Normative Reference Values of Physical Fitness Levels in Koreans: Results from the National Fitness Award Project (2017-2019)

PURPOSE: This study aimed to develop age-and sex-specific smoothed percentile curves for fitness items using LMS methods in Koans aged 13–85 years or older. METHODS: A total of 559,430 individuals aged 13-85 years or older (adolescents: 13-18 years, adults: 19-64 years; older adults: >65 years) participated in the National Fitness Award (NFA) project in 2017, 2018, and 2019 in Korea. In this study, the results of body composition (body fat percent), muscle strength (absolute handgrip strength and relative handgrip strength), and flexibility (sit and reach) tests performed by adolescents, adults, and older adults, were analyzed. Cardiorespiratory fitness (20-m PACER, VO2max) was performed only by adolescents and adults. Percentile curves of fitness items smoothed by age-and sex-specific variables were calcu-lated for fit using the LMS method. RESULTS: Percentile curves for each age-and sex-specific group were presented for each physical fitness component. Percent body fat in men and women increased from the age of 25 and 30 years, respectively. Flexibility showed a tendency to decrease sharply after the age of 65 and 70 years in men and women, respectively. Muscle strength decreased gradually after 40 years, and sharply after 60 years. Cardiorespiratory fitness tended to decrease from the age of 25 years in men and from 19 years in women. CONCLUSIONS: The NFA project dataset provided the opportunity to establish normative values for fitness items in Korean men and women aged 13-85 years or older. The use of the LMS method enabled factoring age in the analysis. Normative reference values of fitness items can be used to interpret individuals’ fitness levels during the everyday practice of fitness and/or in clinical settings.