Demystify Running Injuries

A majority of runners have experienced that horrible feeling. A pain, a tweak, a soreness, suddenly appears and with it, all the worries about how long this will last and how it will upend training. It may happen during a training run or an important build-up during a training cycle. No matter when or how it happens, it always seems to pop up out of nowhere. 

While it seems like running injuries magically appear without a trace, if we delve into the details of a runner’s lifestyle and training, there is often a reason for the injury to occur. Running injuries usually occur with a similar pattern of events and thanks to an article by Bertelsen et al. in 2017, we have a framework to understand how running injuries develop, no matter if it is a tendinopathy, a complex bone stress injury, or other injury.

To understand running injuries, we must first understand two important concepts; load and capacity. Load can be thought of as EXTERNAL. Essentially, load is the magnitude of strain placed on our body. For example, lifting a 200-pound weight is much more “load” on our body than lifting a 20-pound weight. And running 20 miles is much more “load” on our body than running 2 miles.

Capacity can be thought of as INTERNAL as the amount of strain our body and tissues can tolerate. If the most we have lifted before is 50 pounds, our body likely does not have the “capacity” or ability to lift 200 pounds, but we can likely tolerate 20 pounds. Similarly, if the most we have run is 5 miles, our body and tissues would likely not have the “capacity” for a 20-mile run.

Many factors affect both load and capacity. Load can easily be affected by weight, the type of shoes we wear, running surface, our running mechanics, run distance, run intensity, and much more. In addition, capacity can be affected by our training load, past workouts, sleep, nutrition, recovery, and others.

The interaction between capacity and load essentially determines our risk for running injuries.

If we look at the first graph, it tracks an individual’s capacity as they go through a training cycle. You will notice increases and decreases in capacity simply because capacity constantly fluxes every day and every week of training. Capacity decreases during individual workouts because our muscles and bodies fatigue. But, if we structure workouts appropriately, our body structures will grow stronger, thus capacity will increase over time. 

Then if we impose load on the graph, you can see they have an inverse or opposite relationship. As load increases, our capacity decreases because of fatigue. Oppositely, if we decrease load and give our body a chance to recover, capacity increases. In a healthy relationship between load and capacity, when load stays in the green area under capacity, then our load is well within our capacity, or limits. As a result, our bodies and structures can tolerate the load, so this reduces the risk of injury. 

Alternatively, let’s look at an unhealthy relationship between capacity and load. Once again, we can see that capacity and load are opposite of each other. However, towards the end, we do not give our body a chance to recover and load continues to increase while capacity decreases. As a result, load goes above and beyond the green area and exceeds our tissue’s capacity. As a result, this places our body at an increased risk for injury. 

It is important to understand that an injury will not immediately happen as soon as load exceeds tissue capacity. However, if we make this a constant habit and do not correct and adjust, there is a much greater chance for injury to happen.

Everything in our training relates to tissue capacity and load. It should always be the goal to keep a healthy balance between the two. Healthy training will also gradually increase capacity because then we can tolerate greater load and increase our gains from training. 

Ultimately, this balance can be a bit tricky to understand day in and day out. So make sure you chat with a physical therapist or coach to better understand the relationship. If questions remain, schedule a free 15-minute Discovery Call with Matt from BioEndurance to help bridge the gap, answer questions, and keep you training!

References:

Bertelsen MLH, Hulme A, Petersen J, Brund JK, Sørensen H, Finch CF, et al. A framework for the etiology of running-related injuries. Scandinavian Journal of Medicine & Science in Sports. 2017; 27(11): 1170-1180. https://doi.org/10.1111/sms.12883