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How is my long run distance calculated in my marathon plan?
How is my long run distance calculated in my marathon plan?
Steph avatar
Written by Steph
Updated over a week ago

Are you training for a marathon and wondering why you don't see a marathon in your training plan? We explain why in the below article but read on to find out how your long run distance in calculated.

Factors to consider when calculating your long run distance

  • Running ability - it takes time to build resilience and endurance so depending on your running experience, we will ensure your longest run won't tip you over the edge. We want to get you to the start line feeling strong, healthy and raring to go!

  • Weekly volume - it is so easy to get focused on the long run but if this is the only training you did all week, you wouldn't be well prepared. We focus on the training week as a whole making sure you get in the right overall mileage and balance of intensity.

  • Length of your plan - how long you are training for an event will effect how far you can go. If you have a longer plan (>14 weeks) then this gives us more time to build up the long run distance and more opportunities to bank longer runs. If you are tight on time and need to follow a shorter duration plan (<13 weeks) then you will see fewer long runs to ensure you get to the start line injury free.

  • Long run duration week on week - as you move through your training plan then your long run will increase week on week with a deload week every 4-5 weeks. To achieve the goal of consistency, your long run will increase by 10-15% each week. This to ensure your body can adapt and recover from the distance. If we increase this too much, then the risk of injury increases significantly.

Optimal Long Run Distance

The optimal long run distance in a marathon plan is 32k (~20miles) on at least one occasion, but for optimal performance we would aim for two runs at this distance. 20 miles (on top the miles you have run throughout the week) is long enough to build your endurance to run the full 26.2. In training this will usually take longer than it will on race day so the overall time on feet will be closer to what you expect to run on marathon day. If this is your debut marathon or you've had a few years off inbetween then this is perfect for you. Those who are more experienced will run longer than 20 miles on one (max two) occasions, but this is because they have been through more than one marathon training block. In some cases, it takes years to be able to tolerate this load. The key is to be able to recover from your long run so it doesn't impact your training the following week. The longer your long run, the greater the injury risk and the harder it is to recover so our advice is to stick with that is best for your ability and lifestyle, and don't up the mileage out of fear. We are confident your Runna plan will get you to the start line feeling raring to go!

Avoiding the Bonk

There is often fear around the last 10k (~6miles) of the marathon. You might have heard horror stories from friends, family or club mates about feeling depleted and hitting the wall. This does happen but majority of the time is due to inadequate fuelling or hydration rather than how far your long run was in training (providing you hit the 32k marker). So this is a reminder to you to practice your fuelling in training so come race day you are prepared, you know what your stomach can handle and you feel confident that you'll have enough energy to soar to the end!


1. It is ok for a to add a second 32km long run if they have only been prescribed one?

Your Runna plan is carefully tailored to your ability, running experience and time to train so we recommend sticking to the prescribed sessions.

2. Is it okay if a User wants to push themselves from 32km a little further to feel more prepared psychologically?

We do not recommend you do this. Your Runna plan has been designed around your ability, number of runs per week and length of your training plan. If you push it too far one a single run then the risk of injury increases.

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