Introduction
Injury epidemiology in football
Interlimb asymmetries
Functional jump tests
Prevention screening
Aims of the study
Methods
Participants
Team | N | Mass (kg ± SD) | Height (m ± SD) | BMI (kg/m2 ± SD) | Limb length (cm ± SD) |
---|---|---|---|---|---|
U11 | 15 | 35.2 ± 4.9 | 1.5 ± 0.1 | 16.5 ± 1.4 | 82.5 ± 4.3 (Dom) – 82.5 ± 4.4 (N-Dom) |
U12 | 18 | 38.0 ± 3.7 | 1.5 ± 0.0 | 17.8 ± 1.2 | 80.1 ± 3.3 (Dom) – 80.5 ± 3.2 (N-Dom) |
U13 | 19 | 48.4 ± 8.5 | 1.6 ± 0.1 | 18.6 ± 2.1 | 88.2 ± 6.0 (Dom) – 88.1 ± 5.8 (N-Dom) |
U14 | 19 | 56.5 ± 8.2 | 1.7 ± 0.1 | 20.1 ± 1.8 | 94.2 ± 4.7 (Dom) – 94.4 ± 5.1 (N-Dom) |
U15 | 19 | 63.3 ± 9.7 | 1.7 ± 0.1 | 20.9 ± 1.9 | 96.3 ± 4.6 (Dom) – 96.4 ± 4.7 (N-Dom) |
U16 | 21 | 67.8 ± 8.7 | 1.8 ± 0.1 | 21.7 ± 1.8 | 97.2 ± 6.3 (Dom) – 97.4 ± 6.3 (N-Dom) |
U17 | 18 | 71.2 ± 7.2 | 1.8 ± 0.1 | 22.7 ± 1.5 | 98.4 ± 3.9 (Dom) – 98.4 ± 3.9 (N-Dom) |
U19 | 17 | 72.8 ± 8.7 | 1.8 ± 0.1 | 22.1 ± 2.1 | 100.1 ± 5.2 (Dom) – 99.9 ± 5.4 (N-Dom) |
Testing procedures
Countermovement jump test (CMJ)
Jump for distance test (JFD)
Side hop test (SH)
Speedy jump test (SJ)
Statistical analysis
Results
Mean values
U11 | U12 | U13 | U14 | U15 | U16 | U17 | U19 | ||
---|---|---|---|---|---|---|---|---|---|
CMJ | Dom (cm) | 13.9 ± 2.6 | 15.0 ± 2.7 | 16.2 ± 2.2 | 19.4 ± 3.2 | 19.3 ± 3.0 | 21.0 ± 3.5 | 21.6 ± 3.5 | 21.9 ± 3.1 |
N‑Dom (cm) | 14.3 ± 3.2 | 15.7 ± 2.7 | 17.1 ± 2.8 | 19.2 ± 3.2 | 20.5 ± 3.0 | 20.9 ± 3.1 | 22.5 ± 4.9 | 23.5 ± 3.6 | |
LSI (%) | 103.4 ± 19.9 | 105.9 ± 15.4 | 106.2 ± 13.2 | 99.9 ± 14.6 | 107.6 ± 14.3 | 100.4 ± 14.1 | 104.3 ± 13.5 | 107.9 ± 16.3 | |
JFD | Dom (cm) | 120.6 ± 10.3 | 120.8 ± 15.2 | 127.3 ± 15.4 | 146.1 ± 18.2 | 145.6 ± 16.0 | 154.0 ± 13.0 | 152.9 ± 11.3 | 154.7 ± 10.2 |
N‑Dom (cm) | 117.1 ± 11.2 | 124.3 ± 11.5 | 127.4 ± 16.9 | 143.4 ± 17.8 | 153.6 ± 18.2 | 152.8 ± 19.5 | 161.1 ± 14.9 | 161.0 ± 15.7 | |
LSI (%) | 97.5 ± 11.1 | 103.9 ± 12.4 | 100.6 ± 12.3 | 98.8 ± 12.3 | 106.1 ± 13.7 | 99.7 ± 9.2 | 104.6 ± 8.5 | 103.3 ± 10.6 | |
SH | Dom (n) | 31.1 ± 6.1 | 50.0 ± 7.8 | 49.9 ± 12.6 | 55.4 ± 10.9 | 60.3 ± 7.1 | 65.5 ± 7.6 | 64.2 ± 9.6 | 66.5 ± 6.9 |
