Training programs are essential for optimal performance in sport as well as the prevention of injuries. These programs are custom tailored to meet the needs of the athlete. If the athlete is a vertical athlete, for example, the training program will include explosive exercises to build the proper type of fiber in the muscles that are recruited for jumping. Muscle fiber type is something that varies from athlete to athlete and they can be converted from one type to another. This is important to know when designing the training program because the wrong type of exercises could convert explosive fibers in a sprinter to endurance fibers which will impede the sprinters performance. The proper training regimen will also help protect the athlete from unwanted overuse injuries as well as acute injuries. This is accomplished by ensuring that the program design includes the proper amount of core strengthening, flexibility work, speed work, endurance work and explosive work.