Alterations in trunk bending stiffness following changes in stability and equilibrium demands of a load holding task

Iman Shojaei, Cazmon Suri, Jaap H. van Dieën, Babak Bazrgari

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The contribution of the trunk neuromuscular system (TNS) to spine stability has been shown in earlier studies by characterizing changes in antagonistic activity of trunk muscles following alterations in stability demands of a task. Whether and/or how much such changes in the response of TNS to alteration in stability demand of the task alter spinal stiffness remains unclear. To address this research gap, a repeated measure study was conducted on twenty gender-balanced asymptomatic individuals to evaluate changes in trunk bending stiffness throughout the lumbar spine's range of flexion following alterations in both stability and equilibrium demands of a load holding task. Trunk bending stiffness was determined using trunk stiffness tests in upright posture on a rigid metal frame under different equilibrium and stability demands on the lower back. Increasing the stability demand by increasing the height of lifted load ∼30 cm only increased trunk bending stiffness (∼39%) over the lower range of lumbar flexion and under the low equilibrium demand condition. Similarly, increasing the equilibrium demand of the task by increasing the weight of lifted load by 3.5 kg only increased trunk bending stiffness (55%) over the low range of lumbar flexion and under the low stability demand condition. Our results suggest a non-linear relationship between changes in stability and equilibrium demands of a task and the contribution of TNS to trunk bending stiffness. Specifically, alterations in TNS response to changes in stability and equilibrium demand of a given task will increase stiffness of the trunk only if the background stiffness is low.

Original languageEnglish
Pages (from-to)163-170
Number of pages8
JournalJournal of Biomechanics
Volume77
Early online date20 Jul 2018
DOIs
Publication statusPublished - 22 Aug 2018

Fingerprint

Spine
Stiffness
Posture
Metals
Weights and Measures
Muscles
Loads (forces)
Research
Bending (deformation)
Muscle

Keywords

  • Spinal stability
  • Stability and equilibrium demands of a physical task
  • Trunk bending stiffness
  • Trunk muscle activity

Cite this

@article{b9f5b2d2af7643acbd20e3d435291d2b,
title = "Alterations in trunk bending stiffness following changes in stability and equilibrium demands of a load holding task",
abstract = "The contribution of the trunk neuromuscular system (TNS) to spine stability has been shown in earlier studies by characterizing changes in antagonistic activity of trunk muscles following alterations in stability demands of a task. Whether and/or how much such changes in the response of TNS to alteration in stability demand of the task alter spinal stiffness remains unclear. To address this research gap, a repeated measure study was conducted on twenty gender-balanced asymptomatic individuals to evaluate changes in trunk bending stiffness throughout the lumbar spine's range of flexion following alterations in both stability and equilibrium demands of a load holding task. Trunk bending stiffness was determined using trunk stiffness tests in upright posture on a rigid metal frame under different equilibrium and stability demands on the lower back. Increasing the stability demand by increasing the height of lifted load ∼30 cm only increased trunk bending stiffness (∼39{\%}) over the lower range of lumbar flexion and under the low equilibrium demand condition. Similarly, increasing the equilibrium demand of the task by increasing the weight of lifted load by 3.5 kg only increased trunk bending stiffness (55{\%}) over the low range of lumbar flexion and under the low stability demand condition. Our results suggest a non-linear relationship between changes in stability and equilibrium demands of a task and the contribution of TNS to trunk bending stiffness. Specifically, alterations in TNS response to changes in stability and equilibrium demand of a given task will increase stiffness of the trunk only if the background stiffness is low.",
keywords = "Spinal stability, Stability and equilibrium demands of a physical task, Trunk bending stiffness, Trunk muscle activity",
author = "Iman Shojaei and Cazmon Suri and {van Die{\"e}n}, {Jaap H.} and Babak Bazrgari",
year = "2018",
month = "8",
day = "22",
doi = "10.1016/j.jbiomech.2018.07.005",
language = "English",
volume = "77",
pages = "163--170",
journal = "Journal of Biomechanics",
issn = "0021-9290",
publisher = "Elsevier Limited",

}

Alterations in trunk bending stiffness following changes in stability and equilibrium demands of a load holding task. / Shojaei, Iman; Suri, Cazmon; van Dieën, Jaap H.; Bazrgari, Babak.

