Running Volume vs Intensity Revisited


At the end of last year I wrote about Running Volume vs Intensity, with a short analysis of my results from following both approaches.  Whilst people can argue that one approach may be more suitable for a certain type of athlete than the other, ultimately, the best training plan will incorporate both elements.  There's no hidden secret to success, it just takes hard work on a consistent basis.  
Within the last 7 weeks my weekly mileage has been very consistent at around 40 miles.  That's not a lot of mileage, so if I was only logging slow aerobic miles then my progress would be sow and quick to stagnate.  However, within this time period I have increased the amount of high intensity miles each week, sticking to the principle of progressive overload.  I've done a range of different training sessions, including 400 and 800m repeats at the track, mile repeats within the long run, tempo runs, steady runs and recovery jogs.  The diagram below illustrates how my time has been spent running at a range of paces, rather than sticking to one pace as I've done in the past.
Speed Distribution Last 28 Days
(Click to Enlarge)
So what have the results been?  After just 5 weeks of structured run training, I improved my 5k time by 19 seconds, beating my previous best that I set in 2009. I'm in the best run shape of my life and enjoying the training.  That's not to say that it's not tough.  In the last 4 weeks especially, I've never felt so tired.  Recovery has taken on a new meaning, religiously supplementing with Extreme Endurance, using compression, stretching, napping and eating the right foods at the right times have become more important than ever.  
One potential issue with running intensity is the increased possibility of injury.  I'm fortunate that I have a few fctors in my favour, namely youth and 5 years of running base where I've logged miles consistently with little time off.  This has been the foundation that has allowed me to increase the intensity and (touch wood) stay injury free.  I also ensure that I stretch following every run session, which I've found helps with recovery.
In the end, there's no substitute for mileage, and you won't find many of the best Ironman runners doing minimal mileage.  40 miles/week cut it for much longer.  No matter how intense your sessions or how fast you run over distances up to 1.5k, 5k or even 10k, without the necessary training to prepare you for the marathon distance, you won't reach your potential.  The real challenge is getting the right balance between volume and intensity, as well as fitting in the sessions around swim and bike training.