Cross Validation of the 20-m Shuttle Run Test for Children and Adolescents With Mental Retardation

We cross validated the 20-m shuttle run test of aerobic capacity in children and adolescents with mild and moderate mental retardation @lR) using the population specific formula of Femhall et al. (1998). Nine boys and 8 girls (age = 13.7 yr) completed a maximal treadmill protocol (measured .\iOtFk) and a 20-m shuttle run (predicted ~ 0 , ~ ~ ) . The measured peak oxygen consumption ( ~ 0 ~ ~ ) was 39.4 ml kg' min-'. The relationship between measured and predicted voZpeak w s r = .86 with an SEE of 6.2 ml kg1 mir-l. Multiple regression and Bland-Altman analyses showed that there was little bias, but the Bland-Altman analysis indicated highly variable limits of agreement (Bland &Altman1986). Thus, the traditional approach (regression analysis) to concurrent validity revealed that the 20-m shuttle run is a valid indicator of VO,@ in these participants. The accuracy of prediction (Bland & Altman, 1986), however, was lower than expected in a population without MR.