Optimal Drop Heights for Determining Reactive Strength Performance in Youth—Is 1 Drop Height Sufficient to Generate Trustworthy Conclusions for Training Practice?

Abstract

This study critically examines the suitability of using a single drop height to assess the reaction strength index in trained and active participants, a key component of athletic performance. Using a cross-sectional design, 377 trained (n = 163) and active (n = 214) participants aged 14–18 years performing drop jumps from 4 different heights (24, 32, 40, and 48 cm) were studied. The primary aim was to explore the individual differences in reaction strength index at these heights and to assess whether a single height can reliably represent stretch-shortening cycle capabilities. While the repeated measures analysis of variance did not reveal any significant differences, the Bland–Altmann analysis revealed significant individual discrepancies between the performance of the drop heights, resulting in a mean absolute error of 32.1 and a mean absolute percentage error of 20.6%. These results strongly suggest that a single drop height is not sufficient to determine performance in the stretch-shortening cycle. This has important practical implications as it can lead to underestimates of performance trends. The study advocates the inclusion of a range of drop heights in routine testing to accurately measure reactive power and thus improve the effectiveness of individualized training programs for young athletes/active youth.