How do I know if I am running too fast/slow for my event and why do we run slow? 

TRM Edition 48 Cover

This article first appeared in TrailRun Magazine Edition 48

Understanding Optimal Pace: Why Slower Running Enhances Performance

As a running coach, I'm fortunate enough to speak to people about trail running on a regular basis. One of the most common questions I am asked is “How can I run faster?”  After reviewing training logs and data, the most surprising answer to many is, telling people to slow down. Whilst this sounds counterintuitive, let's dig into the reasons for running slow, the why, the what and as important for you, how slow, should your slow and easy runs be? 

Why do we run slow to speed up? 

Running easy allows us to build up our endurance, through being able to add more distance and volume throughout the training week.  Very simply, we can run a lot more when running easy and gain all the same benefits, without the added stress or risk of injury of more intense sessions. 

Not just taking my word for it, let’s dig into what the science says about performance and running slow.  There have been several studies that have concluded that both the volume of running and the intensity (speed/pace) at which we run lead to performance improvements.  A recent study in 2020, using a real-world big data set, concluded that: 

Our findings can be interpreted as faster runners train typically at lower relative intensities which is consistent with high-intensity performance improvement due to low-intensity training.” 

Very simply, the study found that faster runners spend most of their time training at an easy and relatively slow pace.  The keywords are relative intensities.  Your easy pace may be a fast effort for someone else and too slow for another runner.  Your easy pace is specific to you and don’t chase those PBs every run. 

What is it about the easy run that improves your running performance? 

Easy runs create several adaptations in the body, that lead to improved performance or running economy.  Mitochondrial biogenesis and capillary density are a couple of the key ones, meaning we can run our favourite trails faster with less effort overall. 

Mitochondria biogenesis.  Mitochondria are found in the cells of our muscles and are the powerhouse in the production of energy during exercise.  Mitochondria convert oxygen and our energy stores (glycogen, proteins, and fats) into usable energy for the muscles allowing them to contract, which in turn is us running.  The more mitochondria we have, very simply we can generate more energy for our muscles to run. 

Increased capillary density.  Capillaries are our smallest blood vessels and deliver oxygen to our muscles.  The larger the number of capillaries around each muscle fibre, the faster you can deliver oxygen and fuel (all those gels) to the muscle and take waste products away, again leading to that quicker pace, whilst feeling easier. 

Additionally, we become better fat-adapted, in that we use a higher percentage of fat as a fuel source during these easy runs.  During racing and events, that translates to us relying slightly less on what’s available at the aid stations. 

Knowing the why and what, let's jump into what it means for you and your training for that next big trail race. 

How slow should I be running and how often? 

We know through research that those at the pointy end of any trail race will practice most of their training at a relatively easy pace (remember your easy pace will not be anything near an elite runner’s easy pace), whilst only a small number of us recreational runners practice this. 

There are a few ways to work out your easy pace, some require medical devices, not available to many runners, or using heart rate and power if you have the equipment.  The one method all trail runners can embrace requires no technology at all and that is the rating of perceived exertion or RPE. 

RPE has proven to be highly effective, all you need is a scale of 1-10.  Where 1 is you’re sitting watching a movie, and 10 is that all-out hill sprint.  Another great reason for using RPE is because, during a trail race, everything else is irrelevant, except how you feel at that time, be it running that steep trail to a summit in the blazing sun, or doing a fast descent, it really is about how you feel at that time. 

So where should be aiming for in the RPE scale and how do we know if we are running easy.  We can gauge this through a talk test, anything between 4-6 on the RPE scale can be classed as easy or normal running.  At this pace you should be able to hold a conversation very easily with your training partner, without pausing.  Anything over this and you starting to push it a little too hard. 

How much of your training should be easy?  This depends on your event and distance, for ultra distances you could do nearly all your training easy.  For other events whilst there are numerous approaches to training, you won’t go wrong if at least 70-80% of your time is spent at that easy pace. 

Next time you head out, remember slow and easy wins the day: 

  • A slower pace is a relative to you, don’t compare your pace to others  

  • It can take a little getting used to, persevere and you’ll reap the benefits 

  • Do the talk test, if you can’t hold a comfortable conversation, slow down 

  • Don’t worry about slowing down, you’ll gain those same benefits as running faster 

  • It’s highly unlikely you’ll run too slow

 Ash Daniels is a Level 3- Athletics Australia Performance Development coach at Journey2Ultra coaching, where he specialises in Trail and Ultra running.  He coaches runners of all abilities and distances, believing everyone is a runner, some of us just need a bit more help in getting going.  Ash can be found at