John Cairney

Objectives Reliable measurements of health‐related fitness—cardiorespiratory endurance, muscular endurance, muscular strength, body composition, and flexibility—are imperative for understanding and tracking health‐related fitness from the preschool age. This study aimed to examine the test–retest reliability of field‐based (i.e., sit and reach [standard and back‐saver], standing long jump, grip strength); and laboratory‐based (i.e., Bruce Protocol Treadmill Test, Wingate Anaerobic Test) assessments of health‐related fitness in preschool aged children (4–5 years). Methods Forty‐two typically developing children participated in both assessment time points separated by 2–3 weeks. All fitness assessments were administered individually and repeated in the same order by the same assessor. Heteroscedasticity was examined for each parameter. Intraclass correlation coefficients were calculated to assess test–retest reliability. Results All parameters were homoscedastic. Test–retest reliability for the field‐based tests and Bruce Protocol Treadmill Test parameters were moderate to good. Test–retest reliability for the Wingate Test parameters were good to excellent for maximum pedal rate, peak power, and peak power/kg; mean power and fatigue measured at 10 and 30 s demonstrated moderate to excellent test–retest reliability. Conclusion The standard sit and reach, grip strength, and short‐term muscle power from the Wingate test are reliable assessments of health‐related fitness in preschool‐aged children.