Muscular grip strength normative values for a Korean population from the Korea National Health and Nutrition Examination Survey, 2014–2015

Introduction
Muscle weakness is linked to a range of adverse health outcomes across the lifespan including mortality, morbidity, and disability. Because lifestyles and body composition are quite different between Western and Asian countries, there is an urgent need to establish normative grip strength values for individuals of Asian descent. This study presents normative data for hand grip strength in a Korean population-representative sample.
Methods
A sample of 11,073 individuals (age 10–80 years) was included from the Sixth Korea National Health and Nutrition Examination Survey, 2014–2015. Isometric grip strength was assessed using a handheld dynamometer. Relative grip strength was calculated as the maximum absolute grip strength divided by body mass index. Means, standard error, and quintiles for grip strength and relative grip strength were analyzed per 5-year age group for each sex. To create growth charts for grip strength and relative grip strength, parametric quantile regression was used.
Results
In males, absolute grip strength increased quickly starting from 10 years of age until approximately 20 years of age. In females, there was gradual growth until approximately 15 years of age. Grip strength continued to increase until a peak between ages 30 and 39 years, and then declined from midlife onwards in both sexes. Our data showed that the prevalence of weak grip strength increased rapidly in late adult life based on a T-score of -2 standard deviations below the sex-specific peak mean (equivalent to 33 kg in males and 20 kg in females). Approximately 20% of subjects had weak grip strength at age 65–69 years.
Conclusion
This was the first study to establish normative reference values for grip strength across the lifespan in a Korean population aged 10–80 years. Percentiles of grip strength will inform clinical assessments and will help identify thresholds for the identification of muscle weakness.