## 3 Results  
Overall passing performance (PC\({}_{\rm P1}\)) based on all tests was significantly positively associated with age (R\({}^{2}\) = 0.42, t = 10.67; \(p\) < 0.001), height (R\({}^{2}\) = 0.19, t = 6.13; \(p\) < 0.001) and mass (R\({}^{2}\) = 0.23, t = 6.90, \(p\) < 0.001) (Figure 2). A player's age and size index (ASI) was also significantly positively associated with their overall passing performance (R\({}^{2}\) = 0.31, t = 8.29, \(p\) < 0.001) (Table 1). All individual passing tests were significantly repeatable (Supplementary Table S3) and performance significantly varied among the passing tests (df = 5; F = 432.2; \(p\) < 0.001) (Table 2). Differences in performance among the tests that were identified with [PERSON]'s  
Figure 2: Relationship between overall passing performance (PC\({}_{\rm P1}\)) and age (**A**), height (**B**), mass (**C**) and ASI (**D**). ANOVA were examined using the Games-Howell post hoc test (Table 2). Players completed the most passes on average in test 5 (27.4 \(\pm\) 5.38 passes) where they turned through 45 degrees when passing to a board 4 m from the player. In the identical test over 8 m (test 6), the number of passes completed was significantly lower (12.4 \(\pm\) 3.2 passes). Players completed 22.8 \(\pm\) 4.6 passes when turning through 90 degrees and the rebound board was 4 m from the player (test 1), which was significantly greater than the same test over 8 m (12.5 \(\pm\) 2.4 passes). In addition, players completed 19.6 \(\pm\) 4.1 passes when turning through 135 degrees and the rebound board was 4 m from the player (test 3), which was significantly greater than the same test over 8 m (11.1 \(\pm\) 2.7 passes). Significant positive correlations were found among all paired tests, ranging from 0.39 to 0.59 (Supplementary Table S4). Significant differences among the cohorts were found on all tests, indicating that each test could discriminate among different age groups (Table 3). On all tests, the older cohorts tended to perform better than the younger cohorts (Table 3). \begin{table}
\begin{tabular}{l c c c} \hline \hline  & **Intercept** & \(\beta\) & **R\({}^{2}\)** \\ \hline Age (years) & \(-37.867\)\({}^{*}\) & 9.515 \({}^{*}\) & 0.42 \\ Height (cm) & \(-82.415\)\({}^{*}\) & 1.103 \({}^{*}\) & 0.19 \\ Mass (kg) & 35.093 \({}^{*}\) & 1.152 \({}^{*}\) & 0.23 \\ ASI & 102.83 \({}^{*}\) & 12.038 \({}^{*}\) & 0.31 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Independent effects of age, height, mass and ASI on overall passing performance (PC\({}_{\rm Pl}\)). Each pairing of intercept and \(\beta\) represents a separate linear model. Passing performance (PC\({}_{\rm Pl}\)) was square transformed [y = (x + 10)\({}^{2}\)] prior to analyses. \({}^{*}p\) < 0.001. \begin{table}
\begin{tabular}{l c c} \hline \hline  & **n** & **Mean \(\pm\) SD** \\  & **(Passes/Test)** \\ \hline Test 1 & 161 & 22.84 \(\pm\) 4.60 \\ Test 2 & 164 & 12.45 \(\pm\) 2.38 \\ Test 3 & 159 & 19.58 \(\pm\) 4.08 \\ Test 4 & 164 & 11.07 \(\pm\) 2.70 \\ Test 5 & 165 & 27.36 \(\pm\) 5.38 \\ Test 6 & 164 & 12.39 \(\pm\) 3.18 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Performance on each passing test for the elite academy. Differences among tests identified with [PERSON]’s ANOVA and the Games–Howell post hoc test.