You are correct about training for the right activity. When we officiate football we run, but in short sprints mostly, with occassional 80-100 yard sprints. My trainer advised me to train aerobically on low impact equipment to protect my knees, and then go run a series of sprints on the field. She suggested running a series of 20, 40 and 60 yard sprints in sets of 5 or 10. She also advised orking on core body muscles (abs) and doing agility drills will hope with change of direction moves we must be ready for. She put together a progrqam for our association and I'll include the link here to 2 pdf files you could use and share.
http://www.nkoafootball.org/guests/f...nditioning.htm