Inter and intra-session reliability and validity of the Performanz JumpR device for measuring different jump performances in young male soccer players

This study aimed to determine the inter- and intra-session reliability and validity of the Performanz JumpR device for measuring different jump performances in young male soccer players. Fifty-four young male soccer players (mean age: 15.90 ± 0.70) completed three maximal squat jumps (SJ), countermovement jumps (CJ), and 40 cm drop jumps (DJ) over two separate days. These jumps were assessed using both a contact mat and the Performanz JumpR device. The different jump performances were compared using several statistical methods, including the intraclass correlation coefficient (ICC = 2.1), Bland-Altman plots, Pearson product-moment correlation coefficient ( r), Cronbach’s alpha (α), and the coefficient of variation (CV). Results showed almost perfect agreement between the Performanz JumpR device and the contact mat for SJ, CJ, and 40 cm DJ values, with jump heights and peak powers yielding ICC values between 0.98 and 0.99 during both assessment sessions. Additionally, the Pearson product-moment correlation coefficient showed an almost perfect correlation between the measurements from the Performanz JumpR device and the contact mat for SJ, CJ, and 40 cm DJ values, with r values ranging from 0.96 to 0.99 during the first and second assessment sessions. The Performanz JumpR device demonstrated very good intra-session reliability for the three jumps in each set, with the following results: SJ (jump height, α = 0.98, CV = 2.02; peak power, α = 0.99, CV = 1.35), CJ (jump height, α = 0.98, CV = 2.20; peak power, α = 0.99, CV = 1.46), and 40 cm DJ (jump height, α = 0.97, CV = 2.61; peak power, α = 0.99, CV = 1.79). When analyzing the inter-session reliability of the Performanz JumpR device and contact mat across all players, almost identical correlations were observed between the two instruments for SJ, CJ, and 40 cm DJ regarding jump heights and peak powers ( r = 0.96–0.99) between the first and second assessment sessions. Additionally, the Bland-Altman plots demonstrated an almost agreement, with a systematic bias identified between the Performanz JumpR device and the contact mat for SJ, DJ, and 40 cm DJ values ( p < 0.01). Overall, the Performanz JumpR device provided reliable inter-session and intra-session data, as well as valid measurements for maximal jump height and peak power during SJ, CJ, and 40 cm DJ in young male soccer players.