A solid marathon finish will be determined by undertaking correct, consistent and specific training, aided by adequate running experience, patience and above all sensible pacing. But if you are running your first marathon, or are coming back to the distance then how do you know what pace to hold?
Let’s look at a couple of strategies that you’d do well to avoid. The first thing NOT to do is to pick a time you ran a marathon in the past; too often you’ll see an athlete say “well I ran 3:25 in 2016 so I want to run that time – or more likely I want to beat that time - and will hold 7:50 per mile (4:52 per km). You need to plan your race based on your current ability, you can adjust this ability as your training progresses and you obtain times from build-up races and/or you feel that your pace versus effort is edging forward. The second strategy to avoid is to pick a “sexy number”; we are naturally drawn to even numbers, the four minute mile, the 10 second 100m so it’s unsurprising in the marathon world that we want to run sub 4:00, sub 3:30, sub 3:00 etc. These are actually just random numbers despite them seeming neat to our mildly OCD brains. A 3:34 marathon given our training, the terrain, the weather might actually be a better result than a 3:29 – it’s just we tend not think that way.
Having looked at what not to do, what is it we actually can do. There are a number of online predictors available, from the likes of Runners World, Running Times, Daniel’s Running Formula and Marathon Guide, and these are a good starting point. Using finish times from shorter races these calculate a predicted marathon finish time. The formulas behind these calculators are similar but not exactly the same so different calculators may give you slightly different finish times but typically they fall around 5 minutes of each other. The caveat I would add is that this is your predicted marathon finish time IF you do the marathon training. So online predictors are a good place to start.
One predictor I have always used and found to be both accurate and useful, as you can do the maths in your head, is from the late great Frank Horwill who stated that if you take you 10km time, multiply it by 5 and then subtract 10 minutes you will get your predicted marathon time. So, a 40 min 10km runner would take 40 multiply by 5 = 200 subtract 10 = 190 so their predicted time would be 190 minutes or 3hrs 10 minutes.
I often talk about Process rather than Outcome and of course selecting or predicting a finish time is outcome focussed. A more Process orientated approach is to look at what pace you can hold. A way I like to estimate this is to do a longer “kick down” run. Let’s take our prospective 3:25 marathon runner; towards the end of their training block I would have them run 15 miles, the first twelve holding 7:50 per mile then kick down on the last three so they might run mile 13 at 7:47, mile 14 at 7:45 and mile 15 at 7:42 for example. This is a good indicator that holding 7:50 for 26 miles is a strong possibility.
Clearly this subject is not an exact science and the best predictor of what time you can run in a marathon, is to run a marathon. There are many other facets that can come into play; your gender; are these predictors equal across genders? Your age, your athletic age and your running and marathon specific experience. Your previous and recent training. Have you any chronic or recent injuries? Your propensity to longer or shorter events, your ability to burn fat as a fuel, the race day weather and of course the marathon route and terrain to mention a few. However, hopefully you are now better armed to more sensibly judge your potential marathon finish time.
Keep smiling.