Hi, I am a rising junior who wishes to run under 16:00 next year in XC. I ran 4:36 and 9:57 this season, so I know I can break 16:00, but I am looking long-term in the future and I think that I need better 400/800 speed to be competitive in track later on. I could probably run about 58.high in the 400 now, so is there any way I can get under 56 without wrecking my endurance too much? Lifting, hills, etc. is what I was thinking, but I don't know how to do it properly.
Thanks, and specific advice is much appreciated.