How to Pace an Ultra


This has to be the most common question I am ever asked as a coach. Bottom line, getting the pace right, particularly in the first few hours of a race, will have a massive impact on the outcome of your race. Start by going too fast and any time you made up in the first half of a race, and not to mention potentially a lot more, will be lost in the second half. In fact, very few races are lost due to going too slow at the start.


Photo: Claus Rolff

The effect of running too fast in the beginning

Running too fast has a number of major negative effects on the body. Not only does it burn more calories but burns more calories from carbohydrates instead of fats, and as such does more damage to your leg muscles. Burning more calories from carbohydrates means you have to replace more calories, which will inevitably increase your chances of suffering gastric problems, a major reason for DNFs in ultras. Doing more damage to your leg muscles in the early stages is not something you can recover from during a race; once the damage is done it’s done, and you’ll have to deal with the consequences later on.


How slow should you go at the start?

In a race where the terrain varies so much, how can you set a target for your running pace? In a marathon the goal is to try to run the second half as close to the speed of the first half as possible. In most hilly ultras 100% of the field will run the second half of the race slower than the first, and usually by a significant amount. But those who can slow down the least will usually be at the front of the field.


The danger of having fresh, tapered legs is that your long run training pace now feels very easy and the temptation to run faster is extremely high. However, in shorter races your race pace is faster than your training pace, but during ultras the race pace is often slower than your training pace. So if you start the race at your training pace, it is often not sustainable and will usually result in quads that have had enough well before the end of the race.


My advice is to ignore your watch completely and not worry about measures of speed or heart rate. Make sure the first hour feels more manageable than your normal easy run. The longer the race the slower the race pace will be relative to your training pace. Focus on your breathing and perceived effort, making sure that the undertaking feels easier than your long training runs. Don’t worry about losing time in the first few hours, your patience will reward you with legs that can still run in later stages of the race.


Taking it easy at the start of the race requires discipline, patience, and the ability to put aside your ego. The start of an ultra is not the time to let your competitive nature show itself.


In some races there is a mad sprint to get to a climb or single track before the masses to avoid getting stuck in a big line. You need to ask yourself how much time you will actually lose getting stuck in a queue of people versus losing time later in the race due to your legs being exhausted and preventing you from finishing. For most people the damage done running too hard at the start will far exceed any time lost waiting in a queue.


Running versus walking uphill

When to walk and when to run is another difficult decision. Running up hills early in the race can burn up a lot of calories that you may struggle to replace later on. Once again the key is to focus on intensity. As soon as you feel the intensity rise, slow down the pace, and if that means that for some time you have to walk, then so be it.


How fast should I run down hill?

Whilst running down hill requires less aerobic energy, it places much more pressure on your quads. Run down hill too fast and you’ll overload your quads, making running later in the race far more difficult. For this reason, when running down hill you can’t ultimately rely on intensity to be the measure determining your pace. You will need to think about the load on your quads, making sure it doesn’t significantly surpass what you’d experience running on flat terrain. Focusing on minimising the load by running with smaller, faster strides and light landings to reduce the strain on your leg muscles will help you avoid incurring any undesirable damage.


The one golden rule to remember when working out the pace at which to run an ultra is: if you think you are going too fast, you are, and if you think you are going too slow, you aren’t.


Article by Andy DuBois published in Asia Trail in November 2014.


Andy is an award-winning personal trainer and elite endurance athlete specializing in ultra running. You can find more useful info on his ultra running coach website (www.


  1. Kitty says

    This article is wonderful. I am late to read it. I took part Ina trail race 2 weeks ago. The route started downhill first, then flat road, followed by up and downhill and finally climbed up a lot. I was too fast in the beginning thinking the downslope was easy to go. I did not notice my quads was hurt already until I reached the up and down part. I slowed down and lost time, much more than I expected.

    Don’t be tricked by the “downhill”!

  2. Guillermo says

    Indeed a very wise article to let your body compete in a more natural way. May I add that another benefit of slowing down the pace is giving extra time to your nutrition to really get in the body. I have experienced that hard to find pace where despite the many hours on the trail the energy levels remain high.

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