Development of a highly adjustable cushioned treadmill

The treadmill is favoured by many due to the reduction of impact forces on joints in comparison to overground locomotion. The treadmill allows users to set the distance, speed and gradient, however, currently surface properties can not be adjusted. At impact with the ground the foot undergoes a rapid change in velocity creating high forces to be transmitted throughout the body. Repeat exposure to such shocks is thought to be responsible for the widespread overuse-type injuries (Cavanagh 1990). Literature is available on the kinematics and energy expenditure of various overground surfaces, however, not specifically for treadmills providing surface stiffness and damping adjustments. A cushioned treadmill has been conceived and designed which permits the running/walking surface to be adjusted for stiffness and damping. The concept has been designed to be implemented on home/commercial treadmills unlike Kerdok et al. (2002) who created a bespoke laboratory treadmill rig to evaluate the energetics and mechanics of running on surfaces of different stiffnesses. The new concept is thought to provide enhanced user functionality which to date has yet to be achieved in a mass market version. The locomotion kinematics and associated energy cost over a range of surface settings is to be evaluated, along with the rating of perceived exertion. The design is presented and discussed, along with the methodology for evaluation.