Reliability of the Reactive Strength Index and Time to Stabilization During Depth Jumps

• Published in: Journal of strength and conditioning research 2008-09, Vol.22 (5), p.1677-1682
• Main Authors: Flanagan, Eamonn P, Ebben, William P, Jensen, Randall L
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Athletes; Biomechanical Phenomena; Data collection; Exercise; Female; Humans; Isometric Contraction - physiology; Male; Muscle Fatigue - physiology; Muscle Strength - physiology; Physical Education and Training - methods; Physical Endurance; Reliability; Reproducibility of Results; Sample size; Studies; Time Factors; Track and Field - physiology; Variables; Young Adult
• ISSN: 1064-8011; 1533-4287
• DOI: 10.1519/JSC.0b013e318182034b

Flanagan, EP, Ebben, WP, and Jensen, RL. Reliability of the reactive strength index and time to stabilization during depth jumps. J Strength Cond Res 22(5)1677-1682, 2008-The reliability of the reactive strength index (RSI) and time to stabilization (TTS) during maximal-effort plyometric depth jumps was examined. Twenty-two subjects performed three depth jumps from a height of 30 cm. Measures such as height of jump (JH), ground-contact time (CT), RSI, and TTS were obtained and analyzed for reliability using Cronbach alpha reliability coefficient and intraclass correlations. The JH, CT, and RSI were shown to be highly reliable from trial to trial (evidenced by high Cronbach reliability coefficients (α > 0.95) and high single- and average-measures intraclass correlations (>0.9). Time to stabilization was not reliable from trial to trial, as evidenced by a low Cronbach reliability coefficient (α < 0.7) and poor single- (