I upped my mileage and started lifting this fall, and my times have been dropping. I ran a 10 mile threshold run yesterday averaging 5:21 per mile and I never felt like I was straining. Hell, I felt like I could have run the last mile 20-30 seconds faster if I had to. I figure another few months of this and I'll be ready for some PRs, but I'm wondering by how much. A 10 mile threshold is a lot different from a 3000m. I ran 8:32 last year. What should I aim for this year given my improved fitness?