Authors: Frost, David¹; Cronin, John²; Newton, Robert²

Source: Sports Biomechanics, Volume 7, Number 3, September 2008 , pp. 372-385(14)

Publisher: Routledge, part of the Taylor & Francis Group

Abstract:

Explosive upper-body movements, with which the load is not thrown (non-ballistic), may comprise a phase during which forces are produced in opposition to the motion of the load. Thirty men completed three test sessions (free weight, ballistic, and pneumatic), each consisting of a one-repetition maximum (1-RM) and four explosive repetitions of a bench press at six loads (15, 30, 45, 60, 75, and 90% 1-RM). The end of the lifting phase for the non-ballistic conditions (free weight and pneumatic) was defined by: the point of peak barbell displacement and the point at which the vertical force became negative (positive work). When analysed by peak displacement, the ballistic condition elicited significantly greater mean velocity, force, and power at loads of 15-60% 1-RM compared with the free weight condition. When the period of negative work was removed, the mean free weight velocity, force, and power at loads below 60% 1-RM increased. Consequently, the only differences between the free weight and ballistic conditions were found at loads of 15% and 30% 1-RM. Including a period of negative work may underestimate all kinematic and kinetic variables dependent on the time to, or position of, the end of the lifting phase, for non-ballistic efforts.

Keywords: Ballistic; kinematics; kinetics; upper body; work

Document Type: Research article

DOI: http://dx.doi.org/10.1080/14763140802273005

Affiliations: 1: School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia,Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada 2: School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia

Publication date: 2008-09-01

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