The Accuracy of the Progressive Aerobic Cardiovascular Endurance Run to Estimate Aerobic Fitness in Youth

The FITNESSGRAM’s Progressive Aerobic Cardiovascular Endurance Run (PACER) test is a commonly used field test to estimate peak oxygen uptake (VO_2peak) in youth. However, little research has been conducted to determine the influence of weight status on the accuracy of the equations used to estimate VO_2peak. Purpose: To assess the agreement between VO_2peak measured using indirect calorimetry during the PACER and estimated VO_2peak in normal weight and overweight youth and to determine the influence of weight status on the accuracy of estimated VO_2peak in 10-15 year old youth. Methods: The study included 101 participants that were classified as normal weight (n=78) or overweight (n=23) according to BMI percentiles for age and sex. Participants completed the PACER, a progressive, multistage, 20-meter shuttle run to volitional exhaustion. VO_2peak was measured during the PACER test using a portable gas analysis system (Oxycon Mobile, CareFusion, Inc.). Estimated VO_2peak values were calculated based on PACER performance using the Leger et al. and Mahar et al. equations. Paired samples t-tests were used to determine if significant differences existed between estimated and measured VO_2peak. Independent t-tests were performed to compare the normal weight and overweight groups. Accuracy was determined using Bland-Altman plots. Results: The Leger et al. (44.3 +4.6 ml/kg/min) and Mahar et al. (46.8 +4.8 ml/kg/min) estimated values were significantly lower than measured VO_2peak (49.0 +8.7 ml/kg/min) in the normal weight group. There were no significant differences between measured VO_2peak (38.8 +7.1 ml/kg/min) and predicted values (40.5 +2.5 and 38.2 +6.1 ml/kg/min; Leger et al. and Mahar et al., respectively) for the overweight group. For the normal weight group, the standard error of the estimate (SEE) was Leger 5.44 ml/kg/min (Leger) and 5.33 ml/kg/min (Mahar). The SEE was 5.77 ml/kg/min (Leger) and 4.54 ml/kg/min (Mahar) for the overweight participants. Conclusions: It appears that the prediction of VO_2peak from either equation based on PACER performance varies among weight status group and may be inaccurate for normal weight youth, but acceptable for overweight youth.