At my school we run a lot and do many sprints.
We do circuit type workouts. Sprint 30 yards do 5 squat jumps, sprint backwards. Rest. Repeat 3 times. Then instead of squat jumps we do explosive split squat jumps. Repeat 3 times. Then 4 60 yard sprints, 4 40yards and 4 20 yards. We do mostly body weight workouts on the field. Usually we sprint one day and long distance the next day 6 days a week.
Any other questions or ideas I can hook you up.
Oh and we do core work after running