Estimating VO 2 max With the Timed Mile Run: An Updated Equation for Today's Youth

Background School‐based physical fitness testing (SB‐PFT) is an important tool to address youth physical inactivity. However, the widely used Fitnessgram equation that converts timed mile run performance into estimates of cardiorespiratory fitness (VO 2 max) may not be valid for today's diverse US adolescent population. This study evaluated its validity, developed updated prediction equations, and examined the effect of omitting sex and/or BMI. Methods A diverse sample of middle school students ( n = 177) provided demographic information and timed mile run data and completed lab‐based VO 2 max testing. Prediction accuracy for the Fitnessgram equation and newly‐developed equations was assessed using root mean square error (RMSE), Pearson's correlation, and sensitivity and specificity. Results In this diverse sample, all four new VO 2 max prediction equations outperformed the Fitnessgram equation, including equations excluding sex and/or BMI. Implications for School Health Policy, Practice, and Equity When evaluated on a diverse sample of adolescents, the Fitnessgram misclassifies many adolescents as being in the healthy fitness zone despite having cardiorespiratory fitness levels associated with elevated health risk. Conclusions The Fitnessgram VO 2 max prediction equation should be updated to reflect contemporary US demographics and schools' concerns about collecting BMI data.