Relationship Between Reactive Strength Variables in Horizontal and Vertical Drop Jumps

• Published in: Journal of strength and conditioning research Vol. 26; no. 5; pp. 1407 - 1412
• Main Authors: Ball, Nick B., Zanetti, Sara
• Format: Journal Article
• Language: English
• Published: United States National Strength and Conditioning Association 01-05-2012; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Adult; Correlation analysis; Female; Humans; Leg - physiology; Male; Measurement errors; Movement; Muscle Strength; Muscle, Skeletal - physiology; Plyometric Exercise; Random Allocation; Sports training; Studies; Task Performance and Analysis; Time Factors; Young Adult
• ISSN: 1064-8011; 1533-4287
• DOI: 10.1519/JSC.0b013e3182510870

ABSTRACTBall, NB, and Zanetti, S. Relationship between reactive strength variables in horizontal and vertical drop jumps. J Strength Cond Res 26(5)1407–1412, 2012—The aim of this study was to investigate the relationship between reactive strength in a vertical and a horizontal drop jump (DJ). Subjects (n = 28) with previous jump training experience, performed 6 vertical DJs and 6 horizontal DJs from a 0.4-m box. Contact time, height jumped, distance jumped, and reactive strength index (RSI) were calculated and analyzed. Typical error measurements (TEMCV%) and intraclass correlations (ICCs) were used to assess the intrasubject reliability. Relationships between jumps and within jumps of the aforementioned variables were assessed using ICCs. The ICC (r > 0.789) and the TEMCV% (<10%) indicated good reliability for both vertical and horizontal DJs across each variable. Contact time showed no relationship between jumps (r = 0.222) and had no effect on the vertical DJ height (r = 0.152) or horizontal DJ distance (r = 0.261). The RSI correlation (r = 0.533) indicated a large relationship between reactive ability in the horizontal DJ and the vertical DJ. Contact times were significantly lower in vertical DJs compared with horizontal DJs (p < 0.0001). This study indicated that horizontal DJs are reliable and may be better used to train reactive movements that do not require brief contact times.