Validity of the 16-metre PACER and six-minute walk test in adults with Down syndrome

Abstract

Purpose: The purpose was to establish criterion-related validity of the 16-metre PACER and six-minute walk distance (6MWD) tests to VO2 peak as well as predictors of VO2 peak in adults with Down syndrome (DS). Methods: Adults with DS (24 males and 19 females) aged 18-50 years performed the three aerobic tests on non-consecutive days during a one-week period. To assess validity, peak oxygen uptake was measured directly on a motorized treadmill. Pearson-product moment correlations were performed. Predictors of VO2 peak were assessed with a stepwise multiple regression analysis. Agreement between PACER and VO2 peak was assessed by Bland-Altman plot. Results: Linear regression revealed that the PACER (R2 = 0.86) and the 6MWD (R2 = 0.75) were significantly related to VO2 peak (p < 0.05). Both the 16-metre PACER and the 6MWD significantly correlated with VO2 peak for adults with DS. The relationship was stronger for the 16-metre shuttle run test (r = 0.87) than the 6MWD (r = 0.78). The correlation between VO2 peak and both field tests, controlling for age, gender and BMI, remained significant (r > 0.7; p < 0.05). PACER, 6MWD and BMI are significant predictors of VO2 peak (p < 0.05). Conclusion: The 16-metre PACER and 6MWD are valid field tests for predicting aerobic capacity in adults with DS