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Jain A, Kandwal P, Sethy SS, Verma A. Letter to the Editor Regarding "Hooks Versus Pedicle Screws at the Upper Instrumented Level". Spine (Phila Pa 1976) 2024; 49:E133. [PMID: 37621224 DOI: 10.1097/brs.0000000000004809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023]
Affiliation(s)
- Akash Jain
- Department of Orthopaedics, All India Institute of Medical Sciences, Rishikesh, India
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Kazemi Z, Arjmand N, Mazloumi A, Karimi Z, Keihani A, Ghasemi MS. Effect of muscular fatigue on the cumulative lumbar damage during repetitive lifting task: a comparative study of damage calculation methods. ERGONOMICS 2024; 67:566-581. [PMID: 37418312 DOI: 10.1080/00140139.2023.2234678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/02/2023] [Indexed: 07/09/2023]
Abstract
Several methods have been put forward to quantify cumulative loads; however, limited evidence exists as to the subsequent damages and the role of muscular fatigue. The present study assessed whether muscular fatigue could affect cumulative damage imposed on the L5-S1 joint. Trunk muscle electromyographic (EMG) activities and kinematics/kinetics of 18 healthy male individuals were evaluated during a simulated repetitive lifting task. A traditional EMG-assisted model of the lumbar spine was modified to account for the effect of erector spinae fatigue. L5-S1 compressive loads for each lifting cycle were estimated based on varying (i.e. actual), fatigue-modified, and constant Gain factors. The corresponding damages were integrated to calculate the cumulative damage. Moreover, the damage calculated for one lifting cycle was multiplied by the lifting frequency, as the traditional approach. Compressive loads and the damages obtained through the fatigue-modified model were predicted in close agreement with the actual values. Similarly, the difference between actual damages and those driven by the traditional approach was not statistically significant (p = 0.219). However, damages based on a constant Gain factor were significantly greater than those based on the actual (p = 0.012), fatigue-modified (p = 0.017), and traditional (p = 0.007) approaches.Practitioner summary: In this study, we managed to include the effect of muscular fatigue on cumulative lumbar damage calculations. Including the effect of muscular fatigue leads to an accurate estimation of cumulative damages while eliminating computational complexity. However, using the traditional approach also appears to provide acceptable estimates for ergonomic assessments.
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Affiliation(s)
- Zeinab Kazemi
- Department of Industrial Engineering, Clemson University, Clemson, SC, USA
| | - Navid Arjmand
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Adel Mazloumi
- Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Sports Medicine Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Zanyar Karimi
- Department of Ergonomics, School of Public Health, Urmia University of Medical Sciences, Tehran, Iran
| | - Ahmadreza Keihani
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Gallagher S, Barbe MF. The impaired healing hypothesis: a mechanism by which psychosocial stress and personal characteristics increase MSD risk? ERGONOMICS 2022; 65:573-586. [PMID: 34463204 PMCID: PMC9847256 DOI: 10.1080/00140139.2021.1974103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/23/2021] [Indexed: 05/09/2023]
Abstract
While the effects of physical risk factors on MSD development have been a primary focus of musculoskeletal research, psychological stressors, and certain personal characteristics (e.g. ageing, sex, and obesity) are also associated with increased MSD risk. The psychological and personal characteristics listed above share a common characteristic: all are associated with disruption of the body's neuroendocrine and immune responses resulting in an impaired healing process. An impaired healing response may result in reduced fatigue life of musculoskeletal tissues due to a diminished ability to keep pace with accumulating damage (perhaps reparable under normal circumstances), and an increased vulnerability of damaged tissue to further trauma owing to the prolonged healing process. Research in engineered self-healing materials suggests that decreased healing kinetics in the presence of mechanical loading can substantially reduce the fatigue life of materials. A model of factors influencing damage accrual and healing will be presented. Practitioner summary: This article provides a potential reason why musculoskeletal disorder risk is affected by psychosocial stress, age, sex, and obesity. The reason is that these factors are all associated with a slower than normal healing response. This may lead to faster damage development in musculoskeletal tissues resulting in higher MSD risk.
