Association of drop vertical jump displacement with select performance variables

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Drop vertical jumps (DVJs) simulate run-up loading, crucial for assessing explosive power.
• Key performance variables include ground contact time (GCT), reactive strength index (RSI), eccentric utilization ratio (EUR), and elasticity index (EI).
• Understanding the reliability and validity of these metrics is essential for accurate performance evaluation.

Purpose of the Study:

• To assess the reliability and precision of GCT, RSI, and EUR in trained individuals performing DVJs.
• To examine the association between these performance variables and DVJ displacement.
• To determine if GCT and EUR represent unique performance characteristics distinct from jump height.

Main Methods:

• Trained male and female participants performed DVJs.
• Measurements included ground contact time (GCT), reactive strength index (RSI), and eccentric utilization ratio (EUR).
• Statistical analyses involved intraclass correlation coefficients (ICCs) for reliability and Pearson correlations for associations with DVJ displacement.

Main Results:

• GCT, RSI, and EUR data demonstrated high reliability (ICC ≥ 0.70) and precision (CV% ≤ 15.0).
• Correlations with DVJ displacement were low for GCT, moderate for RSI, and negligible for EUR.
• EUR and EI were found to be redundant measures, with only EUR findings reported.

Conclusions:

• GCT and EUR are reliable and precise metrics for DVJs, likely reflecting unique performance aspects unrelated to jump displacement.
• RSI's association with DVJ displacement may be influenced by displacement being part of its calculation.
• These findings aid in selecting appropriate metrics for evaluating explosive performance in DVJs.