Injury incidence rates and unadjusted incidence rate ratios (n = 5139 athlete-seasons) and generalised adjusted incident rate ratios (n = 4453 athlete-seasons) for risk of incident injury in North Carolina Youth Soccer Association Classic League soccer players fall (autumn) 1997 to spring 2000
| Variable | No of incident injuries | Athlete-exposures | Rate per 1000 athlete-exposures | 95% CI* | Unadjusted rate ratio | 95% CI*; CLR | Adjusted rate ratio† | 95% CI; CLR |
|---|---|---|---|---|---|---|---|---|
| Incidence rate and unadjusted rate ratio used generalised Poisson regression model. | ||||||||
| *95% confidence interval computed under standard large sample Poisson assumptions.22 | ||||||||
| †Generalised Poisson regression model rate ratio estimates are adjusted for all other covariates with complete data (n = 4453). | ||||||||
| CLR, Confidence limit ratio (upper confidence limit divided by lower confidence limit25); BMI, body mass index (kg/m2). | ||||||||
| Previous injury | ||||||||
| None (ref) | 187 | 75 683 | 2.5 | 2.1 to 3.0 | ||||
| One | 294 | 50 512 | 5.9 | 5.3 to 6.5 | 2.37 | 1.92 to 2.94; 1.53 | 2.57 | 2.00 to 3.29; 1.64 |
| Two or more | 306 | 44 429 | 6.9 | 6.1 to 7.7 | 2.79 | 2.25 to 3.46; 1.54 | 2.97 | 2.28 to 3.86; 1.69 |
| Sex | ||||||||
| Male (ref) | 467 | 109 957 | 4.3 | 3.9 to 4.7 | ||||
| Female | 320 | 60 666 | 5.3 | 4.7 to 6.0 | 1.24 | 1.06 to 1.45; 1.37 | 1.03 | 0.86 to 1.23; 1.43 |
| Level | ||||||||
| U12–14 (ref) | 271 | 76 510 | 3.6 | 3.1 to 4.1 | ||||
| U15–18 | 516 | 94 114 | 5.5 | 5.0 to 6.0 | 1.54 | 1.30 to1.82; 1.40 | 1.33 | 1.08 to 1.65; 1.54 |
| Position | ||||||||
| Midfield (ref) | 241 | 58 937 | 4.1 | 3.6 to 4.7 | ||||
| Defender | 252 | 45 062 | 5.6 | 4.9 to 6.4 | 1.36 | 1.12 to 1.65; 1.47 | 1.23 | 1.00 to 1.51; 1.51 |
| Forward | 202 | 48 720 | 4.2 | 3.6 to 4.9 | 1.01 | 0.83 to 1.24; 1.50 | 1.01 | 0.82 to 1.23; 1.50 |
| Goalkeeper | 69 | 13 801 | 5.0 | 3.9 to 6.5 | 1.21 | 0.91 to 1.63; 1.80 | 1.00 | 0.73 to 1.37; 1.88 |
| Soccer experience | ||||||||
| 0–2 years (ref) | 27 | 3626 | 7.5 | 5.2 to 1.09 | ||||
| 3–6 years | 152 | 39 372 | 3.9 | 3.2 to 4.7 | 0.52 | 0.34 to 0.78; 2.29 | 0.52 | 0.34 to 0.80; 2.32 |
| 7–10 years | 396 | 87 149 | 4.6 | 4.1 to 5.1 | 0.61 | 0.42 to 0.90; 2.17 | 0.62 | 0.42 to 0.92; 2.19 |
| 11–17 years | 178 | 34 085 | 5.2 | 4.4 to 6.1 | 0.69 | 0.46 to 1.04; 2.25 | 0.62 | 0.40 to 0.97; 2.42 |
| Classic League soccer experience | ||||||||
| 0 years (ref) | 99 | 17 094 | 5.8 | 4.7 to 7.3 | ||||
| 1–4 years | 481 | 110 539 | 4.4 | 4.0 to 4.8 | 0.75 | 0.60 to 0.94; 1.59 | 0.65 | 0.50 to 0.83; 1.65 |
| 5–8 years | 166 | 34 082 | 4.9 | 4.1 to 5.7 | 0.83 | 0.64 to 1.09; 1.72 | 0.53 | 0.39 to 0.72; 1.88 |
| 9–12 years | 18 | 4904 | 3.6 | 2.2 to 5.9 | 0.61 | 0.36 to 1.05; 2.96 | 0.35 | 0.20 to 0.62; 3.17 |
| BMI quartiles | ||||||||
| 11.00–17.76 (ref) | 157 | 43 474 | 4.0 | 3.4 to 4.6 | ||||
| 17.77–19.53 | 184 | 37 342 | 4.4 | 4.0 to 4.8 | 1.10 | 1.03 to 1.19; 1.16 | 1.00 | 0.92 to 1.08; 1.18 |
| 19.54–21.12 | 166 | 33 699 | 4.9 | 4.4 to 5.3 | 1.22 | 1.05 to 1.41; 1.34 | 0.99 | 0.84 to 1.17; 1.40 |
| 21.13–32.53 | 170 | 33 348 | 5.4 | 4.7 to 6.1 | 1.35 | 1.08 to 1.68; 1.56 | 0.99 | 0.77 to 1.27; 1.66 |