Table 1. Descriptives and differences between low-, average- and high-YYIR1 performance groups and effect by 2- and 4-year follow-up subsamples.
Grand mean (n=21) low (n=7) average (n=7) high (n=7) MANOVA Cohen’s d
2-year follow-up Test Mean (SD) 95% CI Mean (SD) 95% CI Mean (SD) 95% CI Mean (SD) 95% CI F-value P-Value Low-Average Average-High Low-High
Age (y) 1 13.2 (.3) ± .1 13.2 (.2) ± .1 13.1 (.4) ± .2 13.2 (.2) ± .1 .376 .692 .00 .00 .11
2 14.2 (.3) ± .1 14.2 (.2) ± .1 14.1 (.4) ± .2 14.2 (.2) ± .1 .392 .682 .24 .24 .12
3 15.2 (.3) ± .1 15.2 (.2) ± .1 15.2 (.3) ± .1 15.2 (.2) ± .1 .345 .713 .24 .24 .24
Maturity OffSet (y) 1 -.85 (.51) ± .12 -.76 (.46) ± .18 -.60 (.49) ± .20 -1.20 (.43) ± .17 3.287 .061 .16 .09 .11
2 .14 (.72) ± .16 .27 (.58) ± .23 .44 (.76) ± .30 -.29 (.69) ± .28 2.181 .142 .08 .06 .08
3 1.17 (.70) ± .16 1.36 (.49) ± .20 1.45 (.85) ± .34 .70 (.52) ± .21 2.849 .084 .07 .03 .03
Stature (cm) 1 157.8 (6.5) ± 1.5 158.4 (3.6) ± 1.4 162.2 (6.5) ± 2.6 152.8 (5.6) ± 2.2 5.432 .014Σ .78 1.67 1.28
2 164.8 (7.5) ± 1.7 165.7 (3.8) ± 1.5 169.8 (7.8) ± 3.1 159.0 (6.4) ± 2.6 5.294 .016Σ .72 1.64 1.38
3 171.1 (6.5) ± 1.5 172.8 (2.9) ± 1.2 174.6 (7.3) ± 2.9 165.7 (5.2) ± 2.1 5.272 .016Σ .35 1.52 1.82
Body mass (kg) 1 46.0 (6.8) ± 1.6 48.2 (6.6) ± 2.6 49.3 (5.5) ± 2.2 40.5 (5.0) ± 2.0 4.863 .020Σ .20 1.81 1.42
2 52.7 (8.7) ± 2.0 54.6 (7.6) ± 3.0 57.0 (8.0) ± 3.2 46.2 (7.6) ± 3.0 3.592 .049Σ .33 1.50 1.19
3 59.3 (8.8) ± 2.0 62.5 (7.7) ± 3.1 63.5 (7.9) ± 3.2 52.0 (6.3) ± 2.5 5.312 .015Σ .14 1.74 1.61
YYIR1 (m) 1 1319(366) ± 83 886(114) ± 46 1357(100) ± 40 1714(145) ± 58 82.471 <.001# 4.74 3.10 6.86
2 1705(371) ± 85 1366(360) ± 144 1823(231) ± 92 1926(265) ± 106 7.386 .005# 1.63 .45 1.91
3 1823(427) ±97 1411(252) ± 101 1920(414) ± 166 2137(220) ± 88 10.296 .001# 1.60 .71 3.32
Grand mean (n=21) low (=7) average (n=7) high (n=7) MANOVA Cohen’s d
4-year follow-up Test Mean (SD) 95% CI Mean (SD) 95% CI Mean (SD) 95% CI Mean (SD) 95% CI F-value P-value Low-Average Average-High Low-High
Age (y) 1 12.2 (.3) ± .1 12.3 (.3) ± .2 12.2 (.4) ± .3 12.2 (.2) ± .2 .267 .769 .31 .00 .42
2 14.2 (.3) ± .1 14.3 (.3) ± .2 14.2 (.4) ± .3 14.2 (.2) ± .2 .244 .786 .31 .00 .42
3 16.2 (.3) ± .1 16.3 (.3) ± .2 16.3 (.4) ± .3 16.1 (.3) ± .2 .462 .638 .00 .61 .72
Maturity OffSet (y) 1 -1.72 (.34) ± .15 -1.54 (.33) ± .24 -1.83 (.38) ± .28 -1.80 (.28) ± .21 1.553 .239 .88 .10 .92
2 .28 (.61) ± .26 .57 (.50) ± .37 .04 (.83) ± .61 .23 (.36) ± .27 1.388 .275 .84 .32 .84
3 2.14 (.47) ± .20 2.28 (.23) ± .17 2.11 (.63) ± .47 2.04 (.52) ± .39 .431 .657 .39 .13 .64
Stature (cm) 1 150.7 (3.6) ± 1.5 152.5 (1.8) ± 1.3 149.9 (3.4) ± 2.5 149.7 (4.8) ± 3.6 1.408 .270 1.03 .05 .83
2 165.2 (5.2) ± 2.2 167.8 (4.6) ± 3.4 163.3 (5.6) ± 4.2 164.5 (4.9) ± 3.6 1.492 .251 .95 .25 .75
3 174.6 (3.9) ± 1.7 175.8 (4.1) ± 3.0 174.3 (2.8) ± 2.1 173.8 (4.8) ± 3.6 .497 .647 .46 .14 .48
Body mass (kg) 1 39.5 (4.4) ± 1.9 42.3 (5.0) ± 3.7 37.9 (4.2) ± 3.7 38.4 (2.8) ± 2.1 2.375 .121 1.03 .15 1.04
2 52.3 (7.2) ± 3.1 57.5 (8.7) ± 6.4 48.5 (5.7) ± 6.4 50.7 (3.6) ± 2.7 3.781 .043 1.32 1.10 .15
3 62.9 (5.1) ± 2.2 66.7 (6.5) ± 4.8 60.7 (3.0) ± 4.8 61.2 (3.1) ± 2.3 3.732 .044 1.28 0.18 1.17
YYIR1 (m) 1 1090(367) ± 157 703(224) ± 166 1063(128) ± 95 1503(83) ± 61 45.947 <.001# 2.13 4.41 5.12
2 1749(406) ± 174 1686(194) ± 144 1384(311) ± 230 2177(202) ± 150 19.281 <.001Σ 1.26 3.27 2.68
3 2175(338) ± 145 2126(373) ± 276 1966(218) ± 161 2434(248) ± 184 4.801 .021Σ .57 2.17 1.05
SD=standard deviation; CI=confidence interval;
# significant differences between all performance groups;
Low is different from Average;
Σ high is different from low and average