Supplementary Table 1.
Descriptive statistics (means, M, and standard deviations, SD) for chronological age (CA), predicted adult height, percentage of predicted adult height, estimated maturity status, body size, proportions and body composition, functional capacities, and coach evaluation of potential of select and non-select youth soccer players, results of MANOVAs, and results of MANCOVAs with age, age2 and the z-score for percentage of predicted adult height as covariates, and adjusted means (M) and standard errors (SE)
| Select (n = 18) | Non-Select (n = 13) | Results of MANOVA | Results of MANCOVA | Adjusted for Age and Maturity Status | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M | SD | M | SD | F | ηp2 | F | ηp2 | M | SE | M | SE | |
| Chronological Age, yrs | 14.6 | 0.5 | 14.3 | 0.5 | 2.48 | 0.08 | ||||||
| Pred adult height, cm | 179.6 | 4.7 | 178.7 | 4.9 | 0.23 | 0.01 | ||||||
| Height as% pred ad ht | 95.3 | 1.8 | 92.2 | 3.7 | 9.90** | 0.26 | ||||||
| Maturity Status | ||||||||||||
| Height,% pred ad ht, z | 0.60 | 0.45 | 0.12 | 0.59 | 6.69* | 0.19 | ||||||
| Biological age, yrs† | 15.1 | 0.6 | 14.3 | 1.0 | 9.09** | 0.24 | ||||||
| BA – CA, yrs | 0.55 | 0.50 | -0.01 | 0.64 | 7.36** | 0.20 | ||||||
| Size, Proportions, Composition: | ||||||||||||
| Height, cm | 171.1 | 5.1 | 164.7 | 8.6 | 6.57* | 0.19 | 0.01 | 0.00 | 168.5 | 1.1 | 168.3 | 1.4 |
| Weight, kg | 57.4 | 5.1 | 51.2 | 8.4 | 6.66* | 0.19 | 0.07 | 0.00 | 55.0 | 1.1 | 54.5 | 1.3 |
| Sitting height, cm | 88.6 | 3.3 | 83.6 | 6.3 | 8.38** | 0.22 | 0.58 | 0.02 | 87.0 | 0.9 | 85.8 | 1.1 |
| Estimated leg length, cm | 82.5 | 3.0 | 81.2 | 4.0 | 1.06 | 0.03 | 0.64 | 0.02 | 81.5 | 0.7 | 82.5 | 0.9 |
| Sit ht/ht ratio,% | 51.8 | 1.1 | 50.7 | 1.8 | 4.37* | 0.13 | 1.26 | 0.02 | 51.6 | 0.4 | 50.9 | 0.4 |
| Leg lt/sit ht ratio,% | 93.2 | 4.2 | 97.5 | 7.5 | 4.23* | 0.13 | 1.26 | 0.05 | 93.9 | 1.4 | 96.6 | 1.7 |
| Sum 4 skinfolds, mm | 29.9 | 5.2 | 37.1 | 18.3 | 2.52 | 0.08 | 0.83 | 0.03 | 30.9 | 3.1 | 35.7 | 3.7 |
| Fat mass,% | 14.8 | 1.8 | 15.6 | 3.6 | 0.61 | 0.02 | 0.01 | 0.00 | 15.2 | 0.6 | 15.1 | 0.7 |
| Muscle mass, kg | 45.5 | 5.0 | 40.9 | 6.8 | 4.76* | 0.14 | 0.01 | 0.00 | 43.5 | 1.1 | 43.7 | 1.3 |
| Functional Capacities: | ||||||||||||
| 5 m dash, s | 1.05 | 0.05 | 1.07 | 0.07 | 1.46 | 0.05 | 0.00 | 0.00 | 1.06 | 0.01 | 1.06 | 0.02 |
| 20 m dash, s | 3.06 | 0.13 | 3.26 | 0.19 | 11.13** | 0.28 | 2.37 | 0.08 | 3.11 | 0.03 | 3.19 | 0.04 |
| Agility, s | 12.63 | 0.54 | 12.80 | 0.44 | 0.88 | 0.03 | 0.03 | 0.00 | 12.72 | 0.12 | 12.68 | 0.14 |
| Vertical jump, cm | 52.0 | 8.6 | 40.5 | 8.3 | 14.04** | 0.33 | 5.74* | 0.18 | 50.7 | 2.1 | 42.2 | 2.5 |
| Sum R+L grip, kg | 73.6 | 8.0 | 56.5 | 15.0 | 16.86** | 0.37 | 5.37* | 0.17 | 70.7 | 2.6 | 60.5 | 3.2 |
| Yoyo shuttle run, m | 1713 | 584† | 1323 | 563 | 3.29 | 0.11 | 1.34 | 0.05 | 1643 | 126 | 1409 | 142 |
| Coach Evaluation of Potential: | ||||||||||||
| Technical skills | 3.17 | 0.79 | 3.00 | 0.71 | 0.37 | 0.01 | 2.55 | 0.09 | 3.30 | 0.18 | 2.82 | 0.22 |
| Tactical skills, attack | 3.72 | 0.83 | 2.62 | 0.51 | 18.26** | 0.39 | 13.88** | 0.35 | 3.73 | 0.18 | 2.60 | 0.22 |
| Tactical skills, defense | 2.78 | 0.94 | 2.69 | 0.85 | 0.07 | 0.00 | 0.22 | 0.01 | 2.67 | 0.23 | 2.85 | 0.28 |
| Creativity/decision skills | 3.50 | 0.71 | 2.77 | 0.60 | 9.13** | 0.24 | 9.75** | 0.27 | 3.56 | 0.17 | 2.69 | 0.20 |
| Usefulness in play | 3.44 | 1.34 | 2.69 | 0.63 | 3.52 | 0.11 | 1.41 | 0.05 | 3.35 | 0.26 | 2.83 | 0.31 |
| Overall potential†† | 16.61 | 3.74 | 13.77 | 1.79 | 6.39* | 0.18 | 5.59* | 0.18 | 16.67 | 0.76 | 13.69 | 0.91 |
*
p < 0.05,
**
p < 0.01.
†
n = 16.
††
sum of the five scores