Definition: Training in exercise activities other than your primary sport, to improve fitness without over-taxing the muscles used in your primary sport. Walkers often do weight training to strengthen their upper body, which is not exercised by walking. Bicycling is also good crosstraining for walkers, because it exercises the quadriceps muscles in the thighs which are not exercised in walking (although racewalking does exercise the quadriceps).
Pronunciation: cross-trayn-ing (noun)
Examples:
I am going to crosstrain by lifting weights.
