MUD Mired in time...

Swing phase is NOT the leg but rather the swinging thigh which is a concentric and a brief act of the psoas. The iliopsoas muscle is not IN the leg. It is in the body with segmental arteries serving it as the source of almost all the energy of walking which is briefly put into the swing – similar to pushing a child on a swing. The oomph it provides is brief as with pushing a kid on a swing. The swing and return follow from pendulum related momentum etc. A stride is two steps.

When considering only one STEP, we use the same stature circle but the radius of that circle is now the ruler. We use stature and half stature for stride and for step measurement. In symmetric gait we expect the stride and step numbers to be about the same. Easy. Don't go back in the mud to measure FUNCTIONAL step lengths. Although the mud measure of heel to heel is convenient -WHEN NORMAL, it becomes misleading when dissecting abnormalities. Mud step lengths MUST always be the same. If not, the body would be ripped apart by unequal steps. Abnormality such as 'step to' has one leg claim new ground and the other catches up. They are equal in length but not in what they do.