Estimation of aerobic fitness from 20-m multistage shuttle run test performance.

BACKGROUND Aerobic fitness (VO(2)max) is a key component of youth fitness testing. Criterion-referenced (CR) assessments are used in FITNESSGRAM(®) to assess health risk. PURPOSE The purpose of this study was to develop and cross-validate regression models to estimate VO(2)max from Progressive Aerobic Cardiovascular Endurance Run (PACER) 20-m shuttle run performance in boys and girls aged 10-16 years. Several previously published PACER models were also cross-validated. A secondary purpose was to examine the CR validity of the models. METHODS PACER performance and VO(2)max were assessed in a sample of 244 participants. The sample was randomly split into validation (n=174) and cross-validation (n=70) samples. The validation sample was used to develop the regression models to estimate VO(2)max from PACER, BMI, gender, and age. CR validity was evaluated by comparing classification of the prediction models with classification by the criterion of measured VO(2)max. RESULTS For the Quadratic Model, the multiple correlation between measured and estimated VO(2)max was 0.75, and the SE of estimate (SEE) was 6.17 mL/kg/min. Similar accuracy was found for Linear Model 2 (R=0.74; SEE=6.29 mL/kg/min). Accuracy of these models was confirmed on the cross-validation and total samples. Cross-validation demonstrated that the Quadratic Model and Linear Model 2 were slightly more accurate than previous PACER models. Evidence of CR validity for the newly developed models was of moderate levels. CONCLUSIONS The Quadratic Model and Linear Model 2 provide valid estimates of VO(2)max and compare favorably to previous models. The CR validity evidence for the Quadratic Model and Linear Models developed in this study was slightly better than for the other models examined.