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Affiliation(s)
- Sean Gallagher
- Industrial and Systems Engineering Department, Auburn University, Auburn, AL, USA
| | - Mary F Barbe
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
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Costi JJ, Ledet EH, O'Connell GD. Spine biomechanical testing methodologies: The controversy of consensus vs scientific evidence. JOR Spine 2021; 4:e1138. [PMID: 33778410 PMCID: PMC7984003 DOI: 10.1002/jsp2.1138] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022] Open
Abstract
Biomechanical testing methodologies for the spine have developed over the past 50 years. During that time, there have been several paradigm shifts with respect to techniques. These techniques evolved by incorporating state-of-the-art engineering principles, in vivo measurements, anatomical structure-function relationships, and the scientific method. Multiple parametric studies have focused on the effects that the experimental technique has on outcomes. As a result, testing methodologies have evolved, but there are no standard testing protocols, which makes the comparison of findings between experiments difficult and conclusions about in vivo performance challenging. In 2019, the international spine research community was surveyed to determine the consensus on spine biomechanical testing and if the consensus opinion was consistent with the scientific evidence. More than 80 responses to the survey were received. The findings of this survey confirmed that while some methods have been commonly adopted, not all are consistent with the scientific evidence. This review summarizes the scientific literature, the current consensus, and the authors' recommendations on best practices based on the compendium of available evidence.
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Affiliation(s)
- John J. Costi
- Biomechanics and Implants Research Group, Medical Device Research Institute, College of Science and EngineeringFlinders UniversityAdelaideAustralia
| | - Eric H. Ledet
- Department of Biomedical EngineeringRensselaer Polytechnic InstituteTroyNew YorkUSA
- Research and Development ServiceStratton VA Medical CenterAlbanyNew YorkUSA
| | - Grace D. O'Connell
- Department of Mechanical EngineeringUniversity of California‐BerkeleyBerkeleyCaliforniaUSA
- Department of Orthopaedic SurgeryUniversity of California‐San FranciscoSan FranciscoCaliforniaUSA
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Abstract
Causal pathways between training loads and the mechanisms of tissue damage and athletic injury are poorly understood. Here, the relation between specific training load measures and metrics, and causal pathways of gradual onset and traumatic injury are examined. Currently, a wide variety of internal and external training load measures and metrics exist, with many of these being commonly utilized to evaluate injury risk. These measures and metrics can conceptually be related to athletic injury through the mechanical load-response pathway, the psycho-physiological load-response pathway, or both. However, the contributions of these pathways to injury vary. Importantly, tissue fatigue damage and trauma through the mechanical load-response pathway is poorly understood. Furthermore, considerable challenges in quantifying this pathway exist within applied settings, evidenced by a notable absence of validation between current training load measures and tissue-level mechanical loads. Within this context, the accurate quantification of mechanical loads holds considerable importance for the estimation of tissue damage and the development of more thorough understandings of injury risk. Despite internal load measures of psycho-physiological load speculatively being conceptually linked to athletic injury through training intensity and the effects of psycho-physiological fatigue, these measures are likely too far removed from injury causation to provide meaningful, reliable relationships with injury. Finally, we used a common training load metric as a case study to show how the absence of a sound conceptual rationale and spurious links to causal mechanisms can disclose the weaknesses of candidate measures as tools for altering the likelihood of injuries, aiding the future development of more refined injury risk assessment methods.
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Gallagher S, Schall MC, Sesek RF, Huangfu R. An Upper Extremity Risk Assessment Tool Based on Material Fatigue Failure Theory: The Distal Upper Extremity Tool (DUET). HUMAN FACTORS 2018; 60:1146-1162. [PMID: 30063405 DOI: 10.1177/0018720818789319] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE Musculoskeletal tissues repeatedly loaded in vitro fail in accordance with material fatigue failure theory, and there is evidence to suggest that the same process occurs in vivo. The current paper presents a new upper extremity risk assessment tool, the Distal Upper Extremity Tool (DUET), predicated on material fatigue failure theory. METHODS DUET requires an estimate of force exertion level and the number of repetitions performed to derive estimates of damage and probabilities of experiencing a distal upper extremity outcome. Damage accrued over multiple tasks may be summed to estimate the cumulative damage (CD) accrued over a workday. Validation of this tool was performed using five distal upper extremity (DUE) outcomes (involving medical visits and pain) from an existing epidemiological database involving data from six automotive manufacturing plants. Logistic regression was used to assess the association of the log of the DUET CD measure to DUE outcomes. RESULTS Results demonstrated that the log of the DUET CD measure was highly associated with all five DUE outcomes in both crude analyses and those adjusted for site, age, gender, and body mass index ( p < .01). A model relating the continuous DUET log CD score to the probability of the DUE outcome Injury + Pain Last Year was developed, which demonstrated a significant dose-response relationship. CONCLUSIONS Results suggest that fatigue failure-based risk assessment techniques are highly associated with DUE outcomes and provide support for the notion that an underlying fatigue failure process may be involved in the development of upper extremity musculoskeletal disorders.
