Previous studies investigating the biomechanical factors associated with maximal countermovement jump height have typically utilised cross-sectional data. An alternative but less common approach is to use pre-to-post training change data, where the relationship between an improvement in jump height and a change in a factor is examined more directly. Our study compared the findings of these approaches. Such an evaluation is necessary because cross-sectional studies are currently a primary source of information for coaches when examining what factors to train to enhance performance. The countermovement jump of forty four males was analysed before and after an eight week training intervention. Correlations with jump height were calculated using both cross-sectional (pre-training data only) and pre-to-post training change data. Eight factors identified in the cross-sectional analysis were not significantly correlated with a change in jump height in the pre-to-post analysis. Additionally, only six of eleven factors identified in the pre-to-post analysis were identified in the cross-sectional analysis. These findings imply that: (a) not all factors identified in a cross-sectional analysis may be critical to jump height improvement, and (b) cross-sectional analyses alone may not provide an insight into all of the potential factors to train to enhance jump height. Coaches must be aware of these limitations when examining cross-sectional studies to identify factors to train to enhance jump ability. Additional findings highlight that while exercises prescribed to improve jump height should aim to enhance concentric power production at all joints, a particular emphasis on enhancing hip joint peak power may be warranted.