the 4 points and foot-line, but, since the pelvic joints are inside the body, and the heel-point is on the sole of the foot, the exact positions of these must be estimated using available position marker data.

Fortunately, the individual direction changes over a step appear to be very large, in general, and minor inaccuracies in pin-pointing the exact positions of the 4 points and line will likely be insignificant for most applications.

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