Is grip strength a predictor for total muscle strength in healthy children, adolescents, and young adults?

The primary purpose of this study was to examine whether grip strength is related to total muscle strength in children, adolescents, and young adults. The second purpose was to provide reference charts for grip strength, which could be used in the clinical and research setting. This cross-sectional study was performed at primary and secondary schools and the University of Applied Sciences. Three hundred and eighty-four healthy Dutch children, adolescents, and young adults at the age of 8 to 20 years participated. Isometric muscle strength was measured with a handheld dynamometer of four muscle groups (shoulder abductors, grip strength, hip flexors, and ankle dorsiflexors). Total muscle strength was a summing up of shoulder abductors, hip flexors, and ankle dorsiflexors. All physical therapists participated in a reliability study. The study was started when intratester and intertester reliability was high (Pearson correlation coefficient >0.8). Grip strength was strongly correlated with total muscle strength, with correlation coefficients between 0.736 and 0.890 (p < 0.01). However, the correlation was weaker when controlled for weight (0.485-0.564, p < 0.01). Grip strength is related to total muscle strength. This indicates, in the clinical setting, that grip strength can be used as a tool to have a rapid indication of someone's general muscle strength. The developed reference charts are suitable for evaluating muscle strength in children, adolescents, and young adults in clinical and research settings.