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Gale NC, Zeigler SL, Towler C, Mondal S, Issen KA, Mesfin A, Michalek AJ, Kuxhaus L. Increased lumbar spinal column laxity due to low-angle, low-load cyclic flexion may predispose to acute injury. JOR Spine 2018; 1:e1038. [PMID: 31463453 PMCID: PMC6686791 DOI: 10.1002/jsp2.1038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 09/10/2018] [Accepted: 10/29/2018] [Indexed: 11/05/2022] Open
Abstract
Lumbar spinal column laxity contributes to instability, increasing the risk of low back injury and pain. Until the laxity increase due to the cyclic loads of daily living can be quantified, the associated injury risk cannot be predicted clinically. This work cyclically loaded 5-vertebra lumbar motion segments (7 skeletally-mature cervine specimens, 5 osteoporotic human cadaver specimens) for 20 000 cycles of low-load low-angle (15°) flexion. The normalized neutral zone lengths and slopes of the load-displacement hysteresis loops showed a similar increase in spinal column laxity across species. The intervertebral kinematics also changes with cyclic loading. Differences in the location and magnitude of surface strain on the vertebral bodies (0.34% ± 0.11% in the cervine specimens, and 3.13% ± 1.69% in the human cadaver specimens) are consistent with expected fracture modes in these populations. Together, these results provide biomechanical evidence of spinal column damage during high-cycle low-load low-angle loading.
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Affiliation(s)
- Nicole C. Gale
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew York
| | | | | | - Sumona Mondal
- Department of MathematicsClarkson UniversityPotsdamNew York
| | - Kathleen A. Issen
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew York
| | - Addisu Mesfin
- Departments of Orthopaedic Surgery and NeurosurgeryUniversity of RochesterRochesterNew York
| | - Arthur J. Michalek
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew York
| | - Laurel Kuxhaus
- Department of Mechanical and Aeronautical EngineeringClarkson UniversityPotsdamNew York
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Gallagher S, Sesek RF, Schall MC, Huangfu R. Development and validation of an easy-to-use risk assessment tool for cumulative low back loading: The Lifting Fatigue Failure Tool (LiFFT). APPLIED ERGONOMICS 2017; 63:142-150. [PMID: 28477843 DOI: 10.1016/j.apergo.2017.04.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 06/07/2023]
Abstract
Recent evidence suggests that musculoskeletal disorders (MSDs) may be the result of a fatigue failure process in affected tissues. This paper describes a new low back exposure assessment tool (the Lifting Fatigue Failure Tool [LiFFT]), which estimates a "daily dose" of cumulative loading on the low back using fatigue failure principles. Only three variables are necessary to derive the cumulative load associated with a lifting task: the weight of the load, the maximum horizontal distance from the spine to the load, and the number of repetitions for tasks performed during the workday. The new tool was validated using two existing epidemiological databases: the Lumbar Motion Monitor (LMM) database, and a database from a U.S. automotive manufacturer. The LiFFT cumulative damage metric explained 92% of the deviance in low back disorders (LBDs) in the LMM database and 72-95% of the deviance in low back outcomes in the automotive database (depending on the outcome measure). Thus, LiFFT is practitioner friendly and its cumulative damage metric highly related to low back outcomes.
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Affiliation(s)
- Sean Gallagher
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL, USA.
| | - Richard F Sesek
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL, USA
| | - Mark C Schall
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL, USA
| | - Rong Huangfu
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL, USA
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Gallagher S, Schall MC. Musculoskeletal disorders as a fatigue failure process: evidence, implications and research needs. ERGONOMICS 2017; 60:255-269. [PMID: 27376409 DOI: 10.1080/00140139.2016.1208848] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Mounting evidence suggests that musculoskeletal disorders (MSDs) may be the result of a fatigue failure process in musculoskeletal tissues. Evaluations of MSD risk in epidemiological studies and current MSD risk assessment tools, however, have not yet incorporated important principles of fatigue failure analysis in their appraisals of MSD risk. This article examines the evidence suggesting that fatigue failure may play an important role in the aetiology of MSDs, assesses important implications with respect to MSD risk assessment and discusses research needs that may be required to advance the scientific community's ability to more effectively prevent the development of MSDs. Practitioner Summary: Evidence suggests that musculoskeletal disorders (MSDs) may result from a fatigue failure process. This article proposes a unifying framework that aims to explain why exposure to physical risk factors contributes to the development of work-related MSDs. Implications of that framework are discussed.
