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How to Calculate Leg Splay

In bipedal walking, leg splay refers to the degree to which the legs swing back and forth relative to their state at rest. It is a measurement of the angle of deviation along the vertical axis between a leg that is standing still and a leg that is leaning toward the outside of the body to pivot while the other one swings to take a step. Leg splay is an important measurement for orthopedic physicians and can be calculated with a few simple measurements.

Things You'll Need

Video camera
Tripod
Tracing paper
Pencil
Ruler
Protractor

Instructions

- 1
  Mount a video camera roughly 2 feet off of the ground and fix it in focus at a specific point on the wall.
- 2
  Instruct your subject to stand at rest directly in front of the camera. Check the view to ensure that both of your subject's legs are in the shot. Begin to record the subject.
- 3
  Instruct your subject to walk directly toward the spot on the wall at which your camera lens is focused. Stop the recording when your subject is finished.
- 4
  Play back the video. Pause the playback at the beginning and place the tracing paper directly onto the screen. Use the straight edge to trace the angle of the leg with which your subject takes his or her second step while it is at rest.
- 5
  Resume the video and pause it at the apex of the pivoting leg's lean outward during the first step. Trace the angle of the pivoting leg.
- 6
  Measure the angle of deviation from the resting line that you have drawn on your tracing paper to obtain your subject's splay for the pivoting leg.
- 7
  Repeat Steps 4 through 6 for the opposite leg to obtain its angle of splay.

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