Marked Differences in Lower-Limb Muscle Strength and Motor Performance Between Japanese and Chinese Children Aged 9-12: A Cross-National Study.

Abstract

Background: This study includes an investigation of lower-limb muscle strength and physical activity among children in Japan and China, with the aim of promoting children's health.

Methods: A total of 564 children (300 boys, 264 girls) aged 9-12 years from public primary schools in Tokyo, Japan, and Jiangxi Province, China, were included. Height, body weight (BW), hip adductor and abductor strength, and toe grip strength were measured. The side-step test (SST) and timed-up-and-go test (TUGT) were performed. Exercise habits were assessed via a questionnaire.

Results: Japanese students produced significantly higher values than Chinese students in SST (23.3-37.1%) and TUGT (6.6-8.0%), except among 11-year-old girls. Japanese boys aged 10-11 and girls aged 10-12 had significantly greater hip adductor strength/BW and toe grip strength/BW. Japanese students also showed significantly higher hip abductor strength/BW at all ages. Additionally, the proportion of children engaging in vigorous-intensity physical activity (VPA) was significantly higher in Japanese boys aged 10-12 and girls aged 9-11 than in their Chinese counterparts.

Conclusions: Chinese students showed diminished lower-limb strength and agility compared to Japanese students. These findings highlight the importance of promoting outdoor play, particularly VPA, to improve children's physical fitness and health, especially in China.