Table 2. Simple main effects of the swim speed and dv as discrete variables between tiers by sex, and between sexes by tiers. Boys Tier #1 vs Tier #2 Tier #1 vs Tier #3 Tier #2 vs Tier #3 Mean difference (95CI) p d [descriptor] Mean difference (95CI) p d [descriptor] Mean difference (95CI) p d [descriptor] Speed [m/s] 0.161 (0.131 to 0.190) <0.001 3.37 [very large] 0.354 (0.324 to 0.383) <0.001 6.52 [nearly perfect] 0.193 (0.163 to 0.223) <0.001 4.85 [nearly perfect] dv [%] 0.000 (-1.459 to 1.460) 1.000 0.00 [trivial] -0.902 (-2.361 to 0.557) 0.223 0.41 [small] -0.903 (-2.362 to 0.556) 0.223 0.45 [small] Girls Tier #1 vs Tier #2 Tier #1 vs Tier #3 Tier #2 vs Tier #3 Mean difference (95CI) p d [descriptor] Mean difference (95CI) p d [descriptor] Mean difference (95CI) p d [descriptor] Speed [m/s] 0.109 (0.079 to 0.138) <0.001 4.31 [nearly perfect] 0.256 (0.226 to 0.286) <0.001 4.64 [nearly perfect] 0.147 (0.118 to 0.177) <0.001 2.72 [very large] dv [%] 0.394 (-1.065 to 1.853) 0.594 0.15 [trivial] -1.973 (-3.432 to -0.514) 0.008 0.71 [moderate] -2.368 (-3.827 to -0.908) 0.002 1.02 [moderate] Tier Tier #1 – Boys vs Girls Tier #2 – Boys vs Girls Tier #3 – Boys vs Girls Mean difference (95CI) p d [descriptor] Mean difference (95CI) p d [descriptor] Mean difference (95CI) p d [descriptor] Speed [m/s] 0.156 (0.127 to 0.186) <0.001 3.37 [very large] 0.104 (0.075 to 0.134) <0.001 4.31 [nearly perfect] 0.059 (0.029 to 0.088) <0.001 0.82 [moderate] dv [%] -0.135 (-1.594 to 1.324) 0.855 0.05 [trivial] 0.259 (-1.200 to 1.718) 0.726 0.13 [trivial] -1.206 (-2.665 to 0.254) 0.104 0.51 [small] dv - intra-cyclic variations of horizontal speed; p – p-value; d – Cohen’s d [effect size descriptor].