I did a 400 session alone(and in the cold) today since one of my resolutions was to break 60 in 2017. Previous best was 70. In the video I go out the first 100 in 13 high(pr was 14 from a month ago.) 200 at about 29-30ish, and crumble to 35-36 for the last 200. I basically hit two pr's in one race. I'm doing easy runs and tempos @15-20mpw but I am improving my times dramatically. I'm 14 and the only change in my training has been that I'm doing more tempo intervals like 15x400s @tempo pace with 1 min jog rest. Just seems like interval training is what I best adapt to(maybe)?