- Kevin Bryant
How Much Can You Tolerate?
Welcome to the Elite Sports Medicine and Conditioning blog! Once a month, we’re going to be covering a variety of topics related to sports therapy and rehab featuring posts from each of us. Today we’re going to be discussing an important concept in the development of injuries: load tolerance.
Our bodies and individual structures have a certain capacity for loading, or can only tolerate up to a certain load before they fail and an injury occurs. Quite simply, injury occurs when the loads placed upon our bodies are greater than what they can tolerate. Our capacity is specific to the activities we do and how those activities load specific tissues in our body. To understand this better, let’s go through a few examples.
Picture this: you’re out for a run when you hit a divot in the pathway and you roll your ankle inwards- a classic ankle sprain. When your ankle rolled inwards, the ligaments on the outside of your foot were exposed to a load from your weight landing in that position, and the ligaments were stretched beyond their capacity. This is an example of an acute injury- a one time, traumatic event.
Now let’s say you’re out running, and you’ve been following a running program where your distance increases a little bit every week. Everything is going great, and you feel like you’re getting stronger, so you decide to increase your distance by 500m instead of the prescribed 200m. And then for your next run, you increase again by another 500m, and so on. The next thing you know your achilles tendons are really painful, making it difficult for you to run. You didn’t tear your achilles, but you increased your volume (i.e. load) at a quicker rate than what you were adapting too (i.e. capacity). This is an example of a chronic injury due to training errors.
Here’s another scenario: you need to paint your living room. You want to get both coats done over the weekend, so you put in a long day each day to paint all the walls. As you work, your forearm and elbow start to get more and more sore until you can barely hold the brush without it hurting. The repetitive motions of your wrist over a long period of time has put more load on your forearm muscles and their common tendon than what they can tolerate, and you develop tennis elbow. This is a chronic injury as well from a low load activity but done repetitively over a period of time. This is also an activity you’re not used to to doing, so you don’t have great capacity for this activity to begin with.
These are examples of when the load placed upon our bodies is greater than what we can tolerate. How about this: you’re out running again and each day this week you have been running 5km. But last night you didn’t sleep very well- your child had an upset stomach that you took care of at 3am. You slept in and rushed out of the house without eating breakfast. Plus, it’s been a really stressful week at your office job. You still decide to push through a run despite how tired you are, and after the run your knee is throbbing. Everything is the same in terms of your run- distance, speed, cadence. But your capacity to tolerate this run has gone down today. So much that the load of running is now greater than what you can tolerate.
These are just a few scenarios that highlight the different relationships between how our capacity to tolerate load and the load itself interact every day. Injuries and pain are often a web of factors that culminate to the point of tissue overload, even in acute injuries like the sprained ankle. Our job as therapists is try and help you identify the factors that may have led to your injury, how we can address them, and how we can build your capacity back up.