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Relationships Between Rapid Isometric Torque Characteristics and Vertical Jump Performance in Division I Collegiate American Football Players: Influence of Body Mass Normalization

Thompson, Brennan J.1; Ryan, Eric D.2; Sobolewski, Eric J.2; Smith, Doug B.1; Akehi, Kazuma1; Conchola, Eric C.1; Buckminster, Tyler3

Journal of Strength & Conditioning Research: October 2013 - Volume 27 - Issue 10 - p 2737–2742
doi: 10.1519/JSC.0b013e318281637b
Original Research

Abstract: Thompson, BJ, Ryan, ED, Sobolewski, EJ, Smith, DB, Akehi, K, Conchola, EC, and Buckminster, T. Relationships between rapid isometric torque characteristics and vertical jump performance in division I collegiate American football players: Influence of body mass normalization. J Strength Cond Res 27(10): 2737–2742, 2013—The purpose of the present study was to examine the relationships between absolute and body mass–normalized rapid isometric torque variables and vertical jump (VJ) performance of the leg extensors and flexors in elite National Collegiate Athletic Association Division I Football Bowl Subdivision collegiate American football players. Thirty-one players performed isometric maximal voluntary contractions of the leg extensor and flexor muscle groups and a countermovement VJ. Rate of torque development (RTD) and the contractile impulse (IMPULSE) were determined from 0 to 30, 0 to 50, 0 to 100, and 0 to 200 milliseconds from the onset of muscular contraction. The relationships between absolute and normalized rapid torque variables and VJ performance were assessed using correlation coefficients (r). There were no significant correlations (p > 0.05) observed between the absolute rapid torque variables and VJ performance, except for leg flexion RTD at 0–200 milliseconds (p = 0.024). All normalized rapid torque variables of the leg extensors and flexors were significantly correlated to VJ performance (p ≤ 0.001–0.026). These findings indicated that normalizing rapid torque variables to body mass improves the relationships between isometric rapid torque variables and VJ performance and normalized leg extension and flexion are both similarly related to VJ performance. Strength and conditioning professionals may use these findings in an attempt to identify and monitor dynamic sport performance. Furthermore, future studies examining the relationship between dynamic on the field performances and laboratory-based isometric strength testing may consider including normalized rapid torque variables.

1Applied Musculoskeletal and Human Physiology Laboratory, Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma

2Neuromuscular Research Laboratory, Department of Exercise and Sport Science, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina

3Department of Athletics, Oklahoma State University, Stillwater, Oklahoma

Address correspondence to Dr. Eric D. Ryan,

Copyright © 2013 by the National Strength & Conditioning Association.