Response to criticisms of the 20 m shuttle run test: deflections, distortions and distractions

Correspondence to Dr Grant R Tomkinson, Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks 58202, USA; [email protected]

In their editorial, Armstrong and Welsman¹ suggest that the 20 m shuttle run test (20mSRT) (mis)represents and (mis)interprets youth cardiorespiratory fitness (CRF), and potentially (mis)informs health promotion and clinical practice. Their main arguments are: (a) the 20mSRT only provides an estimate of CRF (ie, peak V˙ O₂) and (b) estimates are ratio-scaled (ie, expressed relative to body mass). In this response we provide several reasons, rooted in evidence, which refute their interpretation of our work.

CRF measures the body’s capacity to deliver and utilise oxygen for energy transfer to support muscle activity during physical activity.² The 20mSRT provides a simple, single measure that assesses the integrated responses of the physiological systems’ ability to perform progressive aerobic exercise. Unfortunately, it does not provide specific information on the function or contribution of specific systems that can be obtained from a gas analysed peak ${\displaystyle \dot{V}}$ O₂ test. The 20mSRT is a good measure of functional exercise capacity that authentically imitates youth physical activities (eg, running, agility) in a natural setting. At the individual level, the 20mSRT is a true indicator of peak ${\displaystyle \dot{V}}$ O₂ (absolute or relative to body mass) because peak ${\displaystyle \dot{V}}$ O₂ is achieved at the end of a maximal performance.³ While it is widely accepted that gas-analysed peak ${\displaystyle \dot{V}}$ O₂ is the criterion physiological measure of CRF, other factors also contribute to CRF (eg, mechanical efficiency, ${\displaystyle \dot{V}}$ O₂ kinetics, etc). 20mSRT performance, as well as treadmill running/walking, is also affected by physical (eg, excess adiposity) and psychosocial (eg, self-efficacy, motivation) factors.

Evidence supports the use of the 20mSRT in childhood and adolescence as a powerful marker of...