Anyone who has followed the evidence in health & fitness over the last 3-5 years has likely seen a rise in the popularity of pain science. The rise in popularity of pain science has also created a decline in the popularity of biomechanics as well as a bit of backlash against the biomechanics industry. While biomechanics aren’t as relevant to pain (particularly chronic pain) as some may think there still are certain situations where biomechanics matter.
Before I get this article rolling there are a couple things I have to mention first
1) I would be remised if I didn’t mention my fellow Canuck Greg Lehman for the great work that he’s done discussing when biomechanics do and don’t matter in pain & injury. Look at his website www.greglehman.ca, his appearances on The Physio Matters Podcast and his presentation from the San Diego Pain Summit.
2) For the sake of keeping this article short and not bogged down in references I don’t have every single article on biomechanics and pain/injury cited in this blog.
With that out of the way here is when biomechanics do and don’t matter…
We know from the scientific literature that certain biomechanical movement variables can be risk factors and/or mechanisms of certain injuries such as
- Loaded spine flexion and disc injury1
- Dynamic knee valgus & ACL tears2, PFPS3, patellar dislocations4 and MCL tears5
- Various FOOSH (fall on outstretched hand) injuries such as scaphoid fractures6 and AC joint separations7
- Ankle inversion & eversion sprains8,9
- Shoulder (and hip) abduction & external rotation and dislocations10,11
- Prolonged postures and musculoskeletal pain12,13
The things you have to keep in mind when looking at biomechanics are ...
1) A lot of biomechanical variables that people cite in their assessments & clinical reasoning models either can’t be reliably assessed and/or don’t correlate well with pain including
- Resting scapular position14–17
- Resting lumbar lordosis, cervical lordosis, thoracic kyphosis, and sacral angle18–25
2) Injury doesn’t always equal pain. We have lots of examples in the literature of people who have degenerated/bulging discs26, arthritis27, and partial rotator cuff tears28 yet they don’t have pain. Conversely many people can also have pain without injury.
3) We know in the literature that psychosocial factors can play a huge role in pain, particularly in chronic pain29,30.
4) The body can adapt to load and stress assuming that the stress is applied and progressed appropriately based on the status & demands of the individual31.
5) The amount of load/speed during a specific movement pattern is important. Many of the examples of biomechanical injury mechanisms above apply to high speed and/or high load activities. Obviously you don't have as much "movement leniency" deadlifting 700 lbs as you would bending over to pick up change. Ask any top level powerlifter where top level athletes squat 1000+ lbs and bench press 500-800+ lbs (depending on equipped or not) and they will tell you that there isn’t much margin for error with technique.
6) Our words can be more powerful than we think and when used incorrectly can create a nocebo effect (the opposite of placebo effect)32. When coaching movements & exercises it’s essential to use positive coaching & cueing for exercise & movement techniques to prevent kinesiophobia and fear avoidance. It's also important to instill positive beliefs in clients about their bodies.
So as you can see, biomechanical variables are still relevant to health & fitness professionals but they need to be looked at in light of both true biomechanical evidence (not just speculation) and the biopsychosocial model of pain.
To summarize the points in this article
1) Some biomechanical movement patterns can be mechanisms of (and risk factors for) injury
2) Many “biomechanical” variables can’t be reliably assessed and/or don’t correlate with pain
3) Injury doesn’t always equal pain. Psychosocial factors can play a huge role in pain.
4) Tissues can adapt to appropriately applied load.
5) Biomechanics and movement patterns apply more during high load & high speed situations than during low load situations.
6) When coaching & cueing movements & exercises use positive coaching to prevent nocebo effects and maximize your clients’ confidence in their bodies.
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