#64: Is measuring strength useful? With Tim Cook

 Jared is joined by Tim Cook who is Senior Lecturer in Physiotherapy at the University of Chichester, Advanced Physiotherapy Practitioner in the NHS, and doctoral researcher to discuss their new paper with Prof. Jeremy Lewis in the Journal of Manual & Manipulative Therapy: "Rethinking strength testing in rotator cuff-related shoulder pain: a clinical tradition that lacks muscle."

Tim explains what pushed him to question routine strength testing in busy clinical practice, despite guidelines recommending it, and the pair dig into whether weakness is a cause of shoulder pain, a consequence of it, or something else altogether. They look at what subacromial anaesthetic injection studies reveal about pain versus true force output, and Tim reframes the classic "weak and painful shoulder" as the "flexible but painful shoulder," drawing parallels to other oversimplified clinical narratives like posture and core stability.

They also make the case for when strength testing can still earn its keep; patient engagement, expectation violation, building confidence, and sporting or return-to-performance populations such as ACL limb symmetry index, before turning to Goodhart's Law and the risk of chasing the test rather than the outcome, and why isolated isometric tests may not translate to real-world, endurance-based shoulder tasks. Tim closes out with an update on his PhD: a reliability RCT on strength and pain-free assessment currently in press, and an upcoming scoping review on the proposed mechanisms of exercise for RCRSP.

Key resources

Cook, T., Lewis, J., & Powell, J. (2026). Rethinking strength testing in rotator cuff-related shoulder pain: a clinical tradition that lacks muscle. Journal of Manual & Manipulative Therapy, 34(3), 193–198. https://doi.org/10.1080/10669817.2026.2663623

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Jared on Instagram: @‌shoulder_physio

Jared on X: @‌jaredpowell12

Tim on Instagram: @Timcookphysio

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