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
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
And, all the fundamental parameters have a unique physical
basis, and the other measurements are just products of them.
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
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
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
- direction change:
a) foot angle,
b) foot offset,
- distance change:
Note: b) and d) have a fixed
relationship, since they are the sides of a right triangle, with the
pelvis-line as the hypotenuse.
- distance and direction change:
a) aberrations leading to
heel-point shifts and foot-line rotations
- no effect on distance or direction:
a) mass shift,
B2. Time Dependent Values
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 Modelís
grid is essential for accurate, consistent interpretation.
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
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.
Part I Part II