The 20 m shuttle run is not a valid test of cardiorespiratory fitness in boys aged 11-14 years.

OBJECTIVES

The 20 m shuttle run test (20mSRT) is used to estimate cardiorespiratory fitness (CRF) through the prediction of peak oxygen uptake ( ), but its validity as a measure of CRF during childhood and adolescence is questionable. This study examined the validity of the 20mSRT to predict peak .

METHODS

Peak was measured during treadmill running. Log-linear regression was used to correct peak for body mass and sum of skinfolds plus age. Boys completed the 20mSRT under standardised conditions. Maximum speed (km/h) was used with age to predict peak using the equation developed by Léger . Validity was examined from linear regression methods and limits of agreement (LoA). Relationships between 20mSRT performance and allometrically adjusted peak , and predicted per cent fat were examined.

RESULTS

The sample comprised 76 boys aged 11-14 years. Predicted and measured mass-related peak (mL/kg/min) shared common variance of 32%. LoA revealed that measured peak ranged from 15% below to 25% above predicted peak . There were no significant relationships (p>0.05) between predicted peak and measured peak adjusted for mass, age and skinfold thicknesses. Adjusted for body mass and age, peak was not significantly related (p>0.05) to 20mSRT final speed but a weak, statistically significant (r=0.24, p<0.05) relationship was found with peak adjusted for mass and fatness. Predicted per cent fat was negatively correlated with 20mSRT speed (r=-0.61, p<0.001).

CONCLUSIONS

The 20mSRT reflects fatness rather than CRF and has poor validity grounded in its flawed estimation and interpretation of peak in mL/kg/min.