The Mouck Method for Gait Analysis & Path Deviation Study

Part IV - The Step Model and Footfall Plots

5. Plotting Results

Error +/- 0.02” (approx. 1 1/4 sixty fourths of an inch). All the error is from plotting, since all measures are fixed or calculated values.

Some deviations are small but "exact". A difference of 0.04” is real. All lines are in inches and all angles in degrees.

Tables such as the ones below make it easier to compare the changes in each measurement caused by one or more specific parameter changes. This should be useful for computer modeling and the production of correlation tables, as well as to highlight the potentially great variability in gait which gives rise to similar overall patterns. All plots have 0 pelvic-stretch and no aberrations.

6. Plotting Results Analysis

Note: Some conclusions are from data not shown.

1. Step-line
   1. Different step-lines for the left vs right feet do not cause turns.
   2. Step-line is decreased by foot offset, the same for CW and CCW rotation.
2. Stride-line
   1. Stride-line for the other foot increases with external rotations per step, and decreases with internal.
   2. A person can be turning with every step, but still walking straight.
   3. Measured equality of stride-line doesn't mean the person is walking straight. Non-compensating foot offsets
      cause an extra angular path shift, even though the left and right stride-lines are the same.
3. L/R-line
   1. Changing straddle, step-out or rear-leg lines, pelvic stretch and/or foot offset changes L/R-line.
   2. Foot offset is shown in the forward foot. ie. if the left foot had a foot offset left, the L/R-line wouldn’t change,
      but the R/L-line changes.
   3. Shorter step-line is shown in the forward foot. ie. if the left foot had a shorter step-line, the L/R-line wouldn’t change, but the R/L-line would decrease.
   4. Foot and push-off angles do not change the L/R-line (So, angles vs. offset rotations have a different effect on the L/R-line.)
4. Walking-straddle
   1. For foot angles: 1) inside turns increase, and 2) outside turns decrease the walking-straddle for the other foot. Foot angle doesn't change the Wstr for the same foot.
   2. For foot offset: 1) inside turns decrease the walking-straddle for the same foot, and increase it for the other foot, and 2) outside turns do the opposite.
   3. Foot angle changes the walking-straddle by twice as much as the equivalent angular change as foot offset, for the range of values used here. 1 deg of foot angle changes the other foot's walking-straddle by 0.26", while one degree leg angle of foot offset changes both walking-straddles by 0.13".
      

      Changes to Wstr for L15{0}[15]R15{0}[15]
      		same foot	other foot
      foot angle:	outside turn	0 decr.	0.26/deg
      	inside turn	0 incr.	0.26/deg
      foot offset:	outside turn	incr. 0.13/deg	decr. 0.13/deg
      	inside turn	decr. 0.13/deg	incr. 0.13/deg

   4. Wstr variations are cumulative.
      For L15{0}[15]R15{0}[15]str8:L(5)L-5L:R10R; from standard plots, LWstr = RWstr = 6.02. Walking "straight", both feet outside turns. Extra angular shift left due to the foot offset.
      

      		RWstr	LWstr
      str		8.00	8.00
      From left step	(5)L	-0.65	+0.65
      	5L	-1.3	0
      From right step	10R	0	-2.6
      		6.05	6.05

      
      For L15{0}[15]R15{0}[15]str8:L10L:R10R; from standard plots, LWstr = RWstr = 5.35. Walking "straight", both feet outside turns.
      

      		RWstr	LWstr
      str		8.00	8.00
      From left step	10L	-2.6	0
      From right step	10R	0	-2.6
      		5.4	5.4

      
      For L15{0}[15]R15{0}[15]str8:L(10)R; from standard plots, RWstr = 9.27, LWstr = 6.69.
      Inside turn of 10 deg right (CW) with every left step. Extra angular shift right with every left step due to the foot offset.
      

      		RWstr	LWstr
      str		8.00	8.00
      From left step	10R	+1.3	-1.3
      From right step	0	0	-2.6
      		9.3	6.7

5. Etc, etc

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