An apparatus for shifting the body weight of a runner from a runner's legs to a wheeled frame for enhancing the runner's performance and minimizing leg strain comprises a loop of elastic rod-shaped material stretchable during standing and during running movement. A base bend of the elastic is secured to a pelvic harness at the top of the back of each leg, and another bend of the elastic is secured to the wheeled frame. A third bend is supported on pulleys mounted on a height adjustable tee on the wheeled frame. This brings about a significant shift of the runner's weight from the runner's legs to the wheeled frame.