Effects of vertically- and horizontally-orientated plyometric training on physical performance: a meta-analytical comparison

Background In accordance with the principle of training specificity, adaptations to vertically or horizontally orientated plyometric training (VPT, HPT) directly transfer to athletic tasks that are carried out in the same direction as they are performed. Objectives The objective of this systematic review and meta-analysis was to determine the relative effect of VPT and HPT on both vertical and horizontal measures of physical performance. Data Sources Google Scholar, CrossRef, Microsoft Academic, PubMed, Web of Science, Scopus. Study Eligibility Criteria To qualify for inclusion in the meta-analysis, studies must have included a plyometric training intervention that compared jumps executed in a vertical direction [i.e. countermovement jump (CMJ)] to jumps executed in a horizontal direction (i.e. standing horizontal jump). Study Appraisal and Synthesis Methods We used the inverse-variance random effects model for meta-analyses. Effect sizes, calculated from measures of horizontally or vertically orientated performance, were represented by the standardised mean difference and presented alongside 95% confidence intervals (CI).