The word means "speed play" in Swedish, and fartlek training given its varying running intensity perfectly mirrors what happens in soccer games. Runners perform fartleks by timing alternate sprints and jogs, based on a watch or heart-rate monitor. The intensity can change based on light poles or even dogs seen in the park. For soccer, you can adapt sport-specific fartlek drills.
Dribble and Shoot
This ingenious drill, from strength coach Greg Gatz's "Complete Conditioning for Soccer," weaves skills work in with soccer conditioning. You stand at the end line with a ball while a teammate stands at the midfield line. Dribble quickly toward your teammate. Pass the ball to your teammate and turn, taking a long bending run toward goal. Have your teammate serve the ball ahead of you as you close in on the goal and take a shot. Perform four repetitions as a shooter, take a rest of three minutes, and complete three sets.
Gatz also places his University of North Carolina soccer athletes through the sprint-jog-walk drill. You'll need a watch with a stopwatch function or a heart-rate monitor. You simply continuously sprint for 10 seconds, jog for 20 seconds and walk for 10 seconds for a total of 10 minutes. Put some fancy curves and angles in your pattern of running. Rest for two minutes after each set and complete two or three sets.