... Background: I'm 29. ... Starting Training Paces (as of 1/1/2008): LHR training pace (hour runs): 14:49 LHR training pace (runs > 90 mins): 16:00 ... Current Training Paces (as of 4/10): LHR training pace (hour runs): 12:24 LHR training pace (runs > 90 mins): 12:37 I have been training using an interval method, where I run until my HR hits 150 bpm, then slow down and/or walk until my HR hits 130 bpm. Almost always run for 1 hour, but have long runs where I run for 90 minutes or more once every week or two. ... I feel like my 5k time isn't going to improve without some kind of faster work once in a while. I'm considering the following plan: 1) Continue current LHR training, continuing to build mileage to 25-30 mpw. 2) Instead of running LHR every run, once per week substitute a 4-5 mile tempo run or a 5k race. Thoughts?