Schrodingers 800. It's both. If you're a sprinter you'll think it's a distance event. If you're a distance runner you'll think it's a sprint. I was a sprinter who moved up and in college was fully in 800m training. Every race I ran I relied on my speed. The opening 400 felt like a jog. To me it felt like I was running a distance event because of how I needed to pace it. But even then, I deep down felt it was more a sprint. How much mileage you do in practice does almost nothing for your 800 time. You can run it off speed alone and speed is required to run it fast. There are guys making it to ncaas in the 10k or xc who cannot break 155. Every single guy at ncaas in the 400 could break 152 with no additional training