Causal mechanisms of a scapular stabilization intervention for patients with subacromial pain syndrome: a secondary analysis of a randomized controlled trial.
Gisele Harumi Hotta, Rafael Krasic Alaiti, Daniel Cury Ribeiro and 2 others
PMID 35642020WHAT IT FOUND
Adding scapular stabilization exercises to a strengthening program did not reduce pain or disability in people with subacromial shoulder pain.
The extra exercises did not change scapular movement, position, or muscle strength, so the proposed mechanism for their benefit was not supported.
Key findings
01The addition of scapular stabilization exercises had no effect on pain intensity or shoulder disability compared to strengthening alone.
02The intervention did not influence the proposed mechanisms: scapular motion, scapular position, or periscapular muscle strength.
03While muscle strength was associated with disability, these causal links were unstable and the study was underpowered to detect mediation effects.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was underpowered for the mediation analysis, meaning it might have missed small or moderate causal effects. The analysis relied on univariate models for each mediator, which may not capture the complex interplay between movement and strength. Sensitivity analyses showed that the findings regarding disability were unstable and potentially biased by unmeasured confounders. Scapular movement was measured with an inclinometer, which the authors acknowledge is challenging and may not fully capture dynamic scapular dyskinesis.
The easy way to misread this
Do not conclude that scapular stabilization exercises are ineffective for all patients. This study tested adding them to a strengthening program for a specific condition (SAPS) and found no additional benefit or mechanism change. It does not prove that scapular-focused interventions have no place in other shoulder conditions or when used differently.