MUD Mired in time...

MUD:

Step lengths Stride lengths [a recap] All sorts of measures derive from measuring mud print distances. Can the left step length be twice the size of the right step length? Well after enough steps the feet would be miles apart if THAT were true. FUNCTIONAL step length is how far the center of mass travels for each step. That is what both walking and stepping are for, to move the body from hither to thither. A video exam tool that lets you pull lines and automatically gives you the center of that line makes tracking centers easy which is good for knee centers and mass centers also. . This point gives you a point in space ____ as does this line (using its center). BEWARE Step length (“shortened stride length”) error is everywhere. Every malady “causes” shortened stride length… no … compensation for energy insufficiency uses a shorter body travel to get by. Restated: Shortened arc of travel over an elongated center of mass to ground wheel spoke (radius) has small vertical rise and so isn't a malady but rather a compensatory mechanism to get some distance with least up/down (= least energy) cost. Human interfaces can be modified such that the linkages are 'IN TUNE” with the body linkages. Minus that, people powered things tend to kill. A Tour de France competitor, who never finished , finally placed once his pedal lengths were changed to harmonize with his leg segments. We observed epicycles at the top & bottom of each pedal stroke & fixed that by altering length of pedal from pedal axis. A spinal fusion to the pelvis kills lumbar centered vertical hip oscillation. As the center of mass to hip center distances are nearly the same as the ankle to metatarsal heads... you cannot wear high heels with that fusion. Wearing high heels (limits available ankle modulation) makes the two hips alternately rise & fall more, thus leading to marriage and babies.. sometimes.