For a shoe designer, friction would be of tantamount importance. Without friction, people would not be able to walk, run, jump, change directions, or any of the other motion-related things they are able to do as a norm. Friction is a force of opposition to motion, generated by two surfaces rubbing together by their contact between each other. A good test would be a tug-of-war contest. The team that has the better friction between their feet and the ground, or the floor, usually wins the contest. Another good test to try out the "friction component" of my new shoe would be a series of suicide drills where the participants have to change their direction as quickly as possible. A good force of friction between the shoe sole and the floor is very important to change direction quickly. And last, but not least, the good old-fashioned 100 yard dash would be a good proving ground to show my shoes improved "fiction-grip" over that of my nearest competitor.