Normative values of hand grip and pinch strength in children and adolescents aged 3 to 17 years in Beijing and Tianjin Municipalities of China and their associations with body composition

Skeletal muscle plays major roles in metabolism, and it is important to assess the muscle function development in children during childhood. Hand grip and pinch strength are used as indicators of musculoskeletal function in children. The aim of this study was to establish normative values for hand grip and pinch strength in children and adolescents aged 3 to 17 years in Beijing and Tianjin Municipalities of China. This study also investigated the associations between grip and pinch strength and body composition. This cross-sectional study included 4699 children and adolescents aged 3 to 17 years in Tianjin and Beijing between 2022 and 2024. We measured hand grip strength using the Hand Dynamometer, pinch strength using the digital pinch gauge, and body composition using multifrequency bioelectrical impedance analysis. The LMS (lambda-mu-sigma) method was used to construct growth reference charts and smooth the percentile curves of grip strength, pinch strength, and body composition indices. Partial Spearman correlation analyses were performed to assess the correlation between grip and pinch strength and body composition index. Grip and pinch strength increased with age, and boys demonstrated higher values than girls across all age groups. There was a statistically significant correlation between grip and pinch strength and body composition indices in most age groups (P < 0.05). Fat-free mass index (FFMI) and muscle mass index (MMI) were found to have significantly stronger correlations with grip and pinch strength in boys than in girls (grip strength in overall ages: FFMI, 0.857 vs. 0.710, P < 0.0001; MMI, 0.854 vs. 0.696, P < 0.0001; pinch strength in overall ages: FFMI, 0.835 vs. 0.694, P < 0.0001; MMI, 0.832 vs. 0.681, P < 0.0001). Normative values for hand grip and pinch strength in children and adolescents aged 3 to 17 years in Beijing and Tianjin municipalities of China were established, which can help pediatric clinicians compare their patients’ measurements with normative values and assess the musculoskeletal and hand function of patients. The findings may not be generalizable to all children in China and that multicenter studies are needed to confirm these results. Establishing current and comprehensive normative data on grip and pinch strength is imperative for the assessment of muscular strength, but research among children is still largely lacking. Muscle strength is associated with height, weight and gender in childhood, but the association with body composition is not clear. This study established normative values for hand grip and pinch strength in children and adolescents aged 3 to 17 years in Beijing and Tianjin municipalities of China. These findings could provide comprehensive data on grip and pinch strength, which could help pediatric clinicians compare their patients’ measurements with normative values. Our results indicated that grip and pinch strength increase with age in childhood, and were significantly associated with fat mass index, fat-free mass index, and muscle mass index in most age groups. Sex differences in the associations between grip and pinch strength and body composition should be considered in child growth.