Background: Field-based fitness assessments are time-and cost-efficient. However, no studies to date have reported the predictive value of field-based musculoskeletal fitness assessments in preschoolers. The purpose of this study was to determine the validity of two field assessments to predict peak muscle power in preschool-aged children.Methods: Four-hundred nineteen 3-to 5-year olds participated (208 girls, 211 boys; mean age: 4.5±0.9 years). Peak power (PP) was evaluated using a modified 10-second Wingate protocol as the criterion standard. Standing long jump was measured in inches to the back of the heel using a 2-footed takeoff and landing. Shuttle run time was measured using a shuttle run protocol, that required children to sprint 50 feet (15.2m), pick up a small block and sprint back, with time measured to the closest millisecond. Regression modeling was used to calculate the predictive power of each field-based measurement, adjusting for weight (kg), age and sex.Results: Both standing long jump distance and shuttle run time were significantly correlated with PP (r=0.636, p<.001 and r=-0.684, p<.001 respectively). Linear regression analysis determined that a child's PP can be predicted from the child's weight, age and sex and either standing long jump or shuttle run time (adjusted R 2 = 0.79, p<.001 and 0.81, p<.001, respectively).
Conclusion:The standing long jump and the BOT-2 shuttle run are both significant predictors of peak muscle power in preschool children. Either measure can be used as a cost and time efficient estimate of musculoskeletal fitness in preschoolers.