Warning: This is a slightly longer read than usual but it sets the foundation of future blogs.
The concept of Load vs Capacity relates to all types of aches, pains, and injuries. In this post, we’re going to talk about it in the context of the majority of back pain cases. While this isn’t always the full picture, it tends to explain most of it.
When the load placed on the back exceeds it’s capacity, the nervous system gets concerned and protective. We’ll talk more about pain in future posts, but for now, understand that back pain means that your back isn’t happy for some reason (no kidding, right?).
While this might sound obvious, it’s actually the key to understanding how you came to have back pain, and how you can get pain-free.
To gather the full picture, we first look at these individually, then put them back together.
For the purpose of this explanation, we define load as: what we are asking the back to do for a given period of time. This includes repetitive tasks, doing things which require strength as well as doing things in sustained and/or awkward positions.
The simplest question you can ask yourself is: “What have I been doing that gets my back to work more than usual?”
Things that modify the amount of load your back experiences are usually activity related. A frequent cause is an increase in work that it was not prepared for. A great example is moving bags of concrete on the weekend.
To be fair, sometimes it’s not quite so simple. When back pain has been going on for quite some time, the overload can be more subtle. A classic example of this is having to lift things at work (boxes, children, etc) but your body was not ready for some unknown reason and it is having trouble adapting.
These are the load related things we want to know about in the clinic:
There are a lot of things that we don’t realise affect our capacity. This is important because when our capacity is reduced, we cannot tolerate as much load. This is a major reason why two people can be doing the same job and one person gets back pain while the other doesn’t.
Here’s a short list things that modify capacity and why they matter.
Sleep: When we get less sleep, our body has less capacity as it’s regenerative and healing time is decreased.
General stress: The associated increase in stress hormones when we’re stressed also reduces our capacity. This often affects our sleep too. Just as when you’re stressed it’s harder to deal with life’s problems, when you’re stressed your back finds it more difficult to meet its demands.
Recent major stressors: This is more important than you’d think. There are 2 key reasons, each of which warrants their own blog post. In short, when we experience high levels of stress, we enter into fight or flight mode. This leads to us finding it more difficult to get back into the “rest and digest” mode that helps us to sleep, heal, and recover. The other thing it does is encourages us to breath through the upper chest rather than using our diaphragm. This can severely impact the mobility of the rib cage, leaving the rest of the back to take over the work.
Training/Fitness: As in the case of the weekend warrior, if you’re body has not adapted to moving bags of concrete then it has to work much harder. This is often what we think of as affecting the back’s capacity to do something. While you might be generally fit and strong, there is such a thing as “task specific fitness”.
Age: As we age, our ability to bounce back and recover starts to slow down. On top of this, after roughly the age of 30, we start to lose bone mineral density and muscle mass. It’s quite easy for those of us getting older to go out all guns blazing like we used to when we were younger.
Injury history: Previous injuries can result in the back taking over more than its fair share of work. More on that in a future post but a quick example is a sprained ankle. Say you sprain your left ankle. Despite it feeling better, your body got used to trying to take the weight off it and transfer weight over to your right side. To do this, it usually uses the muscles on the side of the back. Got one sided back pain? Maybe this is you.
While it’s not simply a case of load exceeding your capacity and BAM! back pain, the majority of the time, it’s tells the story of how you got here in the first place.
Now that we know how we got here, we know where to focus our attention in order to get you back pain-free (yep, another back pun).
Here’s a quick and easy exercise you can do at home. I call it Back Tracking, as in working backwards. Go get pen and piece of paper.
Go on, I’ll wait.
…..
…..
Now we’re going to create two columns. One with the heading Load, and one with the heading Capacity (you can probably see where we’re going with this).
List all the things you can think of that fall under each heading using the examples above to guide you. This (should) now be a complete list of all the things that contribute to how much work your back is doing and how well it can tolerate it. From here, you have three choices.
1. Do nothing with this and hope things will feel better.
2. Bring this in to the clinic and we can go through and make a plan for you to get pain free using our session time which would normally be spent doing this activity.
3. Note the most impactful items on this list and work on changing them which will get you going in the right direction. You may just find the answers on how to do this in future blog posts 😉
While it might look simple in this blog post, there’s an art to understanding all the pieces of the load vs capacity puzzle. That’s where an in-person physiotherapy assessment comes in. Book online now to get the pieces of your puzzle and remove the mystery from your back pain.
