Title: Biomechanical assessment of the connection between risk of wrist fracture and the dumbbell chest press exercise performed on an exercise ball

Authors: Geoffrey Thor Desmoulin; Marc A. Rabinoff

Addresses: GTD Engineering Inc., 218-E4th Ave, Vancouver, V5T-1G5, Canada ' Rabinoff Consulting Services, Inc., 7600 West Coal Mine Ave. Unit A, Littleton, CO 80123, USA

Abstract: Multiple incidents of exercise balls bursting during a dumbbell chest press have been reported. This study quantified the dynamics of the dumbbell chest press performed on such balls and the force applied throughout the exercise cycle. To do so, a well-documented case was replicated using subjects of similar weight, background and athletic ability in the same dumbbell chest press motion. Subjects were instructed to perform repetitions on the exercise balls at both a self-selected pace and at maximal speed using various masses. Dynamic measurements were made to record ball loading, ball loading rate, ball compression, and kinematics of the subjects. Peak loads averaged 2084 N in the case of fast trials and 1815 N for self-selected speed trials. Biomechanical aspects of injury causation and the safe use of exercise balls are discussed throughout the products life cycle; from design and manufacturing to the conditioning professional and athlete end user.

Keywords: exercise balls; physio balls; Swiss balls; wrist fracture; Galeazzi; equipment failure; dumbbell press; dumbbell chest press; forensic engineering; biomechanical assessment; fracture risks; biomechanics; ball bursting; dumbbells; ball loading rate; ball compression; kinematics; peak loads; exercise cycle; exercise injuries; injury causation; safe use; exercise ball safety; product life cycle.

DOI: 10.1504/IJFE.2015.075262

International Journal of Forensic Engineering, 2015 Vol.2 No.4, pp.253 - 264

Received: 16 Oct 2014
Accepted: 11 Jan 2015
Published online: 09 Mar 2016 *

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