The cleated football shoe hit the ground with 237 pounds of force and pivoted abruptly in a counter-clockwise direction, as one might do while running a tight pass route. But there was no human foot in the shoe, just Pennfoot. It’s a device invented by Pennsylvania State University researchers to measure traction between shoe and surface, to help groundskeepers and sports teams minimize injury. Athletes like a lot of linear traction so they can start and stop quickly. But Pennfoot measures its unwanted cousin: rotational traction – the amount of torque exerted on the shoe when it tries to pivot. Read more here