The 20-miler

I thought I'd share my controversial views on 20-milers. I say controversial, as what I'm about to say seems to offend some people, but it's my blog and I'll say what I want. So here goes:
Do not race 20-milers!

I need to explain that one a bit of course, so first of all let me say that this is very much in the context of marathon training. I should also say that I'm not suggesting you don't do 20-mile races - they are excellent training. I should also say that I have done more than a dozen 20-mile races, but the closest I've come to racing one flat out was last year at Worthing where I jogged the first 5 miles, then picked the pace up and ran much of the remainder at marathon pace, finishing in 2:31:33 - an average pace of 7:33/mile, which was actually faster than the pace I subsequently ran the (very hot) London Marathon in! That was a measured effort and I recovered well for London 3 weeks later - it was the heat that did me in on the day, or so I believe - but this hints at the problems of using 20-mile races as marathon training.

What I mean by racing a 20-miler is putting maximum effort into your run to achieve the best time you can. I have never done this, I confess, but I know many people who have regretted racing 20 (some deny the 20 caused the problem but in the context of their training I believe it was a, or even the, major factor). The problem is simply the amount of recovery needed afterwards. It can take a full 3 weeks to recover from 20 miles of maximum effort, and that ignores the effect of whatever training you choose to do subsequently.

Most people are pushing it quite hard in the run up to a marathon. 20-mile training runs are all part of the formula, and very necessary too, but there are much better ways to tackle the 20-mile training run than running it flat out. The 20-miler should be one component of a balanced training program, allowing sufficient recovery to perform your interval sessions and tempo runs. Jog a 20-miler and you should be feeling fairly fresh 2 days later for your tempo run or your mile reps. Race a 20-miler though, and the following week you are feeling jaded and unable to put any effort into the training. You try harder and push all you can to achieve the right paces but just can't manage it. Of course that's the optimistic outlook. At worst you push too hard, get ill or injured and miss the marathon completely.

20-mile races, flat out, are hard. It should be fairly evident that their impact is almost as great as that of a marathon. One unseen risk is that your immune system pretty much collapses for 24 hours afterwards, laying you wide open to whatever bugs are around. You push on with your training and a week or 2 later you are laid up in bed with flu symptoms.

Even running a 20-mile race at marathon pace is hard. It's 20/26th of the effort of a marathon: 77% of a marathon is very tough!

20-mile races, as training, are however very useful. They are brilliant practise for getting your fuelling and hydration strategy right. What better way to do a training run than in company with others and having drinks laid on for you without the need to run with a bottle belt or camelbak? You need to view them as training runs though and run them sensibly.

Early in your marathon program I'd suggest just jogging them. Take them nice and easy and don't worry about the clock, other than to make sure you are at least a minute/mile slower than your marathon pace. There is a school of thought that says you shouldn't do your long runs too slowly as they are not specific enough. While I can see that it might come as a bit of a shock doing 26.2 miles at 7:30/mile when you've only run at 11:00/mile in training, as long as you have been doing tempo runs, and you do include some faster long runs then the occasional reeeeaaally slow run won't do any harm. Generally try to keep them between 1 and 2 minutes/mile slower than marathon pace.

Later in your program, with maybe 6 weeks to go to the marathon, try adding a fast finish to the run. Jog the first 15 miles and then try lifting the pace up to marathon pace for the last 5 miles. Make sure you carbo-load for the race as you'll find this very tough if you're low on fuel.

The hardest I reckon you should run is 15 miles of marathon effort (although I personally think that 10 miles of marathon effort is sufficient). Try this 3 weeks out, no closer. Jog the first 5 miles and then pick up the pace for the last 15. Remember that 15 miles of marathon pace is a very hard training run. Don't do this closer than 3 weeks to the marathon. Give yourself a day or 2 of recovery and you should be OK but look for signs of fatigue. If you attempt a 20-miler only 2 weeks out then jog it - don't attempt a large amount of marathon pace running so close to the marathon.

Of course people will still want to race a 20-miler, but if you absolutely must then I'd say: don't try this within a month of the marathon, consider taking several days off afterwards, and cut right back on the training afterwards with little or no speedwork for a week or 2. Bear in mind the context in which you do the race. How much other racing have you done? What is your training load? Remember that the marathon is (probably) your target. If the 20-miler is your target though, then good luck to you - you obviously won't mind if you don't do that well in the marathon.

It's amazing how heated on-line discussions can get when I say "Don't race 20-milers", but hopefully I've presented a balanced view on the topic.