Trends in gross body coordination and cardiorespiratory fitness-a hierarchical Bayesian Analysis of 35 000 2nd Graders

Objective A negative decline of motor competence in children has been observed over the last decades. Though most studies derive their inferences from only two distant points in time and thus neglect to investigate the variability of the temporal trends. Methods Between the year 2000 and 2011, 35 018 second graders performed the Korperkoordinationstest fur Kinder (KTK), consisting of four items (WB, HH, JS, and MS) and a six minute run test (6MRT). A hierarchical Bayesian regression model with varying intercepts and temporal trends was fitted to the data. Age, sex, and BMI categories were included as input variables. The outcome variables were z-standardized to the initial cohort. Results In all four KTK items, we observed a yearly decline of -0.020 (95% UI -0.038 to -0.001) for WB, -0.054 (95% UI -0.071, -0.037) for HH, -0.028 (95% UI -0.045 to -0.012) for JS and -0.088 (95% UI -0.108 to -0.067) for MS. For the 6MRT, no trend was identified. Overweight and obese children showed a disadvantage in all tests scores. Negative time interactions were observed for overweight and obese children in HH and JS. A substantial between-city variation for all temporal trends was observed. The predictive validation for all models but MS was successful. Conclusion A general negative decline was confirmed for coordinative abilities but not in cardiorespiratory fitness. For all outcome variables, a substantial between-city variation was observed, highlighting the importance of environmental factors in motor development. Overweight and obese children demonstrated an urgent need for action.