TABLE 3 Odds Ratios for Injury and Acute and Serious Overuse Injuries: Univariate and Multivariate Models" Univariate Model Multivariate Model Age Age and Hours Injured (all types) vs uninjured Age 1.23 (1.17-1.31) Weekly sports hours 1.06 (1.03-1.08) Weekly hours in organized sports:free play >2:1 1.30 (1.02-1.67)d 1.04 (1.01-1.06) 1.14 (0.87-1.50) Weekly organized sports hours >age Degree of sports specialization Acute vs overuse injury Age Weekly sports hours 1.59 (1.17-2.16) 1.42 (1.20-1.69) 1.30 (1.10-1.54) 1.27 (1.07-1.52) 1.08 (1.01-1.16)d 1.01 (0.99-1.03) Weekly hours in organized sports/free play >2:1 0.73 (0.54-0.98)d 1.11 (1.03-1.20)d 0.66 (0.48-0.89) Degree of sports specialization 0.89 (0.74-1.08) 0.87 (0.72-1.06) 0.58 (0.42-0.80) 0.88 (0.73-1.07) Serious overuse vs overuse injury Age 1.15 (1.05-1.25) Weekly sports hours 1.06 (1.03-1.09) 1.04 (1.01-1.06) Weekly hours in organized sports/free play >2:1 1.87 (1.26-2.76) 1.70 (1.13-2.55) Weekly organized sports hours >age 2.07 (1.40-3.05) Degree of sports specialization 1.50 (1.20-1.88) 1.42 (1.13-1.79) 1.36 (1.08-1.72) "Models were adjusted for age and hours training in sports. Values are reported as odds ratio (CI). Bolded values indicate statistical sig- nificance (P < .05). 'P < .001. 'P < .01. dp < .05. "Based on sports specialization score (out of 3). Degree Moderate High TABLE 4 Odds Ratios for Degree of Sports Specialization and Level of Injury (vs Uninjured)" Injured 1.44 (1.04-1.98)d 1.58 (1.11-2.24)d Overuse Injury 1.22 (0.85-1.75) 1.50 (1.01-2.22)d Serious Overuse Injury 2.04 (1.18-3.51) 2.25 (1.27-3.99) Acute Injury 1.52 (1.01-2.29)d 1.19 (0.75-1.89)" "Models were adjusted for age and hours training in sports. Values are reported as odds ratio (CI). Bolded values indicate statistical sig- nificance (P < .05). Low degree = reference. "Sports specialization criteria: year-round training (>8 mo), choosing a main sport, and quitting all other sports to focus on 1 main sport (low meets 0 or 1 criterion, moderate = 2, high = 3). "Includes all overuse injuries (ie, serious and nonserious). dp < .05. "P=.291. fp < .01. "P