In: Journal of Biomechanics, Vol. 77, 22.08.2018, p. 163-170.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Alterations in trunk bending stiffness following changes in stability and equilibrium demands of a load holding task

AU - Shojaei, Iman

AU - Suri, Cazmon

AU - van Dieën, Jaap H.

AU - Bazrgari, Babak

PY - 2018/8/22

Y1 - 2018/8/22

N2 - The contribution of the trunk neuromuscular system (TNS) to spine stability has been shown in earlier studies by characterizing changes in antagonistic activity of trunk muscles following alterations in stability demands of a task. Whether and/or how much such changes in the response of TNS to alteration in stability demand of the task alter spinal stiffness remains unclear. To address this research gap, a repeated measure study was conducted on twenty gender-balanced asymptomatic individuals to evaluate changes in trunk bending stiffness throughout the lumbar spine's range of flexion following alterations in both stability and equilibrium demands of a load holding task. Trunk bending stiffness was determined using trunk stiffness tests in upright posture on a rigid metal frame under different equilibrium and stability demands on the lower back. Increasing the stability demand by increasing the height of lifted load ∼30 cm only increased trunk bending stiffness (∼39%) over the lower range of lumbar flexion and under the low equilibrium demand condition. Similarly, increasing the equilibrium demand of the task by increasing the weight of lifted load by 3.5 kg only increased trunk bending stiffness (55%) over the low range of lumbar flexion and under the low stability demand condition. Our results suggest a non-linear relationship between changes in stability and equilibrium demands of a task and the contribution of TNS to trunk bending stiffness. Specifically, alterations in TNS response to changes in stability and equilibrium demand of a given task will increase stiffness of the trunk only if the background stiffness is low.

AB - The contribution of the trunk neuromuscular system (TNS) to spine stability has been shown in earlier studies by characterizing changes in antagonistic activity of trunk muscles following alterations in stability demands of a task. Whether and/or how much such changes in the response of TNS to alteration in stability demand of the task alter spinal stiffness remains unclear. To address this research gap, a repeated measure study was conducted on twenty gender-balanced asymptomatic individuals to evaluate changes in trunk bending stiffness throughout the lumbar spine's range of flexion following alterations in both stability and equilibrium demands of a load holding task. Trunk bending stiffness was determined using trunk stiffness tests in upright posture on a rigid metal frame under different equilibrium and stability demands on the lower back. Increasing the stability demand by increasing the height of lifted load ∼30 cm only increased trunk bending stiffness (∼39%) over the lower range of lumbar flexion and under the low equilibrium demand condition. Similarly, increasing the equilibrium demand of the task by increasing the weight of lifted load by 3.5 kg only increased trunk bending stiffness (55%) over the low range of lumbar flexion and under the low stability demand condition. Our results suggest a non-linear relationship between changes in stability and equilibrium demands of a task and the contribution of TNS to trunk bending stiffness. Specifically, alterations in TNS response to changes in stability and equilibrium demand of a given task will increase stiffness of the trunk only if the background stiffness is low.

KW - Spinal stability

KW - Stability and equilibrium demands of a physical task

KW - Trunk bending stiffness

KW - Trunk muscle activity

UR - http://www.scopus.com/inward/record.url?scp=85050147304&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85050147304&partnerID=8YFLogxK

U2 - 10.1016/j.jbiomech.2018.07.005

DO - 10.1016/j.jbiomech.2018.07.005

M3 - Article

VL - 77

SP - 163

EP - 170

JO - Journal of Biomechanics

JF - Journal of Biomechanics

SN - 0021-9290

ER -