Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
Search
            ×
                        Mining
                        Mining
                            NIOSH
                            All CDC
                    Submit
                For a full list of topics:A-Z Index
                Advanced Search
            Advanced Search


The National Institute for Occupational Safety and Health (NIOSH)





Mining Publication: Torso Flexion Loads and Fatigue Failure Mode of Human Lumbosacral Motion Segments
Keywords: Data collection and recording Lifting or lowering Loading Rates Repetitive motions 
 Spinal cord
Original creation date: January 2005
Authors: S Gallagher, WS Marras, AS Litsky, D Burr
Peer Reviewed Journal Article - January 2005
Download PDF Document (0.29 MB)
NIOSHTIC2 Number: 20028583
Spine 2005 Oct; 30(20):2265-2273
Spine loads associated with lifting a 9-kg weight were estimated at three torso flexion angles (0, 22.5, and 45 deg), and lumbosacral motion segments were cyclically loaded using these loads until failure or to a maximum of 10,020 cycles. The objective was to simulate the postures and loads experienced by the lumbar spine during repetitive lifting of moderate weights in different torso flexion postures and to analyze the fatigue failure response of lumbosacral motion segments. Previous fatigue failure studies of lumbar motion segments have not reproduced the combination of spinal postures, loads, and load rates anticipated in different torso flexion postures during lifting tasks characteristic of those in occupational settings. Twelve fresh human lumbosacral spines were dissected into three motion segments each (L1-L2, L3-L4, and L5-S1). Motion segments within each spine were randomly assigned to a simulated torso flexion angle (0, 22.5, or 45 deg) using a partially balanced incomplete block experimental design. Spinal load and load rate were determined for each torso flexion angle using previously collected data from an EMG-assisted biomechanical model. Motion segments were creep loaded for 15 minutes, then cyclically loaded at 0.33 Hz. Fatigue life was taken as the number of cycles to failure (10-mm displacement after creep loading). Specimens were inspected to determine failure mechanisms. The degree of torso flexion had a dramatic impact on cycles to failure. Motion segments experiencing the 0-deg torso flexion condition averaged 8,253 cycles to failure (+/-2,895), while the 22.5-deg torso flexion angle averaged 3,257 (+/-4,443) cycles to failure, and motion segments at the 45-deg torso flexion angle lasted only 263 cycles (+/-646), on average. The difference was significant at P<0.0001, and torso flexion accounted for 50% of the total variance in cycles to failure. Fatigue failure of spinal tissues can occur rapidly when the torso is fully flexed during occupational lifting tasks; however, many thousands of cycles can be tolerated in a neutral posture. Future lifting recommendations should be sensitive to rapid development of fatigue failure in torso flexion.
Image of publication Torso Flexion Loads and Fatigue Failure Mode of Human Lumbosacral Motion SegmentsPeer Reviewed Journal Article - January 2005
Download PDF Document (0.29 MB)
NIOSHTIC2 Number: 20028583
Spine 2005 Oct; 30(20):2265-2273
See Also
The Availability of Primary Copper in Market Economy Countries: A Minerals Availability Appraisal
CFD Analysis of Mine Fire Smoke Spread and Reverse Flow Conditions
A Comparison of Fatigue Failure Responses of Old Versus Middle-Aged Lumbar Motion Segments in Simulated Flexed Lifting
Effects of Lifting in Four Restricted Postures
Effects of Posture on Dynamic Back Loading During a Cable Lifting Task
Electromagnetic Noise in Itmann Mine
Methane Emission Rate Studies in a Northern West Virginia Mine
Seismic Event Data Acquisition and Processing: Distribution and Coordination Across PC-Based Networks
Task Analysis
Technology News 521 - Development of a Mobile Manipulator to Reduce Lifting Accidents
Page last reviewed: September 21, 2012
Page last updated: September 21, 2012
Content source: National Institute for Occupational Safety and Health, Mining Program
Facebook
        Twitter
        LinkedIn
        Syndicate Mining
        Site BrowserSafety and Health TopicsData & StatisticsMethodologyMine DisastersMSHA Data FilesMine & Mineworker ChartsTools & PublicationsTools You Can UsePublicationsNews & ArticlesResearch ProgramNORA Mining CouncilStrategic PlanMining Program, 2019-2023Miner Health Program, 2020-2030ProjectsContractsFunding OpportunitiesMining LinksAbout UsContact NIOSH MiningEmploymentFacilitiesHistoryVisitor Information NIOSH Homepage
 NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification / Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
				Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
				You will be subject to the destination website's privacy policy when you follow the link.
				CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue