The trend toward significance ( P = 0.05) despite substantial between-study variation suggests that core training may contribute to vertical jump performance enhancement, though the magnitude of improvement likely depends on training protocol design and athlete characteristics.
For sport-specific outcomes (k = 44), core training showed a moderate positive effect that approached but did not reach statistical significance (SMD = 0.62, 95% CI [− 0.08, 1.31], p = 0.084), with high heterogeneity (I 2 = 96.99%).
Statistical significance was notably affected by study removal, with p -values ranging from 0.10 to 0.15, suggesting borderline significance and limited robustness of findings for this outcome.
Despite common claims in practice, core training did not demonstrate significant improvements in maximal strength, and showed only near-significant effects on vertical jump performance while demonstrating limited or non-significant effects on speed, flexibility, change of direction, technical skills, and throwing performance.