Sydney Running Coach Guide: Why Running In The Grey Zone May Not Be The Best Way To Train

With the City2Surf just behind us and the Sydney Marathon here in a few weeks, there are a lot of runners out there training. And for many, finding the right balance between harder training sessions to maximise their improvement, and easier sessions to allow enough recovery, is a constant battle. “Grey Zone Running” is a type of session used successfully by some athletes in their program, but could it be right for you? In this post we give you tips from Sydney running coach Ben Liddy, and review the pros and cons of running in the grey zone to help you decide if you should include it in your training program.

What Is grey Zone Running?

Grey zone running is traditionally thought of as running that is done on a runner’s designated “easy” day. It means running at a pace that is too fast to allow for proper recovery, but not fast enough to provide any real meaningful training stimulus. “Easy Running” days are typically thought of as days where a runner would run up to a limit of 70% of their maximum heart rate, with a large majority of the run falling below that. Typically “Grey Zone” running would be described as runs that fall between 70-80% of the runner’s maximum heart rate.

Faster running requires more force production so there is no doubt that running at a higher percentage of your maximum heart rate causes an increased stress on your body than running at a lower percentage. Will this increased stress cause an athlete to get injured running at a higher percentage of heart rate maximum? There is no simple answer to this question because there are so many variables involved, but it makes sense that a runner’s risk of injury increases with trying to run faster on their easier days.

What Are The Benefits and Risks Of Grey Zone Running?

There is no doubt that you still get benefit from running in the grey zone. Training benefits don’t just stop because you did that designated recovery run a little harder than normal. But what it means is that now your recovery requirements are greater. Instead of doing a single harder session followed by

a recovery run, you now have a harder session followed by a moderate day. If the next day planned is another harder session we now start to have an issue. Your body can only respond to so many stimuli before increasing levels of fatigue occur, or your body begins to break down and injury occurs.

How Does Grey Zone Running Affect The Rest Of Your Running Training?

You may be able to get away with grey zone running and continue to stay healthy and improve if your designated harder days aren’t too hard. Some athletes prefer not to push themselves too hard during the more intense sessions, because for them this is where injury risk occurs. They prefer to finish feeling like they had a fair bit in reserve, and be able to recover quickly for the next day. In this case the muscle breakdown from the session may be a lot less and they can feel comfortable the next day pushing their runs a bit, allowing them to include grey zone sessions in their program.

Alternatively, athletes who have trained very hard the day before carry residual fatigue into the recovery days. This means that they need to run very slow and with lower heart rates, as their bodies are not ready to push again. For this type of athlete, grey zone running the day after their harder sessions is likely to significantly increase their injury risk.

Is A Polarised Approach To Running Training Better?

Most studies on distance running suggest that training with a more polarised approach, where hard days are hard and easy days are easy, typically produce the best long-term results. There have been very successful athletes who have achieved great results running in the grey zone on their recovery days, so it can be done, but for me the risk of injury is too high.

Many of the benefits achieved in grey zone running are achieved at lower heart rate percentages, so it makes sense to minimise the risk of injury and ensure the recovery days truly are recovery days. It allows for better recovery before the next harder session, and these harder sessions are where the meaningful training adaptations occur.

Questions & Answers

Frequently Asked Questions

1. What is the grey zone in running training?

The grey zone in running training refers to running at an intensity that’s too fast for recovery but not fast enough for significant performance gains, typically at 70-80% of maximum heart rate.

2. How can I avoid grey zone running?

To avoid grey zone running, monitor your heart rate during easy runs. Keep your heart rate below 70% of your maximum, with the majority of your run being well below this.

3. What are the risks of grey zone running?

Grey zone running increases the risk of overtraining, fatigue, and injury due to insufficient recovery between hard training sessions.

4. How does a running coach help in marathon training?

A running coach can design a tailored training plan, helping you avoid common pitfalls like grey zone running. They can structure your training sessions across the week to balance the training stimulus from harder sessions, with the recovery needed during easy runs. This helps you get the maximum gains in your running performance while helping to minimise your risk of injury.

5. Can grey zone running ever be beneficial?

While grey zone running can offer some training benefits, these benefits can typically be achieved with lower-intensity runs that also provide better recovery. However, some athletes who prefer not to train too hard in their “harder” sessions can safely include, and benefit from, grey zone running sessions in their program.

6. Why is recovery important in marathon training?

Recovery allows your body to repair and adapt after hard sessions, reducing the risk of injury and improving overall performance during your marathon training. It helps to maximise your performance gains by allowing you to work harder in your “hard” sessions, while minimising your risk of picking up an injury due to over-training and fatigue.