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Aiming for sub-40

October 13, 2009

Back when I started training in February, I had set my sights on completing the Oxford Town & Gown 10km race in 45 minutes. As luck would turn out, my official race time was 44:59, but my chip time was over a minute faster. Now, with several races under my belt and a more coordinated training programme, I’m close to breaking through the 40-minute threshold.

It’s time to see if I can break through the barrier before the end of the year.

Talk to club runners and there’s something about doing a 40 minute 10km. Sure, there will always be the elite pack of runners who knock out the distance in close to 30 minutes, but the majority of the good runners will hold 40 minutes as a difficult-but-rewarding goal.

Running a 10km in exactly 40 minutes means that you need to run 10 consecutive kilometers in 4 minutes each at most. Simple? Of course, it’s more complex than that. I recently made a slightly facetious comment to a colleague that I’d picked a one-dimensional sport. This isn’t the case, but it’s easy to diagnose it as being so from the outside – after all, you’re just running as fast as you can for as long as you can, right?


I can’t claim to be any kind of authority on race pacing. After all, I’ve made my fair share of mistakes – even if they ultimately resulted in PBs. However, there are some key things you need to think about in a race:

  1. The first kilometer is where you set the tone of your race. Start slowly (not necessarily a bad tactic if you’re aiming to build speed over consecutive kilometers) and you spend more time in the crush of the pack – this means you spend more time and energy darting between runners. Start too quickly and you risk being pulled along at an unsustainable pace.
  2. The 60–80% kilometers (where you are between 60 and  80% of the way through the race) are the most mentally grueling. If you have started fast, it’s probably around this time that you stop overtaking other runners or may even be overtaken yourself. If you set off slow, you may well still be overtaking other runners as you build speed, but you will now be operating at very close to your top speed for the distance. At this stage, you need to keep up the pace, and it’s traditionally at this stage that my split times start to flag.
  3. The end zone – or the last kilometer – is where you need to pick up your game, no matter how tired you’re feeling. However, you can’t expect to sprint 1000 meters and you often see people misjudging their finishing pace and slowing before the line as their muscles fill with lactic acid. You need to build your pace, stretch out your strides, use your arms a bit more and pick your moment to go hell for leather. It’s all about knowing your limits.

In order to run a sub-40 10km, I need to improve my consistency – for example, at Blenheim my splits varied from 4:47 to 3:21. Running this distance, you are operating more or less at your aerobic threshold – your pace is a delicate balance between running fast and preventing your body from building up waste products that will give you cramp. Realistically, to give myself some leeway, I’m going to need to target 3:50 splits.

Course profile

Know your enemy – although you shouldn’t rule out running fast times on challenging courses, a few hills, sections off road and uneven surfaces all make a PB less likely. So, if  you are aiming for a PB, you need to pick your course to give you the best chance of success.

Although I’m not ruling out adding a couple of extra races to my schedule, my forthcoming races are as follows:

Frieth Hilly 10k – a challenging course with sections off road and steep hills, knocking 35 seconds off my current PB at this race is highly unlikely.

Eynsham 10k – fast and flat, run entirely on tarmac and advertised as having PB potential, it has chip timing too (in case I need to cite a chip time rather than a race time).

Andy Reading Bicester 10k – another fast and flat urban race, it’s in early December, so the weather may affect performance if it is particularly inclement or cold.

Poole Round the Lakes 10k – a Boxing Day race on flat tarmac, although potential may be limited by the weather and any lingering indigestion from the previous day’s festivities!


As one final caveat to achieving this goal, I need to get the right mix of training. In my gradual taper for the Paris Marathon (although it’s filling up fast, so I need to get my entry in), I’ve added a 20.5km (12.5 mile) run on Sundays, which I’ve been completing in around 90 minutes. This helps me in the difficult 60–80% zone by building my stamina – and giving me the mental advantage of knowing that I’ve run double the distance before.

I need to do some speed work, though, as I’m aware that my stride should be longer and that I’m not using the best form at times. I could also benefit from increasing my lactate threshold.

So, work to do, but the goal is within sight – and, more importantly, achievable before the turn of the year.

One Comment leave one →
  1. Steve Taylor permalink
    October 15, 2009 10:48 am

    Hi Lewis

    Really like the blog. I am a co-organiser of the Frieth Hilly 10K and would like to wish you all the best for the race on Sunday. Weather forecast is good and the course is looking beautiful. If you would like a tip for the race – leave a bit in the tank for the final 400m – it is an uphill stretch back into the village and can be painful for those not expecting it! Many places are won and lost on that hill.

    Best of luck for the race and thank you for entering.

    Steve Taylor
    Head Marshal – Frieth Hilly 10K

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