Are the five consecutive vertical jumps a reliable evaluation tool in Olympic and Paralympic sprinters? A cross-sectional study

This study aimed to verify the validity and reproducibility of five vertical jump test (5VJT) as a more specific vertical jump height evaluation tool in elite Olympic and Paralympic sprinters. The present research was a cross-sectional study. For this, 49 sprinters participated, being eighteen with visual impairment, ten with cerebral palsy, seven leg amputees, six arm amputees, and eight non-disabled athletes. The athletes performed squat jump (SJ), countermovement jump (CMJ) and 5VJT. To compare jump height, analysis of variance (ANOVA) was used, intraclass correlation test (ICC) to evaluate the reliability, Bland and Altman to verify agreement of each pair of methods used (CMJ vs 5VJT, SJ vs 5VJT) and Pearson correlation to ascertain the level of association (CMJ vs 5VJT, SJ vs 5VJT) and between the subgroups. The level of significance set for the study was P<0.05. Excellent reliability for each method (CMJ-ICC=0.96, 95% confidence interval [CI]:0.96-0.97; SJ-ICC=0.89, 95%CI:0.87-0.90; and 5VJT=ICC=0.98, 95%CI:0.97-0.98) was found and strong to very strong association between them were found in visual impairment athletes-5VJT with CMJ (r=0.85), SJ (r=0.93), leg amputees–5VJT with CMJ (r=0.84), SJ (r=0.92), arm amputees–5VJT with CMJ (r=0.90), SJ (r=0.93), cerebral palsy-5VJT with CMJ (r=0.90), SJ (r=0.95) and AB–5VJT with CMJ (r=0.80), SJ (r =0.92). The reproducibility of ground contact time (GCT) showed good reliability for visual impairment (ICC=0.68, CV=9.5%), leg amputee (ICC=0.72; CV=13.8%) and cerebral palsy (CCI=0.77; CV=14.8%). These data suggest that 5VJT can be reliably applied to measure jump height and GCT, providing practical information about two important variables to monitor muscle fatigue (i.e., jump height and contact time).