A sure fire way to avoid the possibility of an injury is to cross train. Working muscle groups that you normally don't use permits those muscles that are well toned to take a break. When a runner cross trains by exchanging a run for a swim workout or a cyclist cross trains by exchanging a ride for a rowing workout, the athlete is lessening the risk of an overuse injury. Since over training accounts for a high percentage of exercises injuries, cross training represents a significant benefit by reducing trauma.