Title: The influence of head-neck position on wrist flexor strength

Authors: Sanjib Kumar Das; Siddhartha Sen; Suman Mukhopadhyay

Addresses: Ergonomics and Human Factors Engineering, National Institute of Industrial Engineering, Mumbai-400087, India ' Department of Physiotherapy, S.B.S. Post Graduate Institute of Biomedical and Research, Dehradun, India ' Ergonomics and Human Factors Engineering, National Institute of Industrial Engineering, Mumbai-400087, India

Abstract: Evaluation of muscle strength is important for human factors engineers, ergonomists, and healthcare practitioners to formulate successful ergonomic interventions, prescribe exercise regimens, and model credible rehabilitation programmes. Although previous studies have identified the influence of different head-neck (H-N) positions on joint strength production, none have assessed the influence of H-N position on wrist strength. The objective of this study was to compare wrist flexor strength in different head-neck (H-N) positions, including a neutral neck position and eight non-neutral positions involving single or combined rotations in the sagittal and horizontal planes. Isometric flexor strength of the left wrist was measured from 30 right-handed healthy female volunteers, using an isokinetic dynamometer, in each of the nine H-N positions in a random order. Among the nine H-N positions, significant differences in wrist flexor strength were observed only between neck rotation to the right and the remaining positions. These results suggest that H-N positions should be considered while assessing or predicting wrist strength. And, more generally, the results support that strength at a given joint can in some cases is substantially influenced by the postures of others joints, even those rather separated from the joint in question.

Keywords: isometric flexor strength; isokinetic dynamometer; wrist flexor torque; asymmetric tonic neck reflex; head-neck position; wrist flexor strength; muscle strength; human factors; ergonomics; wrist strength; females; neck rotation; joint posture.

DOI: 10.1504/IJHFMS.2015.068123

International Journal of Human Factors Modelling and Simulation, 2015 Vol.5 No.1, pp.53 - 60

Received: 16 Nov 2013
Accepted: 04 Dec 2014

Published online: 18 Mar 2015 *

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