Article: In the vaulting events, gymnasts sprint down a 25 metres (82 ft) runway, jump onto a spring filled board or perform a roundoff, or handspring entry onto a springboard (run/ take-off segment), land momentarily, inverted on the hands on the vaulting horse, or vaulting table (pre flight segment), then propel themselves forward or backward, off of this platform to a two footed landing (post flight segment). Every gymnast starts at a different point on the vault runway depending on their height and strength. The post flight segment may include one or more multiple saltos or somersaults, and/or twisting movements. A round-off entry vault, called a Yurchenko, is the most common vault in elite level gymnastics. When performing a yurchenko, gymnasts "round-off" so hands are on the runway while the feet land on the springboard (beatboard). From the roundoff position the gymnast travels backwards and executes a backhandspring so that the hands land on the vaulting table. The gymnast then blocks off the vaulting platform into various twisting and/or somersaulting combinations. The post flight segment brings the gymnast to her feet.

Question: What determines where a vaulter starts on the runway?
their height and strength