Muscle synergy asymmetry between the affected and unaffected limbs during the stance phase in unilateral flatfoot.
Jianqi Pan, Zixiang Gao, Zhanyi Zhou and 5 others
PMID 42069611WHAT IT FOUND
People with one flat foot showed different muscle coordination patterns on the affected side compared to the unaffected side.
The affected limb relied more on the inner calf muscle, while the unaffected limb relied more on the front shin muscle. Both sides maintained similar overall stability.
Key findings
01The affected side showed significantly higher weight for the lateral gastrocnemius and erector spinae, while the unaffected side showed higher weight for the rectus femoris.
02Coordination analysis revealed the unaffected side was dominated by the first synergy module (linked to the front shin muscle), whereas the affected side was dominated by the second synergy module (linked to the inner calf muscle).
03Despite these internal differences, both sides exhibited a similar number of muscle synergy modules and maintained a stable, in-phase coordination pattern during walking.
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 cross-sectional, so it cannot show how these muscle patterns change over time or with treatment. The analysis was limited to the stance phase of normal walking and may not apply to running or high-intensity activities. The link between these muscle coordination changes and actual clinical outcomes like pain or injury risk is theoretical and was not measured directly. The participants were young adults (mean age 23.67) with unilateral flatfoot, so results may not generalize to older adults or those with bilateral flatfoot.
Declared interests
The study was funded by various Chinese government research programs and medical associations, including the National Key R&D Program of China and Ningbo Natural Science Foundation. No specific conflicts of interest regarding commercial entities were declared in the provided text.
The easy way to misread this
Do not assume that the observed muscle reorganization is a direct cause of pain or injury, nor that it is necessarily harmful. The study found that the nervous system adapts to maintain stability, and the link to clinical symptoms was not tested.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →