177
Views
4
CrossRef citations to date
0
Altmetric
Research Articles

The Effect of Load on Torques in Point-to-Point Arm Movements: A 3D Model

&
Pages 341-350 | Received 22 Sep 2011, Accepted 01 Jul 2012, Published online: 31 Aug 2012
 

ABSTRACT

A dynamic, 3-dimensional model was developed to simulate slightly restricted (pronation-supination was not allowed) point-to-point movements of the upper limb under different external loads, which were modeled using 3 objects of distinct masses held in the hand. The model considered structural and biomechanical properties of the arm and measured coordinates of joint positions. The model predicted muscle torques generated by muscles and needed to produce the measured rotations in the shoulder and elbow joints. The effect of different object masses on torque profiles, magnitudes, and directions were studied. Correlation analysis has shown that torque profiles in the shoulder and elbow joints are load invariant. The shape of the torque magnitude-time curve is load invariant but it is scaled with the mass of the load. Objects with larger masses are associated with a lower deflection of the elbow torque with respect to the sagittal plane. Torque direction–time curve is load invariant scaled with the mass of the load. The authors propose that the load invariance of the torque magnitude–time curve and torque direction–time curve holds for object transporting arm movements not restricted to a plane.

ACKNOWLEDGEMENT

This study has been supported by grant TAMOP-4.2.1, B-11/2/ KMR-2011-0002 from Pazmany Peter Catholic University and by a grant from the Hungarian Society for Sport Sciences. The authors would like to thank two anonymous reviewers and Dr. Gabor Fazekas for their valuable suggestions.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.