Modification of injury history as a risk factor for incident injury in North Carolina Youth Soccer Association Classic League soccer players fall (autumn) 1997 to spring 2000: adjusted incidence rate ratios stratified by playing level and playing position (n = 4453 athlete-seasons)
| One previous injuryversus none | Two or more previousinjuries versus none | |||
|---|---|---|---|---|
| IRR | 95% CI; CLR | IRR | 95% CI; CLR | |
| IRR, Incidence rate ratio; CLR, confidence limit ratio (upper confidence limit divided by lower confidence limit25). | ||||
| *Generalised Poisson regression model stratified by playing level and adjusted for sex, playing position, years of playing experience, years of Classic League soccer experience, and body mass index. | ||||
| †Generalised Poisson regression model stratified by playing position and playing level adjusted for sex, years playing experience, years of Classic League soccer experience, and body mass index. | ||||
| Adjusted estimates stratified by playing level* | ||||
| U12–14 | 2.47 | 1.67 to 3.64; 2.18 | 3.69 | 2.43 to 5.59; 2.30 |
| U15–18 | 2.44 | 1.79 to 3.35; 1.87 | 2.57 | 1.88 to 3.52; 1.88 |
| Adjusted estimates stratified by playing level and position† | ||||
| Among U12–14 | ||||
| Defenders | 1.28 | 0.71 to 2.28; 3.20 | 2.10 | 1.16 to 3.80; 3.27 |
| Goalkeepers | 1.84 | 0.91 to 3.76; 4.15 | 2.10 | 0.96 to 4.60; 4.80 |
| Forwards | 4.02 | 2.49 to 6.52; 2.62 | 5.21 | 3.14 to 8.64; 2.75 |
| Midfielders | 3.04 | 1.92 to 4.81; 2.50 | 5.41 | 3.35 to 8.75; 2.61 |
| Among U15–18 | ||||
| Defenders | 1.37 | 0.89 to 2.10; 2.36 | 1.55 | 1.01 to 2.37; 2.35 |
| Goalkeepers | 1.97 | 0.97 to 4.02; 4.16 | 1.55 | 0.76 to 3.17; 4.19 |
| Forwards | 4.31 | 2.62 to 7.08; 2.71 | 3.84 | 2.29 to 6.43; 2.81 |
| Midfielders | 3.25 | 1.96 to 5.39; 2.75 | 3.99 | 2.40 to 6.62; 2.76 |