What a Biomechanical Assessment Reveals That an MRI Can't

What a Biomechanical Assessment Reveals That an MRI Can't

Image for illustrative purposes only
Bruno15 September 20253 min read

A scan can find a 'bulging disc' in a person with no pain, and find nothing in a person who can barely walk. Here's why imaging so often misleads — and what assessing movement reveals instead.

The imaging paradox

Modern imaging is extraordinary — and routinely misleading when used alone. Consider what the research shows about people with no pain whatsoever:

  • 37% of pain-free 20-year-olds have disc degeneration on MRI; by age 50, it's 80% (Brinjikji et al., 2015)
  • Up to 43% of asymptomatic adults over 40 show knee osteoarthritis features on MRI (Culvenor et al., 2019)
  • 34% of people with zero shoulder pain have rotator cuff abnormalities on MRI (Sher et al., 1995)

Read those numbers again. If we scanned everyone in Ipswich tomorrow, we'd find "abnormalities" in most of them — including the ones who feel perfectly fine. Structure and pain are far more loosely connected than most people believe.

What MRI can and cannot see

An MRI is a photograph of anatomy at rest, lying still in a tube. It answers: what does the tissue look like? It cannot answer:

  • How do you actually load that tissue when you walk, squat, run, land?
  • Which muscles fire, in what order, with what strength?
  • Where does force concentrate — and why there?
  • What compensation patterns has your body built around old injuries?

Yet those questions — not the photograph — usually hold the answer to persistent pain. Movement dysfunction predicts injury: Hewett et al. (2005) showed that valgus knee loading during landing prospectively predicted ACL injury in athletes. The problem existed in the movement before it ever appeared in the tissue.

What a biomechanical assessment measures

1. Video movement analysis

Gait, single-leg squat, step-down, landing — recorded and analysed frame by frame. Dynamic valgus, pelvic drop, trunk compensation and asymmetries appear on camera that no static examination detects.

2. Digital foot scan

Your feet are the interface with the ground. Arch behaviour, pressure distribution and left–right asymmetry quantified — not eyeballed.

3. Strength and control testing

Objective measures of the hip complex, quadriceps and calf: not just "how strong" but "how symmetrical" and "how controlled".

4. Infrared thermography

A physiological overlay: where is tissue actually inflamed or overloaded right now? Often the hot spot and the painful spot are different places — which is itself diagnostic gold.

When you do need imaging

To be clear: imaging is essential when red flags exist — significant trauma, suspected fracture, neurological signs, unexplained systemic symptoms. We refer for imaging when the clinical picture demands it. But for persistent, activity-related pain without red flags, assessing how you move almost always tells us more than another photograph of how you look inside.

Had a "normal" scan but the pain is still there? That's exactly the case a biomechanical assessment was made for. Book at Bruno Physical Rehabilitation, Ipswich.


References

  1. Brinjikji, W., Luetmer, P.H., Comstock, B. et al. (2015) 'Systematic literature review of imaging features of spinal degeneration in asymptomatic populations', American Journal of Neuroradiology, 36(4), pp. 811–816.
  2. Culvenor, A.G., Øiestad, B.E., Hart, H.F. et al. (2019) 'Prevalence of knee osteoarthritis features on magnetic resonance imaging in asymptomatic uninjured adults: a systematic review and meta-analysis', British Journal of Sports Medicine, 53(20), pp. 1268–1278.
  3. Sher, J.S., Uribe, J.W., Posada, A., Murphy, B.J. and Zlatkin, M.B. (1995) 'Abnormal findings on magnetic resonance images of asymptomatic shoulders', Journal of Bone and Joint Surgery, 77(1), pp. 10–15.
  4. Powers, C.M. (2010) 'The influence of abnormal hip mechanics on knee injury: a biomechanical perspective', Journal of Orthopaedic & Sports Physical Therapy, 40(2), pp. 42–51.
  5. Hewett, T.E., Myer, G.D., Ford, K.R. et al. (2005) 'Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study', American Journal of Sports Medicine, 33(4), pp. 492–501.

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