Poor Pace Judgement: The Runner’s Kryptonite

It’s the single biggest decider between you having a good day on November 3 and having a terrible day. It can put you in hospital, smack a DNF next to your name, or simply prevent you from expressing your true potential as a runner.


If you get anything from this blog, get this, in fact, write it on your hand on race day: aim to run even or slightly negative splits. And here are six reasons why:

1) It works for the pros

Most world records over middle and long distances are set by running even splits. Kenyan Wilson Kipsang recently broke the marathon world record when he ran a mind-boggling 2:03:23 in Berlin. His last kilometre was one of his fastest and his 5k splits were all within 25 seconds of each other. So that’s a maximum average variation of just 5 seconds per kilometre, whereas last year at the Auckland Marathon many finishers slowed up by 90 seconds or more per kilometre.

2) It also works for the Everyday Joes

When I ran my most recent half marathon PB I was running solo from the gun. It was a smaller off-road event so I just had the forest, the kilometre markers, and my watch for company. I clocked off 3:30-kilometre after 3:30-kilometre.

I got tired but only really started to fatigue fully in the final 2km. Here I could sense the finish line coming so was actually able to increase my speed for a final burst into the finish. I was exhausted on the finish line, but that’s where you want to be exhausted, not at the halfway point because of poor pace judgement early on.

3) The other option often ends in ED

A few months after this half marathon PB I ran my first marathon. I was in good shape but the race was in Chicago and it was hot, twenty-eight degrees hot. I knew I should have adjusted my pacing goal but the huge crowds and the ease at which I floated through the first 10k clouded my judgement.

At about 25k, the heat really got to me and the wheels fell off, being replaced by what felt like increasingly larger lead bricks. As I slowed, other runners whizzed by; each lost place grinding down my determination to go on. I stumbled across the line for a PB (as it was my first marathon) but soon found myself in an ambulance bound for a Chicago hospital’s emergency department. Five hours later, after a few bags of saline fluid, several blood tests, and a $4000 bill I was free to run (yes, run-I had no wallet, phone, or idea where in Chicago the hospital was) back to my hotel.

What went wrong? I ran about 10 seconds per kilometre too fast for the first 15km, just 10 seconds, that’s all it takes sometimes. This created excessive fatigue that I had to carry around with me for the next 27km. The extra fatigue not only destroyed my time goals for the race, but also put my health at risk.

4) Running style suffers

Running form plays a huge part in your efficiency. However, when you get the pacing wrong and get fatigued, your running rhythm and style are often the first things to go downhill. This makes it harder to run, which adds to the fatigue and makes you run slower, which then gives your worse form. It’s a vicious cycle.

5) It’s a mental game

Most of us have a competitive streak. And even if yours is buried somewhere deep, you can be sure it will start to surface if you’ve paced your race well and begin passing those who haven’t. The adrenalin kicks in with every competitor that you reel in and leave in your wake. Your inner Usain Bolt takes over and you may even find yourself accelerating while everyone else is going backwards. It’s a great feeling and will leave you hungry for more.

6) Last year’s results speak volumes

I’ve analysed the results for various finishers of last year’s Auckland Marathon, calculating the difference in their splits from the first half to the second half (check out the fascinating results here).

The male and female winners both had a very slight positive split (11sec and 24sec respectively), meaning they slowed up a little in the final half, probably to enjoy the moment and wave to the crowd. Ultimately, their even pacing shows how experienced they are at judging their current fitness, setting realistic pace goals, and sticking to them.

However, when I looked down the list of 38 results that I analysed (including a good cross section of finishers from fastest to slowest), only five of the runners managed negative splits. The large majority slowed up significantly and, typically, the slower the marathon the worse the positive split.

In many major marathons it’s not uncommon to see split differentials of 40 minutes or more at the back of the race. This represents a whopping two-minute per kilometre slowing in average pace (which is the equivalent of dropping from 15kph down to 10kph). So there are huge gains to be made for most of the field, particularly those running five hours or more, simply by getting the pacing right.

Tips for setting a pace goal

  • Analyse the speeds of your longest runs.
  • Do a race (5-10k is perfect) about a week or two before the event and use a website like mcmillanrunning.com to estimate your projected half or marathon time.
  • Be aware that online calculators make generalisations, so personalise your projected time by tempering it with how you feel on your longest runs (i.e. could you hold that same pace till the end of the race?).
  • Create a realistic time goal that errs on the conservative. Also adjust the time to be slower closer to the day if wind and/or heat are forecast.
  • Get outside advice by finding a coach who can help you calculate your time goal in an objective way (contact me if you want help here).

Applying your time goal

  • Break this time into individual 5km splits and commit them to memory.
  • Know what pace per kilometre this time goal represents.
  • Go no faster than this pace for the first 32km (or 13km in the half).
  • Run a practice run one week out from race day at this same pace for just 5km and during this run also practice drinking on the run to simulate race day.
  • Use an accurate GPS watch as a guide and make sure it’s well charged the night before and that you’ve connected it to a satellite well before race start.
  • Finally, enjoy the feeling of finishing strong and passing by others who ignored every runner’s kryptonite and started too fast.

This article is an entry by Hayden Shearman on his training blog at Stuff.co.nz (published16 October). 

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