Why do I keep getting injured?!
What’s taking so long for my injury to heal?!
Why am I not getting stronger?!
Have you ever asked yourself any of these questions or have been frustrated with your slow or inadequate recovery following an injury? Well hopefully I can help shed some light onto why you sustained the injury in the first place, why it keeps happening, and/or why you are lacking progress.
I would like to introduce a concept called the Envelope of Function. In simple terms, it encompasses the upper and lower thresholds of load that a specific muscle tissue or body structure can tolerate.
Lets refer to the chart above and break down what each zone means:
Zone of Subphysiological Underload
Here exist the activities that do not stimulate our bodies to make any kind of physical adaptations, such as bed rest or post surgical immobility.
Zone of Homeostasis
This is the zone where we typically live day to day or train to maintain physical health. This can include walking up/down stairs, grocery shopping, doing yard work, running 1 mile, rowing for 30 min, or squatting 200 lbs. In this zone, we can perform all of these activities with no aches, pains, or discomfort.
Zone of Supraphysiological Overload
This is where the bread and butter of training and injury rehabilitation occurs! In this zone, we are providing enough stimulation, load, and discomfort to go just above the Zone of Homeostasis to trigger physiological adaptations, however, being careful not to exceed into the Zone of Structural Failure where injury occurs.
Zone of Structural Failure
Here we have tissue or structural overload leading to failure and injury! For example, lets imagine that you typically run 1 mile with no problem. Now you want to increase your running distance tolerance, so on the next run, instead of increasing your distance to 1.5 miles, you push it to 3 miles and have unfortunately exceeded your tissue load tolerance and entered into the zone of structural failure where you have sustained the injury.
Before we return to the 3 questions posed in the beginning, I want to mention that the the upper limit of the Zone of Homeostasis is dynamic! It can be lower based on injury or surgery, and multiple factors such as nutrition, sleep, and recovery from previous exercise sessions that could affect your current load tolerance. But, it can also be higher with appropriate dosage of training, allowing you to tolerate higher loads with minimal discomfort and injury risk.
So now we can relate the concept of the Envelope of Function to Physical Therapy and the 3 questions from the beginning:
Why do I keep getting injured?!
Your training/activity load and/or frequency is set too high for your current physiological capabilities and you keep entering into the zone of Structural Failure. This is often seen when an injury is under-rehabbed and the person returns to their previous level of activity too soon resulting in constant re-injury!
What’s taking so long for my injury to heal?!
You are likely under-dosing the rehab stimulus and operating close to the lower end of the Zone of Homeostasis and maybe even in the Zone of Subphysiological Underload. Injured tissue needs a certain amount of stress to help it repair and rebuild stronger to raise that Envelope of Function!
Why am I not getting stronger?!
Again, this is likely due to under-dosing your strength program, either not enough load or not enough frequency, or a combo of both! You’re likely staying in that Zone of Homeostasis and getting just to the upper limits but not breaking into that Zone of Supraphysiological Overload where all of the good stuff happens.
With a comprehensive evaluation at STAT, a Doctor of Physical Therapy applies these principles to help uncover the root cause of your issue, intervene to stop the injury cycle, load with the proper dose of exercise prescription, and build robust and resilient tissues to prevent future injuries!
