Day 12: day off

No run today, but wanted to lay out in more detail how I will tackle the sub-5 quest. There are really two elements to getting there - an aerobic piece and an anaerobic piece. A few months back, I read an article by a man named Frank Horwill. He is a running coach in the UK, and has coached five sub-4 minute milers in his career. The article discusses training for a sub-4 mile (uhh, not currently my goal), but I think the principles apply equally well here. The full article is here (http://www.serpentine.org.uk/advice/coach/fh15.php), but my main takeaway is that he sees the mile as 50% aerobic, 50% anaerobic. By comparison, a 100m sprint is 100% anaerobic, while a marathon is close to 100% aerobic.

The reason this struck me is that I always knew intervals and speed work were important to improving my mile times, but I thought this was simply a matter of getting my legs used to running faster. The real reason to do intervals is to build up anaerobic capacity - to improve the body's ability to work with less oxygen than it can take in.

At the same time, the aerobic training is intended to raise the body's oxygen intake capacity (VO2 max). Interestingly, he says that longer, half-marathon pace runs just 'get in the way'. Of course, he still advises running that distance, but at a pace only 1 minute slower than best mile pace. Ok, that would kill me right now, but maybe that's only for four-minute milers.

His training regime includes three aerobic and three anaerobic (intervals) workouts per week. In phase I of my training, I plan to do only one or two interval sessions per week, but I will increase this if/when my times come down. The anaerobic piece is going to become more and more important as the 5 minute barrier approaches.