Biomechanics is the study of the structure, movement and function of living organisms. In physio and orthopaedics, we often see people with movement-related pain. This could be due to muscle weakness or people lifting things in the gym that are too heavy to perform correctly. Not every condition has to be related to structural damage such as a broken bone or a torn ligament. Therefore the first difference we need to look at is whether the altered movement is structural or mechanical. Structural means things like arthritis of a torn meniscus. Mechanical means things like muscle weakness or reduced mobility in a joint. We see different biomechanical presentations through different age ranges e.g. children with knee pain secondary to their hip structure vs the older adults with knee structural changes due to osteoarthritis causing differing biomechanics at the hip. These differ from the mechanical presentation we see e.g. weak gluteal muscles causing the hip ‘drop down’ when walking, leading to lateral hip pain. A great example of biomechanical pain is the knee, hip or lower back pain after a sprained ankle. In the first few days of severe, we limp causing changes to our normal gait patterns causing increased load to other structures

As with most areas of the body, physiotherapists almost always look at other joints and like to assess things from a more functional perspective. This is particularly relevant when we assess the lower limb. Simply looking at how much the knee bends or your hip extends may not be particularly useful. If you come to physio with knee or hip pain, most of the time, the physio will review your walking, squats, lunging and other tasks to see how things move functionally. And that assessment starts straight away in the waiting room. We'll be watching the way you get up from your chair, pick up your bag and walk into the clinic room. We will be comparing left with right, looking at ‘normal’ movement patterns and normal joint ranges. Now I'm not saying that an assessment specifically looking at the knee is worthless. Quite the opposite actually, particularly when it comes to ligament injuries and laxity at the knee. However, only a small percentage of our patient group come in with ligament rupture that requires surgical intervention.

Note, I say normal in quotation marks. This is because it's hard to define what normal movements are. With almost every patient, I'm sure we could find an altered movement or asymmetry in the bodies natural resting position. This, therefore, is not saying that every impaired or altered movement is abnormal. No one is perfect. We all move differently. Just because we notice the left shoulder moves differently to the right, doesn't mean that's the issue and that's what's causing your pain. However, what I will say is that if you are in with a physio, it's not for no reason therefore sometimes these altered movement patterns may be the issues. 'Flat feet' is probably a good example of this. Many people are 'flat footed' therefore we can describe this as a normal variant. If I see a 50-year-old with a new onset of knee pain and I see flat feet, I'm not putting all my eggs in one basket and blaming that. After all, they've probably had around 49 years of walking with no issues, so why are those feet an issue now. However, if I see a 35-year-old, with knee pain, and flat feet and they've recently started a half marathon training programme, then maybe this is something we need to look at. Along with probably overtraining, a footwear review and a lack of strengthening included in their programme.