The breathtaking violence of an ordinary NFL hit. Applying physics to the NFL, like calculating ” … the force with which a great NFL runner-receiver makes a lateral cut. It’s one of the most transfixingly elegant moves on the field — “They almost teleport,” Gay says admiringly — and he wanted to measure it. There are two forces being exerted when a player hard-plants his foot — that of the body, and that of the turf. “The ground obeys Newton’s Third Law and pushes back on him with the same force,” Gay says. “About 800 pounds of force shoot through his ankle and his foot.” Emphasis mine!