1. Interval Running. This consists of intense running or sprinting for short distances, followed by walking or complete rest. For instance, you can mimic the energy demands of football by doing an exercise intensely for 3-5 seconds and follow it with 20-40 seconds of rest. This is like the format of a game, where you work hard during a play, and then have a short recovery period before the next play.
2. Sled Work. Pushing or pulling a weighted sled is a great way to prepare for the conditioning needs of sports like football and wrestling. It's especially great to do it in a group of four to six athletes. One athlete can push (or pull) the sled a short distance. He or she can then recover while the other athletes take their turn. Repeat 10-12 times or alternate a push set with a pull set.
3. Circuits. Choose 8 to 12 exercises that engage a variety of muscle groups. Perform 10 reps of an exercise, and then partially recover while moving to the next station/exercise. Repeat the circuit after a long rest period.