Wind sprints are a technique to improve your cardiovascular fitness where a long session of aerobic activity is interlaced with short bursts of anaerobic activity (i.e. sprints). These short bursts will ultimately improve your aerobic performance. It is used primarily to improve running but can be adapted to any exercise you do such as cycling, swimming, and cross-country skiing.

http://www.theadrenalist.com/sports/why-you-should-add-wind-sprints-to-your-workout-routine/