Mapping Human Muscle Movement

Look at the flashes of red when the legs walk forward. These are the working muscles as they contract; the muscles in yellow are at rest. Rehabilitation medicine specialists use this imaging technology for gait analysis, how people walk or run. By mapping how a person uses muscles, therapists can help patients learn how to move better.

Explains Karen Siegel, a Research Physical Therapist in the Human Movement Disorders Section of the Physical Disabilities Branch, Rehabilitation Medicine Department, NIH Clinical Center: "How patients cope with movement disorders, how they compensate for weak or missing muscle groups are important in rehabilitation." By studying which muscle groups become active at what point in a movement, scientists like Siegel can target specific muscle areas for special exercises or other help.

What would happen if the scientists wanted to study your gait? First, they'd tape about 30 small (3/4") reflective balls along your legs and feet. You'd walk back and forth in front of six infrared cameras that record the light bouncing off the reflective balls. Those images go into a computer that lines up (calibrates) the reflective balls according to targets on a skeleton. The images are then set into motion through animation.

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