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Mastering Injury Prevention in Running - The Essentials of a Healthy Running Plan

Learn about two basic principles to reduce injury risk during a running program.
Written by
Christian Peters
Published on
Jan 12, 2024

Exploring the Foundations of a Safe and Effective Running Program

From the 10% Rule to the Acute to Chronic Workload Ratio for Injury Prevention

Injuries are a part of any sport and running is no different. Whether you're an experienced marathon runner or training for your very first 5k you may find yourself nursing an injury at some point in your training cycle. Fields et al discovered that 40-50% of all runners experience an injury at least once per year.1 The goal of this article is to discuss a few strategies to reduce our injury risk by utilizing the 10 percent rule and acute to chronic workload ratio (ACWR).

What is the 10 percent rule?

The 10% rule is like a safety guide for runners. It suggests that you shouldn't increase your running volume by more than 10% each week. This rule helps your body adjust to the stress of running and lowers the chances of overtraining injuries, like stress fractures, tendinopathies, or muscle strains. By following the 10% rule, runners find a good balance between improving their aerobic capacity and not overloading their body.

To break it down, if you're currently running 20 miles in a week, the 10% rule means you shouldn't run more than 2 extra miles in the next week. This allows you to become gradually accustomed to the increased volume that you are placing on your body. Whether you're new to running or you've been doing it for a while, sticking to the 10% rule is a great way to progress your running volume, and ensure your body is able to keep up.

Relying solely on the 10 percent rule for running may present limitations in crafting an effective training plan, though. Runners with different backgrounds may have varying capacities to adapt to increased mileage, and a rigid adherence to the 10 percent rule may lead to either insufficient or excessive training for some. Additionally, the rule primarily focuses on volume without considering the intensity of workouts or the importance of rest and recovery. Ignoring these elements could result in overtraining, fatigue, and a higher risk of injuries, which is why we recommend the utilization of the 10 percent rule when in accordance with the Acute to Chronic Workload Ratio.

What is Acute to Chronic Workload Ratio?

The Acute to Chronic Workload Ratio or "ACWR" is a concept commonly used in the sports training world to monitor training load and assess the risk of injury. The ratio is a retrospective measure as it compares the acute workload (short-term training load) to the chronic workload (long-term training load). The idea is that a sudden change in your effort and training load in the short term, especially when compared to your long term training load, may increase your risk of injury.

For running programs, the acute workload is typically calculated based on the training load over the past week, while the chronic workload is based on the average training load over the past four weeks. The “workload” with running is measured using a rate of perceived exertion scale that ranges from 0-10. The formula used to calculate this data is as follows:

ACWR = RPE average of one week of training) / (RPE average of four weeks of training)

Interpretation of ACWR:2

  • ACWR values below 0.8 are generally considered safe, but the athlete may be leaving improvements on the table.
  • ACWR values between 0.8 and 1.3 is considered to be the ideal range for fitness gains while minimizing injury risk.
  • ACWR values above 1.3 are associated with an increased risk of injury, as they indicate a rapid increase in training load compared to the athlete's usual workload.

Keep in mind that individual athletes may respond differently, and other factors such as fatigue, recovery strategies, and overall health should also be considered when interpreting ACWR values.

Smart Running Plans for Success and Safety

If you are looking for a program that includes these principles, consider starting with our meticulously crafted 5K and 10K training templates, designed to optimize your performance while prioritizing injury prevention and ensuring sustainable progress.

Our programs integrate the proven 10 percent rule, ensuring that your weekly mileage increases gradually, allowing your body to adapt and minimizing the risk of injuries. Additionally, our templates are pre-built with an easy system to determine your Acute to Chronic Workload Ratio. This dynamic combination of the 10 percent rule and ACWR ensures that your training is not only challenging but promotes a healthy balance between intensity and recovery.

Whether you're a novice runner aiming for your first 5k or an experienced marathon runner seeking to improve your personal best, our scientifically informed templates provide a roadmap to success, helping you achieve your running goals while safeguarding your long-term health and training availability. Lace up and experience the joy of running with confidence and longevity!

Here is a screenshot illustrating the second week of our 5k template, displaying the integration of both the 10 percent rule and the Acute to Chronic Workload Ratio.

Explore our range of Running Templates and purchase options by clicking here.


  1. Fields, Karl B.1; Sykes, Jeannie C.2; Walker, Katherine M.3; Jackson, Jonathan C.4. Prevention of Running Injuries. Current Sports Medicine Reports 9(3):p 176-182, May 2010. | DOI: 10.1249/JSR.0b013e3181de7ec5
  2. Maupin D, Schram B, Canetti E, Orr R. The Relationship Between Acute: Chronic Workload Ratios and Injury Risk in Sports: A Systematic Review. Open Access J Sports Med. 2020;11:51-75. Published 2020 Feb 24. doi:10.2147/OAJSM.S231405