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Affiliation(s)
- Sean Gallagher
- a Industrial and Systems Engineering , Auburn University , Auburn , AL , USA
| | - Mark C Schall
- a Industrial and Systems Engineering , Auburn University , Auburn , AL , USA
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Abstract
STUDY DESIGN Microstructural investigation of vibration-induced disruption of the flexed lumbar disc. OBJECTIVE The aim of the study was to explore micro-level structural damage in motion segments subjected to vibration at subcritical peak loads. SUMMARY OF BACKGROUND DATA Epidemiological evidence suggests that cumulative whole body vibration may damage the disc and thus play an important role in low back pain. In vitro investigations have produced herniations via cyclic loading (and cyclic with added vibrations as an exacerbating exposure), but offered only limited microstructural analysis. METHODS Twenty-nine healthy mature ovine lumbar motion segments flexed 7° and subjected to vibration loading (1300 ± 500 N) in a sinusoidal waveform at 5 Hz to simulate moderately severe physiologic exposure. Discs were tested either in the range of 20,000 to 48,000 cycles (medium dose) or 70,000 to 120,000 cycles (high dose). Damaged discs were analyzed microstructurally. RESULTS There was no large drop in displacement over the duration of both vibration doses indicating an absence of catastrophic failure in all tests. The tested discs experienced internal damage that included delamination and disruption to the inner and mid-annular layers as well as diffuse tracking of nucleus material, and involved both the posterior and anterior regions. Less frequent tearing between the inner disc and endplate was also observed. Annular distortions also progressed into a more severe form of damage, which included intralamellar tearing and buckling and obvious strain distortion around the bridging elements within the annular wall. CONCLUSION Vibration loading causes delamination and disruption of the inner and mid-annular layers and limited diffuse tracking of nucleus material. These subtle levels of disruption could play a significant role in initiating the degenerative cascade via micro-level disruption leading to cell death and altered nutrient pathways. LEVEL OF EVIDENCE 5.
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Tang R, Gungor C, Sesek RF, Foreman KB, Gallagher S, Davis GA. Morphometry of the lower lumbar intervertebral discs and endplates: comparative analyses of new MRI data with previous findings. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2016; 25:4116-4131. [DOI: 10.1007/s00586-016-4405-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Revised: 01/11/2016] [Accepted: 01/15/2016] [Indexed: 11/24/2022]
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Abstract
Vertebral fractures are one of the most common fractures associated with skeletal fragility and can cause as much morbidity as hip fractures. However, the epidemiology of vertebral fractures differs from that of osteoporotic fractures at other skeletal sites in important ways, largely because only one quarter to one-third of vertebral fractures are recognized clinically at the time of their occurrence and otherwise require lateral spine imaging to be recognized. This article first reviews the prevalence and incidence of clinical and radiographic vertebral fractures in populations across the globe and secular trends in the incidence of vertebral fracture over time. Next, associations of vertebral fractures with measures of bone mineral density and bone microarchitecture are reviewed followed by associations of vertebral fracture with various textural measures of trabecular bone, including trabecular bone score. Finally, the article reviews clinical risk factors for vertebral fracture and the association of vertebral fractures with morbidity, mortality, and other subsequent adverse health outcomes.
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Affiliation(s)
- John T Schousboe
- Park Nicollet Osteoporosis Center, Park Nicollet Clinic, HealthPartners, Minneapolis, MN, USA; Division of Health Policy and Management, School of Public Health, University of Minnesota, Minneapolis, MD, USA.
