[Purpose] The aim of this study was to assess patients’ health-related quality of life, compare it with a healthy age-matched population, and examine associations between functional ability and quality of life among juvenile rheumatoid arthritis (JRA) patients. [Subjects and Methods] The study participants were 26 JRA patients and 25 controls. The Childhood Health Assessment Questionnaire and the Pediatric Quality of Life Inventory 4.0 Generic Core Scales were used to evaluate functional ability and health-related quality of life, respectively. [Results] Functional ability scores averaged 0.37 in the JRA group and 0.08 in the control group. There were significant between-group differences in functional ability scores in the overall cohort and in the subgroup of participants aged 14–16 years. Health-related quality of life scores were significantly lower in the JRA group than in the control group (68.39 vs. 85.17). In the JRA group, functional ability was statistically positively correlated with health-related quality of life. [Conclusion] We conclude that the mental state of adolescents with JRA affects their particular functional abilities. Subjects in the 14–16 age group who had a longer disease duration and higher difficulty scores showed a lower health-related quality of life than children in the other age groups.

[Purpose] This study was conducted to assess the physical fitness of children with juvenile rheumatoid arthritis (JRA). [Subjects and Methods] In total, 26 children with juvenile rheumatoid arthritis (JRA) and 25 healthy controls participated in this study. Using the physical fitness measurement instruments, the Inbody 720 and Quark b2, the elements of physical fitness that were assessed included muscular strength, muscular endurance, flexibility, lung capacity, and body composition. [Results] The results revealed significant differences in muscular strength, muscular endurance, lung capacity, body composition, functional ability, and health-related quality of life between the children with juvenile rheumatoid arthritis (JRA) and the control group. [Conclusion] These results suggested that children with juvenile rheumatoid arthritis (JRA) have inferior physical fitness when compared to healthy children. The present study was conducted to develop an accurate evaluation standard to assess the physical fitness of children with juvenile rheumatoid arthritis (JRA).