N‑Dom (n) | 33.6 ± 8.6 | 53.1 ± 7.4 | 52.6 ± 8.4 | 55.8 ± 7.6 | 61.3 ± 7.0 | 67.0 ± 6.1 | 66.6 ± 7.8 | 67.5 ± 8.8 | |
LSI (%) | 109.8 ± 27.2 | 107.1 ± 11.2 | 111.2 ± 31.4 | 105.1 ± 30.6 | 102.3 ± 12.8 | 103.5 ± 8.8 | 105.2 ± 15.8 | 100.9 ± 8.9 | |
SJ | Dom (s) | 7.6 ± 0.9 | 7.2 ± 0.6 | 7.2 ± 0.8 | 6.8 ± 0.5 | 7.1 ± 0.6 | 6.7 ± 0.6 | 6.2 ± 1.0 | 6.7 ± 0.6 |
N‑Dom (s) | 7.8 ± 1.1 | 7.2 ± 0.7 | 7.7 ± 0.7 | 7.2 ± 0.8 | 7.3 ± 0.5 | 6.7 ± 0.6 | 6.6 ± 0.9 | 6.8 ± 0.8 | |
LSI (%) | 103.2 ± 15.8 | 101.1 ± 9.3 | 106.0 ± 10.2 | 105.2 ± 10.3 | 102.7 ± 7.2 | 100.3 ± 8.1 | 106.1 ± 9.1 | 102.6 ± 7.4 |
Analysis of variance
Test | Associations (ANOVA) | |||
---|---|---|---|---|
Df | F | Partial eta squared (ηp2) | Sig. | |
CMJ | ||||
Score | 1 | 8.638 | 0.059 | 0.004* |
Score ×Age | 7 | 0.985 | 0.048 | 0.445 |
Age | 7 | 20.492 | 0.510 | 0.000* |
JFD | ||||
Score | 1 | 2.289 | 0.018 | 0.133 |
Score × Age | 7 | 1.306 | 0.068 | 0.253 |
Age | 7 | 20.201 | 0.529 | 0.000* |
SH | ||||
Score | 1 | 8.802 | 0.062 | 0.004* |
Score × Age | 7 | 0.343 | 0.018 | 0.933 |
Age | 7 | 38.010 | 0.667 | 0.000* |
SJ | ||||
Score | 1 | 11.142 | 0.081 | 0.001* |
Score × Age | 7 | 0.614 | 0.033 | 0.743 |
Age | 7 | 6.902 | 0.276 | 0.000* |
Test | Associations (ANOVA) | |||
---|---|---|---|---|
Df | F | Mean Square | Sig. | |
CMJ | 7 | 0.769 | 175.379 | 0.614 |
JFD | 7 | 1.119 | 146.765 | 0.355 |
SH | 7 | 0.507 | 215.869 | 0.828 |
SJ | 7 | 0.869 | 84.290 | 0.533 |
Normal distribution, homogeneity of variances and correlation between age and performance
Test | Correlation | Shapiro–Wilk test | Normal distribution | Homogeneity of variances (Levene) | ||||
---|---|---|---|---|---|---|---|---|
Pearson | Sig. (2-tailed) | Statistic | Sig. (2-tailed) | Skewness | Kurtosis | Statistic | Sig. (2-tailed) | |
CMJ | ||||||||
Dom | 0.654 | 0.000* | 0.981 | 0.038** | 0.344 | −0.133 | 0.892 | 0.515 |
N‑Dom | 0.654 | 0.000* | 0.982 | 0.047** | 0.381 | −0.005 | 20.063 | 0.052 |
LSI | 0.042 | 0.616 | 0.985 | 0.115 | 0.303 | −0.046 | 0.972 | 0.454 |
JFD | ||||||||
Dom | 0.381 | 0.000* | 0.715 | 0.000** | −2.211 | 4.679 | 1.184 | 0.317 |
