This investigation aimed to employ novel analyses to longitudinal jump testing data gathered from competitive weightlifters to identify how certain biomechanical and performance characteristics obtained from the countermovement jump (CMJ) relate to changes in weightlifting performance over time and if they can differentiate higher and lower performers. A linear mixed-effect model was used to assess and compare the ability of countermovement jump height and net-impulse to predict Sinclair weightlifting total. CMJ force-time waveforms were compared in cross-sectional and repeated measures analyses to distinguish the force application patterns of higher-performing weightlifters and if they change over extended periods of training. It was found that both jump height and net impulse were significant predictors of Sinclair weightlifting total; however, likely due to changes in body mass within individuals over time, net impulse was a better predictor. The primary differentiator between higher and lower-performing weightlifters within the countermovement jump was the magnitude of force produced during the propulsive phase. No changes to the athlete’s force-time waveforms were observed across three testing sessions separated each by a year. Over the three testing sessions, no significant change in jump height was found; however, net impulse increased over time. The findings of this dissertation demonstrate that countermovement jump net impulse is a beneficial metric to monitor in competitive weightlifters as it demonstrated the capacity to predict changes in weightlifting performance, differentiated levels of performers, and changes over extended periods of training.