Injuries and injury management all come down to load. The injury process itself is always characterised by too much load. Sometimes this is too much load all at once, for example where an object impacts with a part of your body and causes trauma. However in many instances it is inappropriate load that builds up over time. We may lack recovery time between repeated loading cycles, or the load may be slightly too much for our body to bear. In some cases the load may not be enough and the area becomes unable to withstand “normal” loads, and in some situations there is too much load in one direction and not enough in another direction which creates an imbalance.
Often we are unaware of loading issues until pain rears its ugly head. If you have ever started to experience pain and there doesn’t seem to be an easily identifiable or logical trigger for that pain, it is likely that loading issues have been simmering away in the background and the onset of pain coincides with reaching a threshold where the body can no longer tolerate the stress associated with this load. A classic example of this is where someone experiences severe back spasm and pain while leaning forward to pick something such as a pencil up from the ground. The weight of the pencil is negligible as is the action, however when the area has been constantly under loading stress and has reached its threshold, this simple movement is enough to trigger what appears to be an out of proportion reaction.
The mechanical properties of each of our body tissues is slightly different to support the differences in their role. Bones are designed to tolerate large amounts of compressive loading. Tendons on the other hand are designed to handle what is called tensile loading which is the force that is created when muscles “pull” on the tendons to either stabilise or move a joint. Ligaments are designed to withstand forces in multiple directions to reinforce the stability of the joints.
When an injury changes the integrity of the above tissues, it is important to modify the loads on the tissues to allow for complete recovery. This will be different depending on the tissue injury type. In the early stages of bone injury management, reducing compression loading and restricting movement is important to allow a bone callus to form and start the healing process. This is usually why a cast is placed over the injured area and crutches are used. Most other tissue injuries (such as muscle sprains, tendon strains and ligament injuries) require modified load to heal and can actually become weaker if we completely remove load. Finding the balance here is essential though as too much or inappropriate load will delay and negatively influence recovery, and too little load will weaken the tissue and the surrounding areas.
Different body parts are also have differing loading conditions that are based on their function. For example it is often more challenging to reduce loading on the legs and feet as we use them to walk around and support our bodyweight while standing. This is different to the arms, where it is much easier to try and limit the loads and restrict their use. Postural loading of the back and the neck regions are also more challenging to manage as we load and use these areas any time that we are not lying down. This is also the reason that we can have “bad” days without knowing what caused the increase in pain. Often the accumulated loading on these areas from our normal day to day activities builds up and eventually exceeds the threshold of the tissues which we forget is already reduced through injury.
The thresholds that determine how much load our tissues can tolerate are not just governed by their mechanical properties. These thresholds can be altered by many other factors including nutrition, sleep and stress. Nutrition is what provides our cells with the environment to remain healthy and to recover from damage. Good quality sleep is important to ensure that cell turnover and recovery is supported. High levels of sustained stress can result in low grade inflammation throughout the body which can negatively influence tissue health and will prolong the recovery process.
Monitoring your situation to determine if your loading is appropriate can be done in many different ways. The most obvious way is recording the day to day pain levels and trying to associate this with activities that relate and can load up the injured area. When doing this it is important to understand that the pain may be delayed relative to the loading and isn’t always present or strong at the time of loading. For example with tendon and ligament injuries it is not uncommon for pain to be up to 2 days later.