The purpose of this blog post is to dive into a proposed framework on how running injuries occur. Disclaimer: this is a large topic and you could make entire lectures based off of this, but I want to highlight one infographic that I am partial to.

Before we talk about the infographic, let’s briefly talk about the normality of running injuries.

A study from the International Journal of Sports Physical Therapy in 2016 looked at prevalence of musculoskeletal pain in elite runners. They found that “the prevalence of any running-related musculoskeletal pain in elite distance runners was 75%”.

75% is pretty high, and not to mention these athletes have experience and a wealth of resources to help them recover, train properly, and eat healthy. Now, this is in NO WAY meant to fear-monger, or make people think that running is bad for you. The health benefits of running greatly outweigh the negatives. This article merely illustrates that dealing with musculoskeletal pain is a normal part of being a runner. In other words, you are not alone in your injury, which is comforting, right?

Let’s take a look at the infographic below to explain how someone might get a running injury. You will see there are two lines, a blue line representing load capacity, and a purple line representing a load. There are numerous factors that go into each of these and you can see those illustrated in several boxes. Take a moment to read through them. The point at which an overuse injury occurs is when the load exceeds the load capacity (purple line goes above the blue line).

Pretty simple, right? Not really, again there are so many factors that goes into load capacity and load.

I want to draw your attention to the lower left where it says “previous activity” and “part shown above”. You will see that “rest” takes our blue line or load capacity back up or farther away from the cumulative load line, or purple line, and that “run” brings the lines closer together. Keep scanning right and you’ll see that the timing between rest and running finally cause the lines to intersect (again there are all those other factors in the boxes at play here, not just rest and run). This is what you are seeing in the main picture of the infographic. When the load exceeds the load capacity in tissue that tissue can become compromised. Wait a second though, don’t we have to run and put miles in to get better at running? Of course, but it really matters how we go about that process. In other words the goal is to maintain a delicate balance of putting load on your body so that you get more fit, but also keeping your load capacity high so you avoid injury. Also you have to think of this in terms of day to day loads as well as long term training cycle loads.

So what do we do? This brings us to our next infographic from Jason Fitzgerald. I appreciate him letting me use his graphic. Please check out his website strengthrunning.com. This infographic outlines great practical tips to manage your load capacity and cumulative load (purple and blue lines). Jason breaks it down in to “How to Limit Repetition” (cumulative load) and “Better Withstand Repetition” (load capacity)

Hopefully this has been a helpful read and given you new insights on running injuries and how to understand the factors that go into load capacity and load tolerance.

Feel free to reach out with any training or rehab questions,

-Steve White

References:

A framework for the etiology of running-related injuries. Scand J Med Sci Sports. 2017 Nov;27(11):1170-1180. doi: 10.1111/sms.12883. Epub 2017 Apr 20.
Prevalence of musculoskeletal pain in marathon runners who compete at the elite level. International Journal of Sports Physical Therapy. 2016 Feb; 11(1)126

Unpacking Running Injuries