Apparently a high percentage of chefs at Chinese restaurants suffer shoulder plane from wok tossing. They must rapidly move the heavy pan to launch the food into the air so it cooks but doesn't burn, even though the temperatures may hit 1200°C. Recently, Georgia Tech mechanical engineers studied the kinematics of Chinese restaurant chefs to understand how they actually move and the "optimal regime for making fried rice." According to their scientific paper, they hope their study can not only lead to better fried rice for all but also "inspire the design of stir-fry robotics and exoskeletons to reduce the rate of muscle strain injury among professional chefs." From their scientific paper:
Tossing is a combination of two independent motions, a side to side motion and a see-saw motion, allowing rice grains to slide around the wok as well as to jump off the surface. We identify two critical parameters that chefs can vary: the frequency of tossing and the phase lag between the two motions applied. By filming professional chefs, we found that, at the frequency chosen by chefs, the phase difference performed is optimal for mixing. We suggest that future chefs increase the frequency of motion, which may enable rice to jump further, and promote cooling and mixing.
"The physics of tossing fried rice" (Journal of the Royal Society Interface via Science News)