Relationship between reactive strength variables in horizontal and vertical drop jumps.

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Reactive strength is crucial for athletic performance.
• Drop jumps (DJ) are commonly used to assess and train reactive strength.
• Understanding the relationship between vertical and horizontal DJ is important for training program design.

Purpose of the Study:

• To investigate the relationship between reactive strength in vertical and horizontal drop jumps (DJ).
• To assess the reliability of vertical and horizontal DJs.
• To determine how contact time influences jump performance in both types of DJs.

Main Methods:

• 28 participants with jump training experience performed vertical and horizontal drop jumps from a 0.4m box.
• Measured variables included contact time, jump height, jump distance, and reactive strength index (RSI).
• Intrasubject reliability was assessed using typical error measurements (TEMCV%) and intraclass correlations (ICCs).

Main Results:

• Both vertical and horizontal DJs demonstrated good reliability (ICC > 0.789, TEMCV% < 10%).
• Contact time showed no significant relationship with vertical jump height or horizontal jump distance.
• A large correlation (r = 0.533) was found between the RSI of horizontal and vertical DJs, indicating a strong link in reactive ability.
• Contact times were significantly lower in vertical DJs compared to horizontal DJs (p < 0.0001).

Conclusions:

• Horizontal drop jumps are reliable assessment and training tools.
• Horizontal DJs may be more suitable for training reactive movements that do not necessitate extremely brief ground contact times.
• The findings suggest distinct applications for vertical and horizontal drop jumps in athletic training.