"From numerics to animation, Mathematica is a total environment. I also really depend on the MathLink feature to add special capability to my sports biomechanics work."

• Numeric
• Symbolic
• Graphic
• Notebook
• MathLink
• Animation

Running is certainly a good way to exercise; however, it does cause the body to weather a certain amount of shock each time its feet hit the ground. Chikara Miyaji, a sports biomechanics researcher at the Institute of Health and Sport Sciences in Japan, uses Mathematica to analyze the motion of runners to examine how they move and how they can move more efficiently to reduce the shock to the body.

Using video processing, Miyaji tracks the movement of the body and automatically digitizes the information based on model matching. A two-dimensional human body model and the captured human body image are superimposed, and, using Mathematica, the body positions are calculated to minimize the difference between the two images.

"I first use C to do low-level processing that assesses the pixel-level information for each frame. I then use MathLink to connect the work I did in C with Mathematica for the numerical computation and the high-level routines that predict the body's movement," Miyaji said. "Using MathLink to interface a low-level C program with Mathematica is an excellent approach for video image processing."

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