Table 1:
Demographic and anthropometric characteristics of throwers and their controls a
| Characteristic | PRE |
PERI |
POST-EARLY |
POST-MID |
POST-LATE |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Controls | Throwers | Controls | Throwers | Controls | Throwers | Controls | Throwers | Controls | Throwers | |
| n | 10 | 22 | 9 | 16 | 9 | 14 | 13 | 14 | 10 | 24 |
| Demographics | ||||||||||
| Age (yr) | 10.5 ± 1.6 | 10.0 ± 1.1 | 14.2 ± 1.0 | 13.8 ± 1.5 | 17.5 ± 1.1 | 17.3 ± 1.4 | 20.1 ± 2.0 | 19.6 ± 2.1 | 27.5 ± 3.4 | 28.1 ± 2.3 |
| Maturity offset (yr) | −2.9 ± 0.9 | −3.1 ± 0.7 | 0.5 ± 0.8 | 0.6 ± 1.1 | 3.6 ± 0.7 | 3.2 ± 0.7 | 6.2 ± 1.7 | 6.0 ± 2.0 | 13.9 ± 3.2 | 14.5 ± 2.3 |
| Estimated age of peak height velocity (yr) | 13.4 ± 0.9 | 13.1 ± 0.5 | 13.8 ± 0.5 | 13.4 ± 0.8 | 13.9 ± 1.1 | 14.1 ± 1.0 | 13.9 ± 2.0 | 13.6 ± 1.1 | 13.6 ± 1.1 | 13.6 ± 1.2 |
| Age started throwing (yr) | — | 4.6 ± 0.7 | — | 4.8 ± 0.9 | — | 5.3 ± 0.9 | — | 5.5 ± 1.0 | — | 5.1 ± 1.2 |
| Playing time (hrs/wk) | — | 5.1 ± 3.1 | — | 5.0 ± 2.4 | — | 6.7 ± 1.9 | — | 6.7 ± 1.8 | — | —b |
| Throws per week (#/wk) | — | 245 ± 180 | — | 245 ± 180 | — | 322 ± 176 | — | 302 ± 161 | — | —b |
| Years throwing (yr) | — | 5.2 ± 1.3† | — | 8.1 ± 1.9† | — | 12.0 ± 1.5† | — | 14.1 ± 2.4† | — | 22.9 ± 2.7† |
| Whole-body anthropometry | ||||||||||
| Height (m) | 1.45 ± 0.13 | 1.41 ± 0.06 | 1.68 ± 0.06 | 1.59 ± 0.10* | 1.77 ± 0.09 | 1.79 ± 0.05 | 1.81 ± 0.07 | 1.78 ± 0.07 | 1.86 ± 0.07 | 1.86 ± 0.07 |
| Mass (kg) | 39.8 ± 9.5 | 39.4 ± 13.3 | 57.5 ± 12.5 | 51.8 ± 13.9 | 70.8 ± 11.7 | 75.6 ± 11.0 | 69.0 ± 9.5 | 76.1 ± 9.9 | 88.4 ± 17.0 | 97.9 ± 9.0* |
| BMI (kg/m2) | 18.7 ± 2.4 | 19.6 ± 6.3 | 20.1 ± 2.9 | 20.2 ± 3.9 | 23.4 ± 3.4 | 22.6 ± 3.7 | 21.6 ± 2.2 | 23.2 ± 2.3 | 25.7 ± 4.7 | 28.3 ± 2.6* |
| BMC (kg)c,d | 0.90 ± 0.19 | 0.92 ± 0.14 | 1.55 ± 0.21 | 1.56 ± 0.38 | 2.51 ± 0.43 | 2.57 ± 0.47 | 2.79 ± 0.46 | 2.88 ± 0.47 | 3.35 ± 0.54 | 3.63 ± 0.43 |
| Lean mass (kg)c | 23.7 ± 6.6 | 22.2 ± 3.4 | 35.0 ± 7.3 | 33.5 ± 10.4 | 50.3 ± 7.9 | 53.6 ± 7.3 | 53.8 ± 7.9 | 58.7 ± 5.7 | 55.7 ± 19.4 | 69.6 ± 6.6* |
| Fat mass (%)c | 29.2 ± 8.7 | 28.2 ± 5.6 | 22.7 ± 7.6 | 25.9 ± 11.3 | 19.3 ± 6.0 | 19.2 ± 6.2 | 15.3 ± 4.6 | 15.7 ± 5.0 | 24.2 ± 7.3 | 22.4 ± 3.8 |
| Regional anthropometry | ||||||||||
| Spine aBMD (g/cm2)c,e | 0.66 ± 0.06 | 0.65 ± 0.07 | 0.81 ± 0.07 | 0.81 ± 0.17 | 1.04 ± 0.16 | 1.07 ± 0.12 | 1.06 ± 0.11 | 1.17 ± 0.14* | 1.17 ± 0.11 | 1.23 ± 0.11 |
| Hip aBMD (g/cm2)c,e | 0.78 ± 0.07 | 0.79 ± 0.07 | 0.96 ± 0.08 | 0.97 ± 0.18 | 1.14 ± 0.21 | 1.16 ± 0.11 | 1.07 ± 0.10 | 1.23 ± 0.14* | 1.13 ± 0.11 | 1.31 ± 0.11* |
a
Data are mean ± SD (except for frequencies)
b
POST-LATE consisted of professional baseball players. They did not complete the throwing questionnaire
c
Obtained via dual-exergy x-ray absorptimometry
d
Values corrected for height
e
Values corrected for whole-body lean mass
*
p < 0.05, as determined by independent sample t-test (controls vs. throwers within maturity group)
†
p < 0.05 vs. all other maturity groups, as determined by one-way ANOVA followed by Tukey pairwise comparisons