Getting your pace right makes for a much happier marathon experience.

Pacing a Marathon – Planning Your Race and Getting it Right on the Day!

The marathon is a very individual thing.  You have to run your own race.  I hope this article will help you plan your race and give you a better chance of getting things right on the day.  I have certainly learnt lessons from making plenty of mistakes. 

The first thing is that it is no easy feet to get the pace right.  Of my 11 marathons (ruling out my first two which were 10 years apart when I had very little knowledge of the distance), despite being pleased with the majority of finish times, I can say that I have only paced it well on two occasions.  Interestingly, both were in Paris and both resulted in personal best performances.


Before we can get the pace right on the day, we need to decide on what our target time will be.  There are different ways of estimating a target time, but in my experience, it is best to be conservative.  My current Garmin prediction is 2:26 and some change, a full 22 minutes faster than I have ever run the distance before.  Much as I would love to think it, that is simply not realistic. 

My most recent race was a 1:16:36 half marathon.  It came in September last year in the build up to a Marathon PB attempt.  I was due to run an October marathon and would have used this time to help make a pacing decision for the race.  Without dwelling on it too much, injury struck a couple of weeks before Amsterdam, and the result was two months with no running, followed by two months building back up.  I am delighted to be back and feeling fit – but the reality is that if I were to run a half marathon, I would be unlikely to go close to a PB.  I am building back up.  Best not use my most recent race to set a target marathon time on this occasion.

So, now a combination of experience and training are helping me set my London 2019 target.  My PB pace is 4 minutes per kilometre.  I just haven’t done enough running at that pace or significantly faster in training to warrant a PB attempt.  That said, I have been running comfortably for long periods (on legs tired from training), at 4:05 to 4:10/km pace.  I have run a 2 hour 58 minute marathon of significantly less training than I have managed this time around.  So, my window is looking like somewhere between 2:50 and 2:55 for the marathon.  The experienced side of me is planning on 2:55, with the potential to speed up if (and it’s a big “if”) I am in good shape in the final 10k.

A quick summary – using race time predictors can be really useful, but can be dangerous as a stand-alone tool.  Best to use a combination of experience (if you have done the distance before), previous races if they have been done recently, and what is a sustainably fast speed during your tempo workouts in training in conjunction with race calculators.  The reason I am wary about going on purely race time predictors is because it does not consider the training you have done.  You may be a very accomplished half marathon runner with some very good times over the distance.  And while that is a good thing, if you do not build the endurance to run double that distance, your HM time is almost irrelevant.  Race predictors assume you have done the training and are ready to go.  As a very experienced runner said to me recently (when I was discussing fuelling strategies):

“Gels are great and you need to fuel.  But if you haven’t done the long training runs and built the endurance, nothing will fill the void!”

Long runs are vital to success!

It is the final 12km that have humbled me so many times.  As I said at the start of the article, I have only sustained my speed through this section of the course on two occasions.  That means that in no fewer than nine marathons have I slowed down significantly in the final quarter.


  1. Chasing PBs – To give myself a bit of credit one of the reasons has been that I have tried to go for big PBs.  When I first broke 3 hours in 2013 (2:56) I immediately started pushing to break to 2:50. It is not easy to take big chunks out of PBs and there must be an acceptance that it won’t always happen.  When you push your limits you risk failing, and in the marathon, that probably means missing your time by quite large chunks.
  2. Naivety and Over Excitement!  This has played a key part in my final 10k woes.  For example, in London 2015 I planned to run 2:48. Training had gone well.  I felt awesome in the week leading up.  The plan was an even paced race with two half marathons of 1:24. But the problem was I felt so good.  4min/km pace was just so easy.  Surely that meant I had to run faster and reset my goals on race day?  I also have a long term goal of running sub 2:45 in the marathon.  It was not a goal that day, but I felt so good, why wait?  Why not tick the sub 2:45 off today?  It’s amazing what you can convince yourself of during the excitement of the early stages of a long race.  You know what’s coming…I increased speed cruising through half way in 1:21 with my average pace in the low 3:50s/km.  At the time it was my second fastest half marathon ever.  It felt so easy until about 15 miles (and that is early) when the legs started nip.  The result was a painful final 10km and a much slower second half dealing with cramps in places I didn’t even know existed.  Somehow, I made it round the 2nd half in 1:29 – but that is a full 5 minutes slower than the plan.  It was still a PB at the time of 2:50, but it felt quite unfulfilling in many ways because of the stop start nature of the final miles.  I had prepared to run 2:48. That pace was comfortable in training.  That is what I was conditioned for.  I had not prepared to run a 2:42 marathon, so in reality it is no surprise that things got tough.  Training conditions the body for certain distances and certain speeds.  Change the speed on race day and expect the distance to much tougher than it might otherwise have been – and this is something we all have in common.  It does not matter what speed you are trying to run at or your target time.  Your speed and conditioning are specific to you.  That might mean you are trying to break 2:30, or it might mean that you are aiming for a time of 5 hours – both are amazing.  The marathon is an individual challenge run for many different reasons.  Only a very small number compete for medals.  No matter what your reason for running, what your target time may be, it is vital not go out too quickly.  Stick to your plan!


Assuming the things you can’t control like the weather are all in good order.  There are two strategies that give you the best chance of success:

Even Pace – once you have selected an appropriate target time, set out your splits for each kilometre or mile, and know what you need to pass each 10km section in.  Then no matter how good you feel – stick to it.  It will be easy in the early stages – but keep your discipline.  Spread your effort over the full distance.  It gets harder later on!

Negative Splits – the preferred option of the elites is to run the 2nd half of the race slightly faster.  Why?  Because it means they have saved as much energy as possible for the final miles when the pace is hardest to sustain.  When energy is at a premium and the muscles are at their most tired, holding something back for the final stages is the way they like to do it.  A key reason for this is because they may need to accelerate to win races and break the will of those around them.  Eliud Kipchoge sums this up brilliantly when he said:

“In the marathon, the first half is just a normal run.  At 15 kilometres, 20 kilometres, everybody is still going to be there.  Where the marathon starts is 30 kilometres.  That’s where you feel pain everywhere in your body.  The muscles are really aching, and only the most prepared and well organised athlete is going to do well after that.  I’ll go with the pace, but after 30 kilometres, I’ll change to my own pace.  And if you’re ready to follow me, then we can go together.”

Kipchoge may be the greatest of all time who is intent on setting records, but his advice rings true for all of us.  To run a marathon, you must be prepared.  Speak to any experienced marathoner and they will talk to you about the challenge of the final 6 miles.  It is about “your pace”.  Negative splits work for sure, although in my experience, with only the elites going much further than 22 miles in training, the likelihood of speeding up is slim.  When you run 100 plus miles a week and cover the full distance and maybe slightly further on a weekly basis, you may have the conditioning to do it.  For normal people like me, maintaining speed rather than increasing it is much more realistic.  That is why I favour an even pace.

The one method that I have foolishly tried and tested most often is going out fast and trying to hold on.  Regardless of my finish time it has meant slowing down and experiencing some unnecessary pain later in the race. 

Create your own plan.  And stick to it for your best race yet!