shoulder joint forces and moments while using an IM system and (b) test the influence of gender and muscle loading type (concentric or eccentric) on kinetic and ...
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Concentric and eccentric shoulder rehabilitation biomechanics S S Kohles1,2,3*, K N Gregorczyk4, T C Phillips5, L T Brody5, J F Orwin5, and R Vanderby Jr5 1 Kohles Bioengineering, Portland, Oregon, USA 2 Department of Mechanical and Materials Engineering, Portland State University, Portland, Oregon, USA 3 Department of Surgery, Oregon Health and Science University, Portland, Oregon, USA 4 Soldier Systems Center, Department of the Army, Natick, Massachusetts, USA 5 Department of Orthopedics and Rehabilitation, University of Wisconsin, Madison, Wisconsin, USA The manuscript was received on 26 December 2005 and was accepted after revision for publication on 10 January 2007. DOI: 10.1243/09544119JEIM140
Abstract: The use of an impulse-momentum (IM) exercise technique was investigated for end-stage shoulder rehabilitation. The objectives of this study were to: (a) quantify the net shoulder joint forces and moments while using an IM system and (b) test the influence of gender and muscle loading type (concentric or eccentric) on kinetic and kinematic parameters. Fourteen healthy adults (eight males, six females) performed a repeated measures experiment on an instrumented device utilizing a cabled shuttle system. While maintaining 90° of shoulder abduction and 90° of elbow flexion, the subjects externally rotated their upper arm from 0° to 90° (concentric acceleration) and then internally rotated their upper arm back from 90° to the 0° position (eccentric deceleration). Shoulder joint forces and moments as well as rotational work and power were calculated using inverse dynamics (free-body forces and moments calculated at intersegmental joint centres). Overall concentric peak forces and moments were greater than eccentric peak forces and moments (P
