The 10% rule: grip strength and hand dominance in a factory population.
Level 4 - case-series / case-control
Cross-sectional observational study of a single occupational cohort.
PubMed 24441784 · doi:10.3233/WOR-1997-8110
What was done
Researchers evaluated the validity of the clinical 10% rule for hand dominance and the effect of work experience on grip strength disparity in 124 factory workers in Indiana. Grip strength was measured with a Jamar dynamometer, and hand dominance was assessed using the Edinburgh Inventory.
What was found
The overall mean difference in grip strength between hands was 6.3079%. Percent difference in grip strength differed significantly based on years of work experience (P = 0.029). Right-handed and left-handed workers also differed significantly in their Edinburgh Inventory scores (P = 0.007).
Why it matters
Applying a generic 10% rule to assess impairment or normal function may be inaccurate for factory workers, as occupational hand use and tenure alter bilateral strength balance.
Limits
The study is limited to a single regional cohort of 124 factory workers. Specific occupational tasks, bilateral exposure details, and absolute strength values were not reported in the abstract.
Cited by
- contradicts A person's limb with greater gross force or strength is typically not the limb used for fine motor neural control.