Why hurt does not always equal harm (persistent pain perspective)

If you have experienced an injury that has turned chronic, then you may well understand that there are adaptations that occur in your body that can leave you feeling ‘not quite like it used to feel’ when you do certain activities. Learning why this occurs is often the first step in managing your persistent pain. We can understand this by exploring the ‘Twin Peaks’ Metaphor described by pain researchers David Butler and Lorimer Mosely in their book Explain Pain (see below). Let’s discuss!


The left side of this diagram shows us that we each have a tissue tolerance line, meaning the limit of how much our body can tolerate before we may start to experience tissue damage. This is based on our fitness level and recent activity exposure, and therefore is unique to us and can change at any given time. Of course, we can exceed this limit if we feel that doing an activity is so highly valued that we are willing to take a risk; we call this a superhuman effort (think of stories where people do incredible things to save the life of another individual, or by deciding to do something that is a major goal for them, like climbing up Mt Everest). Our body is protective by nature and therefore has a warning system to let us know if we are approaching the tissue tolerance line (to avoid harm). This is called our protect by pain line, which naturally sits a little under this tissue tolerance line, you can think of it as a warning ‘if you keep going here, you might cause yourself some harm’. This is all perfectly normal! 


The right side of our diagram shows us what happens after we experience an injury or persistent pain. When we are in pain, we typically reduce our activity levels whether by choice or because of the injury itself, and therefore it makes sense for our tissue tolerance line to also reduce (because our fitness level has somewhat reduced). Our body is such an intelligent system that it adapts to the pain or injury by trying to prevent it from happening again in the future, and it does this by providing a bigger buffer between our protect by pain and tissue tolerance line. In other words, the alarm system will be set off earlier or more easily than it previously did. This is a perfectly normal phenomenon and this buffer is constantly changing depending on many factors. This explains why doing an activity that you may have previously done without pain can result in pain, and why we can experience pain despite being far away from the actual tissue tolerance point. 


The good news is that with the correct dosages of exercise therapy we can begin to increase our fitness (tissue tolerance line) and reduce the buffer by increasing our protect by pain line. We do this by working with the overactive ‘alarm system’ and teaching our body that the movement/activity is safe and will not cause harm. This requires a balanced approach, because if we try to ignore the alarm system or throw ourselves into an elaborate activity beyond our tissue tolerance, we only make the alarm system more reactive and the buffer gets bigger. On the other hand, if we try and avoid activities/movements that are above our protect by pain line, we see continual deconditioning and the alarm system continues to get more reactive. This is where the assistance of a health professional such as an Accredited Exercise Physiologist who is experienced with persistent pain can help you to find and progress your ‘sweet spot’ with exercise over time. 


If you would like to know more about how to manage your persistent pain and get back to your previous activity levels, I’d love to have a chat. 


Tamika Hassum 

Accredited Exercise Physiologist 

True North Wellness 


If you’d like to read more about the Twin Peaks model, check out ‘Explain Pain’ by David Bulter and Lorimer Mosely, or Bodily Relearning by Benjamin S. Boyd.