Inter-individual variation in vertebral kinematics affects predictions of neck musculoskeletal models

Derek D Nevins; Liying Zheng; Anita N Vasavada

doi:10.1016/j.jbiomech.2014.08.017

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Inter-individual variation in vertebral kinematics affects predictions of neck musculoskeletal models

Journal article

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Peer reviewed

Inter-individual variation in vertebral kinematics affects predictions of neck musculoskeletal models

Derek D Nevins, Liying Zheng and Anita N Vasavada

Journal of biomechanics, Vol.47(13), pp.3288-3294

10/17/2014

DOI: https://doi.org/10.1016/j.jbiomech.2014.08.017

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https://hdl.handle.net/2376/116657

PMCID: PMC4203672

PMID: 25234351

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https://doi.org/10.1016/j.jbiomech.2014.08.017View

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Abstract

Cervical spine kinematics

Neck strength

Neck models

Ergonomics

Experimental studies have found significant variation in cervical intervertebral kinematics (IVK) among healthy subjects, but the effect of this variation on biomechanical properties, such as neck strength, has not been explored. The goal of this study was to quantify variation in model predictions of extension strength, flexion strength and gravitational demand (the ratio of gravitational load from the weight of the head to neck muscle extension strength), due to inter-subject variation in IVK. IVK were measured from sagittal radiographs of 24 subjects (14F, 10M) in five postures: maximal extension, mid-extension, neutral, mid-flexion, and maximal flexion. IVK were defined by the position (anterior-posterior and superior-inferior) of each cervical vertebra with respect to T1 and its angle with respect to horizontal, and fit with a cubic polynomial over the range of motion. The IVK of each subject were scaled and incorporated into musculoskeletal models to create models that were identical in muscle force- and moment-generating properties but had subject-specific kinematics. The effect of inter-subject variation in IVK was quantified using the coefficient of variation (COV), the ratio of the standard deviation to the mean. COV of extension strength ranged from 8% to 15% over the range of motion, but COV of flexion strength was 20–80%. Moreover, the COV of gravitational demand was 80–90%, because the gravitational demand is affected by head position as well as neck strength. These results indicate that including inter-individual variation in models is important for evaluating neck musculoskeletal biomechanical properties.

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Title: Inter-individual variation in vertebral kinematics affects predictions of neck musculoskeletal models
Creators: Derek D Nevins - Washington State University, Pullman, WA, USA
Liying Zheng - University of Pittsburgh, Pittsburgh, PA, USA
Anita N Vasavada - Washington State University, Pullman, WA, USA
Publication Details: Journal of biomechanics, Vol.47(13), pp.3288-3294
Academic Unit: Chemical Engineering and Bioengineering, School of
Publisher: Elsevier Ltd
Identifiers: 99900547641701842
Language: English
Resource Type: Journal article