I've targeted the Kingston marathon in October to get a new PB (target sub-3.30, current best 3.38 at Edinburgh in 2014). Over each of the next 16 weeks, I'll be addressing a different aspect of marathon training. Follow me on my journey and tell me about yours!
When you have a big race coming up, putting a practice race or two in your calendar is not only really helpful, it's also fun and can provide a great confidence boost. The key is to pick races that a) are relevant to your goal race and b) are timely.
This may seem obvious but picking the right race in which to practice racing is crucial if you're going to learn anything useful. Doing a 10k in the lead-up to your marathon probably won't do you any harm, but given you'll be running at a different pace and are unlikely to fuel in the same way as for 26.2 miles, there's a limit to how much you can glean. Sure, it might give you a warm feeling inside if you get a PB but if that's not the main aim, what's the point?
It's far more useful to select a half marathon, or better still, a 20-mile race as a practice run. These distances will provide you with the opportunity to run at a pace closer to your target marathon pace, try out your race day kit, and understand how your body reacts to water, gels and food over the longer distances. Yes, you can (and probably should) run 20 miles in training, but race conditions are different.
You need to travel to the start. You might need to pick up your race number or drop off a bag. You may well need to use the toilet, and there will definitely be queues. Then you will almost certainly have to stand around waiting for the race to begin. These are all things that simply aren't an issue when you're setting off on a training run from home. So practice them. Make sure you know how it feels so when the big day arrives there are no surprises and you feel comfortable in a race environment.
The other good thing about a race is that you can't move it. Sometimes it's tempting to postpone your long training run because it's raining. But what if you don't ever train in the rain and it's raining on race day? Being prepared is to be ready.
If you're the sort of person who loves to race, you might well have a race in your calendar every other week. In which case, race day practice is not so necessary. However, if you want to perform to the best of your ability in your goal race, it's best to time your practice races to fit in with your training plan. Your plan - if it's any good - should be structured so that you have peak training weeks and easier weeks, to enable your body to recover from the hard work you've been putting in. It's important to time your race so as not to negatively impact the bigger picture.
Depending on your build-up to the race, I would suggest doing nothing too strenuous within two weeks of race day. Certainly no more than 20 miles (unless you're very used to running that sort of distance regularly), and while shorter races can be useful as a 'tune up', I'd recommend not going at 100% in them. The chances of picking up an injury are too high and outweigh any possible joy gained from a PB.
There are as many ways to successfully fit in practice races before your target marathon as there are people, because we're all unique and react differently to situations and training stimuli. Last year, one of my main aims was to get a PB at the Edinburgh marathon at the end of May. I very much doubt you'll find "run a 50-mile race 6 weeks before your race" in any training plans but that's what I did and still managed a huge PB. I'm not saying that's the answer, far from it, but it's not worth worrying too much about the detail if you've put in the right kind of training.
For various reasons, I haven't been able to do that in the last few months. But as it's been over four month since my last race, I'm still going to practice the art of racing over the coming weeks, with the Wimbledon Common 10k this Saturday and the Ealing Half Marathon a week on Sunday. After that I'll be a lot better placed to know how my marathon will play out...