A long-jumper aiming for a world record or even a personal best might learn a lot by mimicking Carl Lewis. But, ultimately, a strategy that works for one jumper might not be the best for another. To better match the jump to the jumper, a UC Davis researcher is developing a computer simulation model that can be used to design athletic performances tailored to an individual's unique physique and style. For a world-class jumper, bettering a personal best might mean a world record or an Olympic gold medal, says professor Melvin Ramey, chair of the department of civil and environmental engineering and an assistant track coach at UC Davis. Ramey first became interested in the biomechanics of human jumping while he was an undergraduate engineering student and competitive collegiate jumper. He showed that one of the crucial components of long jumping is angular momentum, which is a kind of balancing force generated by the swinging arms and spinning legs in the flight phase. Since then, Ramey has developed a computer model with a realistic stick figure acting out behind-the-scene equations of mechanics that follow Newton's laws of motion. So far, Ramey has been working on the take-off and flight phases of the jump, where angular momentum plays an important but invisible role. Eventually, he hopes coaches will be able to tinker with the computer athlete to find the keys to improving real-life performances. The research may also have rehabilitation applications.