I'm a college sophomore who's been trying to walk-on at my D-1 college for a little while now. The coaches know who I am but still want me to drop my times. The time I'm aspiring to hit (they've given me a number of times I should hit) is a sub 4:25 mile. On October 1st I ran a a new PR of 15:56 for the 5k. My 4 mile PR is 21:32, my 5 mile PR is 27:49, which I ran in an admittedly less-than-great performance. During my freshmen year I ran a 4:41 mile in the winter and a 4:39 in the spring. Based on my times I'm guessing I'm low 4:30's currently in the mile. The next time I plan to race is at the BU mini meets in December where I would like to go sub 4:25. During my freshmen year, I ran a PR in the 5k of 16:36 right around the time I ran my 4:41. Do you guys have any tips to help me improve my speed especially in reference to transitioning to 70 miles a week to a more quality track work-like week?