An integrated force–time regression model for explaining weightlifting performance in youth weightlifters

Abstract Background Countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) force–time variables are commonly used to assess dynamic propulsive output, isometric force-production capacity, and explosive neuromuscular qualities related to weightlifting performance. Previous studies have usually examined CMJ and IMTP variables separately, leaving limited evidence on whether these measures can be integrated to explain sport-specific performance in youth weightlifters. This study examined the associations between CMJ- and IMTP-derived force–time variables and weightlifting performance, with PCA-derived hierarchical regression models used to evaluate the combined contribution of these assessments. Methods This cross-sectional study included 20 competitive youth weightlifters aged 13–18 years who completed CMJ and IMTP testing on dual force plates. Official competition results obtained within two weeks of laboratory testing were recorded for the snatch, clean and jerk, combined total, and Sinclair-adjusted combined total. Pearson correlation analysis with Benjamini–Hochberg adjustment, exploratory principal component analysis, and hierarchical multiple regression were used to examine the relationships between force–time characteristics and weightlifting performance. Results Pearson correlations showed that CMJ propulsive variables were strongly associated with weightlifting performance ( r = 0.708–0.842, adjusted p < 0.01), and IMTP peak vertical force showed strong associations across all outcomes ( r = 0.812–0.845, adjusted p < 0.001). RFD and early-phase impulse measures were not significantly associated with performance. PCA yielded one CMJ propulsive force–velocity component and two IMTP components representing force–impulse and peak-force and time-to-force characteristics. CMJ FAC1 alone explained a substantial proportion of variance across the performance outcomes, with R² values of 0.608–0.666. Adding IMTP FAC2 increased R² to 0.676–0.769, with further inclusion of IMTP FAC1 increasing R² to 0.749–0.778 across all outcomes. Conclusions Combining countermovement jump propulsive characteristics with isometric mid-thigh pull force–time dimensions provided a broader profile of current weightlifting performance in youth athletes. The combined assessment may help coaches and practitioners monitor strength-power characteristics, identify performance-associated neuromuscular qualities, and inform individualized training decisions in youth weightlifters.