Check out FloTrack's WOD featuring Stanford's Sean McGorty and Grant Fisher doing 800m repeats last fall over UVA's cross country course. They performed 7 - 9 x 800m with 90 seconds rest. The goal was to start at 10k pace and work down to 5k pace. Fisher went on to finish 5th at the NCAA National XC Championships while McGorty finished 24th. Stanford finished 2nd as a team. Note how under control they stay.