Figure 3
From: Physical fitness of primary school children differs depending on their timing of school enrollment
Cross-sectional development in five physical fitness components for keyage children (blue symbols) and OTK children (red symbols). The horizontal line marks 9.0 years (i.e., typical age boundary between keyage and OTK third-graders). Panel (a) shows the cross-sectional developmental rates according to the chronological age. Panel (b) shows the cross-sectional developmental rates according to the proxy for biological age. Data come from 108,295 keyage and 26,540 OTK third-graders reported in Fühner et al.23 and were z-transformed. Points are binned child means. Z-scores for children between the ages 7.0 and 8.0 years and for children between 9.5 and 10.0 years were aggregated. Endurance = cardiorespiratory endurance (i.e., 6-min-run test), Coordination = star-run test, Speed = 20-m linear sprint test, PowerLOW = lower limbs muscle power (i.e., standing long jump test), PowerUP = upper limbs muscle power (i.e., ball-push test). For coordination and speed, scores were converted from seconds to meters/seconds (i.e., pace scores; star-run test = 50.912 [m]/time [s]; 20-m linear sprint test = 20 [m]/time [s]). For all physical fitness tests, a larger z-score indicates a better physical fitness.
