Explaining High-Velocity Movement: Do Isometric or Heavy Strength Measures Show Stronger Associations? A Systematic Review and Meta-Analysis.

BACKGROUND: Establishing whether heavy dynamic or isometric strength measures better explain high-velocity performance is critical for guiding assessment strategies, prioritizing training targets, and optimizing the transfer of physical development to sport-specific outcomes. PURPOSE: The objectives of this investigation were to systematically review and meta-analyze the literature to compare heavy dynamic strength versus isometric strength measures in their associations with jump, sprint, and agility performance. METHODS: A systematic search was conducted in accordance with PRISMA guidelines through April 2025. Eligible studies reported correlations between strength measures and high-velocity performance outcomes. Correlation coefficients were converted to Fisher z values to standardize effects, which were then analyzed using a multivariate meta-analysis framework. RESULTS: Seven studies containing 22 heavy dynamic strength versus isometric strength comparisons and 299 participants were included in the final analysis. Heavy dynamic strength measures showed a small but significant overall advantage over isometric tests (z = 0.18, 95% CI [0.02 to 0.34]). By high-velocity task, fast strength (eg, measures derived from the countermovement jump) outcomes favored dynamic (z = 0.25, 95% CI [0.03 to 0.47]; I2 = 85.9%), while reactive strength (eg, drop jump reactive strength index) and change of direction/agility showed no differences, the latter with no heterogeneity (I2 = 0%). CONCLUSIONS: Heavy dynamic strength tests demonstrate a somewhat stronger association with high-velocity performance than isometric measures, with effects varying by outcome type. These findings support a multidimensional approach to athlete profiling and underscore the value of both dynamic and isometric strength assessments depending on the context.