We all know our long runs are the meat of any marathon training program; the most basic training programs essentially consist of base milage and a long run on the weekend. However, I've recently put a twist on my long runs. The idea originally came from Hal Higdon: he suggests doing a 3:1 workout every few weeks when feeling good. The idea is simple, run the first 75% easy then push for the remainder of the run.
I first read about this while training for my first marathon last year, and simply discarded it as crazy talk; running fast at the end of a 20 miler?! However, this time around my training is more about speed, and when I read similar advice recently (I believe in Runners World, although I'm not positive) I decided to give it a shot at the end of a long run where I'm feeling fresh.
My strategy is to do the majority of my run at a relaxed pace, about a minute per mile slower than goal race pace. If I have to run slower to run with a group, this is not a problem for me. Slow long runs are better because you will be on your feet for a longer time, thus increasing your endurance; although going too slow can result in poor form, too slow being more than 20% slower than goal pace (Advanced Marathoning by Pete Pfitzinger).
However when training with a specific time goal, one lingering question that was always on my mind is: Sure, I can do a tempo run at race pace, but can I hit it and hold it after 15 miles? To answer this question, I started running race pace for the last 25% of my long runs on days I'm feeling good at the end.
Although the experts may argue the physiological advantages of this aren't there, I can vouch for the psychological gains! The confidence this instills is tremendous, since you're proving there is still some spring left in your step at the end of a long run. I am much more confident in my ability to break three hours at Chicago after my last few long runs. Also, since I only ran hard for the last five miles I'm not as drained as I would be if I ran quick for the entire run; I will be ready to run hard again by Tuesday, as scheduled.
Please let me know if you've had any experience with this technique, or are planning to give it a shot! Make sure you let me know how it goes!