How far should your longest marathon training run be?

In this guide to pre-race training, we offer marathon tips on how far you should run in the quest to be race-ready for the full 26.2 miles.

You’ll be aware of the importance of the ‘long run’ - but what is it, and how long should it be?

Long run training

Anyone preparing to take on a marathon is only too familiar with the long run, which is understood as a high-mileage workout each week. These runs gradually take on more miles as runners acquire more experience in training, and become more familiar with their bodies, minds and endurance limits.

Long runs gradually accumulate more mileage as race day nears, but we’d typically advise not to replicate a full marathon in training, to minimise risk of exhaustion.

How far should your longest run be?

Marathon novices and old hands alike can never be entirely sure what the ideal long run should be.

There is no one-size-fits-all answer, and everyone’s individual running capacity is unique. What running specialists (like us!) do agree on though is that your longest run should be many miles and minutes shorter than on the race day itself.

Marathon running is a cumulative process based on all your training, not just a single long run, and sensible runners will pace smartly and fuel appropriately. While long runs are important, with some athletes keen to go even further, they are only one aspect of a vigorous training regime. And when you do attempt one, you should not overexert yourself, so as to avoid fatigue and retain freshness.

Focus on time over distance

Runners who are able to complete a few runs that last two to three hours are well-placed to compete on race day. With the correct marathon training plan, your mileage will inevitably rise.

Intelligent training will focus on improving times rather than distances. The emphasis should be on building maximum fitness, which is why it is better to do two or three long runs that last no more than three hours, while swerving excessive mileage.

The error some runners make is in thinking that their body won’t be ready if they haven’t completed over 20 miles, and that they will logically struggle on the final six to seven. But that’s not how it works. With the correct training, pacing, fuelling and rest, you will be in optimal shape to last the course.

How quickly should a long run be completed?

Runners need to also factor speed into their marathon training plan. The pace at which you attempt your long run will ultimately depend on your individual ability and race day ambitions.

Faster runners going for three hours or less should strive for a pace that is up to a minute slower than their target pace on marathon day. Increased speeds mean a higher intensity workout. By reducing the pace of your long runs, you will be more likely to feel energised and remain injury-free in the run up to race day.

Runners aiming for four-to-five-hour times will be more likely to hit their race pace in their longest training session. By placing less load on the body, and at a slower pace, you are better able to recover in time for the next event.

Working out your marathon pace

There are two ways of predicting how fast you can run 26.2 miles. You could either take your 10K finishing time, multiply by five and subtract 10 minutes, or double your half marathon time and add an extra 15 minutes for a rough finish time.

It should be stressed though that these are only approximate estimates, and shouldn’t be treated as gospel. Some athletes lend themselves better to longer distances, while others are more suited to shorter runs.

Extraordinary external factors such as crowding, distraction or the weather may also have an impact. It is worth consulting a pace conversion chart to identify what pace you would need to hit your marathon time goal.

Fuelling a long run

Runners need to be fuelled according to a strategy developed in training. It is a vital part of any marathon running schedule.

Energy gels are recommended as a popular and effective means of accessing carbohydrates while running. By taking one or two over the course of every 60 minutes, it will really enhance race readiness.

Alternatives include sports drinks, bananas, energy chews or Jelly Babies. Each should be tested for efficacy during training runs to ensure the body is comfortable with their absorption.

No matter where you’re based, contact us at Maximum Mileage Coaching today to find out more about preparing for long runs, and how to integrate them as part of your marathon training schedule.