Predicting Health‐Related Physical Fitness in Healthy Korean Adults: National Fitness Award 2015‐2019

Abstract

Introduction Technological advances in sports science have provided athletes, coaches, and researchers with economic, efficient, and reliable means to record health-related data through wearable devices worn on the wrist. The connected gains of novel analytical techniques, reliable and portable devices, and comprehensive software programs suggest that health promotion research will increase in the future. This study examined developing a multiple linear regression model to estimate health-related physical fitness using easy-to-measure dependent variables in healthy Korean adults. Methods The dependent variables (e.g., sex, age, body mass index, and percent body fat) were measured in healthy Korean adults (total n = 319,643; male n = 147,600; female n = 172,043) for estimating health-related physical fitness. Health-related physical fitness includes grip strength, flexibility (sit and reach), muscle endurance (sit-ups), and cardiorespiratory fitness (VO2max). The health-related physical fitness estimation multiple linear regression model was developed using the stepwise technique. In addition, we rigorously conformed to the basic assumptions of the regression model: linearity, independence, continuity, normality, homoscedasticity, autocorrelation, and outliers. The outlier data in the multiple regression model were identified and deleted when the absolute value of the studentized residual was ≥ 2. Results The regression model's coefficient of determination for the grip strength (adjusted R2: 0.870), muscle endurance (adjusted R2: 0.751), and cardiorespiratory fitness (adjusted R2: 0.885) was significantly high. However, the coefficient of determination of the regression model for the flexibility was low (adjusted R2: 0.298). The multiple regression model was developed using sex, age, body mass index, and percent body fat to estimate the health-related physical fitness in healthy Korean adults. The coefficient of determination of grip strength, muscle endurance, and cardiorespiratory fitness in the developed multiple regression models was shown to be very high. Conclusion Our findings suggest that easy-to-measure dependent variables predict grip strength, muscle endurance, and cardiorespiratory fitness in a healthy adult.