Cooper's 12 Minute Run Systematically Underestimates VO2 max in Collegiate Team Sport Athletes: Validity and Classification Accuracy.

The Cooper 12-Minute Run Test (CT12) is widely used to estimate cardiorespiratory fitness (CRF), yet its validity in collegiate team-sport athletes remains uncertain. This study aimed to compare the CT12-estimated VO2 max with laboratory-measured VO2 max and evaluate CT12's accuracy in classifying CRF levels. Seventy-three varsity athletes (38% women; age 21.6 ± 2.8 y; BMI 23.5 ± 3.3 kg/m2) completed CT12 on a 400-m track and a ramp-incremental treadmill test with breath-bybreath gas analysis, 2-7 days apart in randomized order. VO2 max was classified by age/sex criteria. Agreement statistics included paired tests, Pearson correlation, Bland-Altman bias, and 95% limits of agreement (LOA), 95% confidence intervals (CI), and diagnostic indices (sensitivity, specificity, positive/negative predictive value) for detecting good, excellent, and superior CRF. Field (soccer/rugby) and court (futsal/handball) subgroups were analyzed. CT12 on average underestimated VO2 max by 6.0 mL(kg.min)-1 (p<0.001; r=0.69), with wide LOA: -19.8 to +7.9 mL(kg.min)-1. CT12's sensitivity to identify good or better CRF was low (58% [95% CI 45-69%]). However, it demonstrated superior specificity (86% [95% CI 60-96%]) and exhibited an excellent positive predictive value of 94% (95% CI 82-99%). Similar patterns were observed for classifications of excellent and superior CRF. We conclude that in collegiate team-sport athletes, CT12 underestimates VO2 max with substantial individual error. Nevertheless, a positive CT12 classification (good/excellent/superior) is trustworthy due to high specificity/PPV, whereas a negative result warrants further evaluation. These findings endorse CT12 as a practical screening instrument for elevated CRF levels, rather than a replacement for laboratory VO2 max when precise measurement is essential.