A second zigzag, generated by surface electrodes attached to the USC diver's skin, records muscle firing patterns throughout the dive. She clicks on a long jumper's toe, ankle, knee, and hip. Each point represents an x,y coordinate. Once this data is poured into an Excel file, McNitt-Gray can calculate through every phase of the jump the body's center of mass, velocity, and joint angles. The seemingly simple problem is actually devilishly complex.
Most sports provide built-in mats in the form of athletic shoes.
Gymnasts, however, perform barefoot. In this sport, not only must the mat be able to absorb the energy at impact, McNitt-Gray notes. It has to be stable enough so the gymnast can land without bouncing steps or hops. It also needs to incorporate protective qualities to avoid a repetition of the tragedy that struck Chinese gymnast Sang Lan at the 1998 Goodwill Games.