Cross-training is when a person combines exercises from several kinds of disciplines, rather than one particular discipline. Effective cross-training improves overall performance and fitness, without putting too much stress on any portion of the body.
An example of successful cross-training includes a runner who takes time to work on his pelvic, abdominal and arm muscles. Although leg muscles are used the most when running, these other areas are also utilized. Consequently, focusing on the less-used areas of the body makes the person a better runner in general. The most common form of cross-training is combining weight lifting with cardiovascular exercises.