How Much Speedwork for Marathon Runners?
By Karen Hancock
From New Years Day there remain 15 weeks to the London marathon, fewer until Paris and more until Prague. Some serpies have shown me their training plans. I am writing this because I have noticed a common, and somewhat baffling, tendency to include a weekly track session in some plans, even from the beginning of January. I suspect this is force of habit, rather than the result of careful analysis. The simple fact is those of you embarking on your first marathon – especially those aiming for sub 3 hours, from a background of 5k and 10k races – have not developed your aerobic systems as well as you have developed your speed. You can increase your speed very quickly; it takes many years to fully develop your aerobic system. That's why I can run faster at the marathon than quite a few men who run faster than I do over 5k and 10k: I've been running for more than 20 years.
My advice is to think of this phase as stamina-building. Technically, this is a meso-cycle lasting 6 weeks, and culminating in the Watford 1/2 marathon perhaps. I would not include any intensive speedwork, especially track sessions, in your schedule until about 6-9 weeks before your marathon. At that point, you should begin the sharpening phase (or meso-cycle) of your training. Speedwork should continue (at reduced volume) into the taper meso-cycle, which lasts 3 weeks.
Why do I say this?
The marathon is an aerobic event
Essentially, you will need to be running for nearly 3-4 hours at well below your maximum speed, below even your lactate threshold: you need to train your body to resist the development of fatigue, not train it to run flat-out for 3 kilometres (which would give an indication of your VO2 max) or 15k (close to your lactate threshold). If it's your first marathon, you will be lacking the base of endurance which is necessary to running it well, unless you have been doing long runs of at least 15-16 miles every week throughout the year (as recommended by Bud Baldaro, Eamonn Martin, Arthur Lydiard and many others). If you haven't, then you should be mileage-building now (but increasing the totals sensibly of course). If you do a weekly track session, then you are sacrificing an opportunity to add some more miles at more useful paces to your weekly total, and if you do it on a Tuesday, you will compromise the quality (and possibly length) of your marathon-paced run on Wednesday, assuming that's when you've scheduled it.
All training has an opportunity-cost (in other words, you are sacrificing an alternative, possibly more useful session), and at the moment your priority is building endurance. And if it's not your first marathon, all those miles you've been doing over the last 4-5 years have contributed to your stamina, and will help you to continue to improve at the marathon for the first few years of training for them – possibly longer (ask Dave McGregor, whom I think said it took him 12 years to set a new marathon pb!).
You only need 6-8 weeks' intensive (faster) training on top of a solid endurance base to reach your peak
Tim Noakes cites many authorities for this finding, including some well-known marathoners (such as Derek Clayton and Ron Hill) and coaches (e.g. Lydiard, Martin and Coe, Daniels and of course Noakes himself). There are also scientific studies which demonstrate that large improvements in performance can be achieved quite dramatically by adding as few as 6-8 sessions of high-intensity interval training over as little as 3-4 weeks.
Too much faster training is bad for you
It is very taxing, increases the risk of injury and reduces resistance to infection. Therefore, sharpening training (which would include speedwork) can't be maintained for more than about 8-12 weeks. After that, performances start to tail off and the risk of over-training rises. Mentally, speed-work is harder than endurance training, and you cannot sustain the freshness you need to look forward to it, if you are doing speed-work week in, week out, all year round.
Speedwork is particularly risky for those of us over 40, who are less flexible, more prone to injury and take longer to recover from them.
You're probably already doing some speedwork, even before counting the track sessions
Hill sessions, cross-country races of around 5k and fartlek sessions all count as speed-work since you run them at close to your VO2 max levels. If you're already doing these, then you certainly don't also need track sessions at this stage.
What sort of speedwork is best, when the time is right?
Noakes' summary of the scientific and anecdotal evidence is that hill running (of course!) and fast, long repetitions of 800m - 1600m are the most beneficial forms of speed training for marathon runners. Note that the long reps don't have to be carried out a track, although the track does provide an exact measure of distance, and the presence of a coach to monitor and advise you.
What about Yasso 800s?
Some of you will have read about Yasso 800s – the idea popularised by "Runner's World" that if you can run 10x 800m in 3:00 with 3 minutes recovery between, each you can do a sub-3:00 marathon; if in 3:30 you can do a 3:30 marathon, and so on. I am extremely sceptical.
First, 800s are OK as a repetition length in speedwork for marathoners, but the recoveries are too long and the session is therfore not challenging enough. If you want to do 800s in 3 minutes each, see if you can do 10 of them with a 1 minute or 90 second recovery. That will be better for your speed-endurance. But don't do 800s every week. Do 1000s, Mile repetitions and 1600s for a change.
Second, don't believe the hype about the predictive powers of Yasso 800s. They are scientifically unvalidated. To predict your marathon potential, rely on your performance at half-marathon or 10k races: the formulae used have been statistically tested for predictive power (see for example: www.runningforfitness.org)
If you must do track work or other high-intensity intervals, save it for the next phase of your training. I want you to succeed in your marathon ambitions, not to display potential at shorter distances and then fail! Now is the time to work on your endurance, your marathon-paced runs and a wee bit of lactate threshold-moving tempo running.
UK Athletics Level 2 Coach ("Endurance" and "Children in Athletics")