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.

Implications for Rehabilitation

• The 16-metre PACER and 6MWD tests are safe and feasible for use in adults with DS.

• Both tests are valid indicators of cardio-respiratory fitness as assessed by moderate-to-strong coefficients of determination and correlation coefficients.

• Both field tests along with BMI are predictors of aerobic capacity.

Keywords:

• Aerobic capacity
• functional ability
• intellectual disability
• PACER
• six-minute walk test
• VO₂ peak

Disclosure statement

The authors declare no conflicts of interest.