In the 1970s, there was a significant increase in the popularity of running as a form of exercise. It was acknowledged that footwear-induced changes in movement could alleviate some of the stress and strain imposed on runners as their mileage increased (Frederick 1986). It was also suggested that running footwear could be a risk factor for cumulative microtrauma or overuse injury (Taunton et al. 2002). At this time, biomechanists sought to understand the mechanics of running and to relate the mechanics to injury prevention. Researchers also attempted to use the findings of their research to help design footwear that would accomplish the goal of reducing overuse injury. In order to respond to this goal, many biomechanists used a kinematic approach to solve the problem. Kinematics is the description of movement (i.e., position, velocity, or acceleration) without regard to the forces that cause the movement.