There is a lot of literature and theories out there regarding the length and speed of your long run. Everyone seems to have their opinions and I think a lot of it may depend upon the individual. But the way I’ve been doing them over the past couple years may be sub-optimizing my marathon times.
I’m a pretty decent half-marathoner with a recent personal best of 1 hour and 25 minutes. If you plug that time into any marathon prediction calculator, it says I should be capable of running a 3 hour marathon. However, I’ve fallen far short of this time after time by a dozen or more minutes.
So what gives? How come I’m not living up to my potential? My theory is two-fold. First, I was not doing enough weekly mileage to improve my glycogen storage and fat utilization – which I’ll discuss in a future post. And second, my long runs were too long and I was running them too fast. So basically, when race day came around, my gas tank wasn’t large enough and I probably left my best running on the practice field.
I came across the table below from the book Advanced Marathoning. They recommended your longest run be no more than 22 miles and the pace be gradually ratcheted up, with the first 5 miles as a warm-up, the middle miles at 20% slower than planned marathon pace, and the last 5 miles 10% slower than planned marathon pace.
During this recent marathon season, many of my long runs exceeded 22 miles. In fact, I went as long as 28 miles during one long run in preparation for the Tokyo Marathon. Also, I usually only warmed up for a mile before I started pushing the pace and would often run the last 5 miles faster than my goal marathon pace. So instead of running 8:24/mile ~ 7:42/mile as suggested by the chart above, I was consistently averaging between 6:45 ~ 7:30 per mile the entire long run. Looking back, assuming the chart above is ideal, it’s no wonder that come race day I never lived up to my expectations.
As insightful as this may be, it will take some discipline to adhere to the chart above. I tend to run based upon how I feel and probably much to my detriment, holding back has been something I struggle with. My mind works like this — If I’m not hurting to some degree, or if it feels too easy, then I’m not getting the training benefits. But I’m also constantly reminded that successfully training for a marathon is a bit counter-intuitive, so I’m willing to give this theory a try.