Author: Desmoulin G.T. and Rabinoff M.
Publication: Int. J. Forensic Engineering, Vol. 2, No. 4, 2015.
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.