N‑Dom | 0.549 | 0.000* | 0.768 | 0.000** | −2.164 | 5.586 | 1.302 | 0.255 |
LSI | 0.096 | 0.276 | 0.659 | 0.000** | −2.325 | 5.137 | 0.494 | 0.837 |
SH | ||||||||
Dom | 0.553 | 0.000* | 0.908 | 0.000** | −1.244 | 1.853 | 1.174 | 0.322 |
N‑Dom | 0.510 | 0.000* | 0.902 | 0.000** | −1.407 | 2.917 | 0.494 | 0.838 |
LSI | −0.119 | 0.162 | 0.741 | 0.000** | −0.311 | 9.422 | 2.355 | 0.027*** |
SJ | ||||||||
Dom | −0.271 | 0.001* | 0.669 | 0.000** | −2.696 | 8.064 | 1.870 | 0.080 |
N‑Dom | −0.211 | 0.011* | 0.697 | 0.000** | −2.798 | 9.983 | 1.719 | 0.110 |
LSI | 0.021 | 0.807 | 0.605 | 0.000** | −2.651 | 6.432 | 1.756 | 0.102 |
U19 | U17 | U16 | U15 | U14 | U13 | U12 | |
---|---|---|---|---|---|---|---|
U11 | |||||||
CMJ | 0.000* | 0.000* | 0.000* | 0.000* | 0.000* | 0.190 | 0.916 |
JFD | 0.000* | 0.000* | 0.000* | 0.000* | 0.000* | 0.808 | 0.998 |
SH | 0.000* | 0.000* | 0.000* | 0.000* | 0.000* | 0.000* | 0.000* |
SJ | 0.006* | 0.000* | 0.000* | 0.362 | 0.025* | 0.945 | 0.312 |
U12 | |||||||
CMJ | 0.000* | 0.000* | 0.000* | 0.000* | 0.001* | 0.883 | – |
JFD | 0.000* | 0.000* | 0.000* | 0.000* | 0.000* | 0.959 | |
SH | 0.000* | 0.000* | 0.000* | 0.010* | 0.768 | 0.999 | |
SJ | 0.759 | 0.019* | 0.404 | 0.999 | 0.965 | 0.934 | |
U13 | |||||||
CMJ | 0.000* | 0.000* | 0.000* | 0.015* | 0.089 | – | – |
JFD | 0.000* | 0.000* | 0.000* | 0.000* | 0.003* | ||
SH | 0.000* | 0.000* | 0.000* | 0.004* | 0.644 | ||
SJ | 0.117 | 0.000* | 0.018* | 0.965 | 0.324 | ||
U14 | |||||||
CMJ | 0.014* | 0.091 | 0.647 | 0.999 | – | – | – |
JFD | 0.206 | 0.180 | 0.429 | 0.953 | |||
SH | 0.000* | 0.003* | 0.000* | 0.407 | |||
SJ | 0.999 | 0.284 | 0.973 | 0.904 | |||
U15 | |||||||
CMJ | 0.078 | 0.333 | 0.949 | – | – | – | – |
JFD | 0.820 | 0.815 | 0.979 | ||||
SH | 0.215 | 0.576 | 0.289 | ||||
SJ | 0.607 | 0.007* | 0.239 | ||||
U16 | |||||||
CMJ | 0.564 | 0.935 | – | – | – | – | – |
JFD | 0.999 | 0.999 | |||||
SH | 0.999 | 0.999 | |||||
SJ | 0.999 | 0.821 | |||||
U17 | |||||||
CMJ | 0.997 | – | – | – | – | – | – |
JFD | 0.999 | ||||||
SH | 0.997 | ||||||
SJ | 0.700 |