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Gallagher S, Heberger JR. The effects of operator position, pallet orientation, and palletizing condition on low back loads in manual bag palletizing operations. INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS 2015; 47:84-92. [PMID: 26190879 PMCID: PMC4503528 DOI: 10.1016/j.ergon.2015.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
UNLABELLED Many mining commodities are packaged and shipped using bags. Small bags are typically loaded onto pallets for transport and require a significant amount of manual handling by workers. This specific task of manual bag handling has been associated with the development of musculoskeletal disorders (MSDs), especially low back disorders. This study evaluates the biomechanical demands of different work layouts when performing manual palletizing of small bags, and evaluates the biomechanical stresses associated with different stacking techniques. Results indicate that peak forward bending moments as well as spinal compression and shear forces are higher when the pallet is situated at the side of the conveyor as opposed to the end of the conveyor. At low levels of the pallet, controlled bag placement results in higher peak forward bending moments than stacking at higher levels and when dropping the bag to lower levels. The results of this study will be used to inform the development of an audit tool for bagging operations in the mining industry. RELEVANCE TO INDUSTRY In many cases for workers loading small bags, compression forces exceed the NIOSH criterion of 3400 N. Orientation of the pallet has a significant impact on spinal compression, and positioning the pallet at the end of the conveyor reduces the estimated compressive loading on the lumbar spine by approximately 800 N.
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Affiliation(s)
- Sean Gallagher
- Department of Industrial and Systems Engineering, Auburn University, 3304 Shelby Center, Auburn, AL 36849-5346, USA
| | - John R. Heberger
- National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health Research, 626 Cochrans Mill Road, Pittsburgh, PA 15236-0070, USA
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Boocock MG, Mawston GA, Taylor S. Age-related differences do affect postural kinematics and joint kinetics during repetitive lifting. Clin Biomech (Bristol, Avon) 2015; 30:136-43. [PMID: 25576019 DOI: 10.1016/j.clinbiomech.2014.12.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/19/2014] [Accepted: 12/19/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND Age is considered a risk factor for manual handling-related injuries and older workers incur higher injury-related costs than younger co-workers. This study investigated the differences between the kinematics and kinetics of repetitive lifting in two groups of handlers of different ages. METHODS Fourteen younger (mean 24.4 yr) and 14 older (mean 47.2 yr) males participated in the study. Participants repetitively lifted a box weighing 13 kg at a frequency of 10 lifts/min for a maximum of 20 min. Postural kinematics (joint and lumbosacral angles and angular velocities) and kinetics (joint moments) were measured throughout the lifting task using motion analysis and ground reaction forces. Muscle fatigue of the erector spinae was assessed using electromyography. FINDINGS Peak lumbosacral, trunk, hip and knee flexion angles differed significantly between age groups over the duration of the task, as did lumbosacral and trunk angular velocities. The younger group increased peak lumbar flexion by approximately 18% and approached 99% of maximum lumbosacral flexion after 20 min, whereas the older group increased lumbar flexion by 4% and approached 82% maximum flexion. The younger group had a larger increase in peak lumbosacral and trunk angular velocities during extension, which may be related to the increased back muscle fatigue observed among the younger group. INTERPRETATION Older participants appeared to control the detrimental effects of fatigue associated with repetitive lifting and limit lumbar spine range of motion. The higher rates of musculoskeletal injury among older workers may stem from a complex interaction of manual handling risk factors.
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Affiliation(s)
- Mark G Boocock
- Health and Rehabilitation Research Institute, Auckland University of Technology, New Zealand.
| | - Grant A Mawston
- Health and Rehabilitation Research Institute, Auckland University of Technology, New Zealand
| | - Steve Taylor
- Health and Rehabilitation Research Institute, Auckland University of Technology, New Zealand
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Quirk DA, Hubley-Kozey CL. Age-related changes in trunk neuromuscular activation patterns during a controlled functional transfer task include amplitude and temporal synergies. Hum Mov Sci 2014; 38:262-80. [PMID: 25457424 DOI: 10.1016/j.humov.2014.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Revised: 07/22/2014] [Accepted: 08/08/2014] [Indexed: 12/01/2022]
Abstract
While healthy aging is associated with physiological changes that can impair control of trunk motion, few studies examine how spinal muscle responses change with increasing age. This study examined whether older (over 65 years) compared to younger (20-45 years) adults had higher overall amplitude and altered temporal recruitment patterns of trunk musculature when performing a functional transfer task. Surface electromyograms from twelve bilateral trunk muscle (24) sites were analyzed using principal component analysis, extracting amplitude and temporal features (PCs) from electromyographic waveforms. Two PCs explained 96% of the waveform variance. Three factor ANOVA models tested main effects (group, muscle and reach) and interactions for PC scores. Significant (p<.0125) group interactions were found for all PC scores. Post hoc analysis revealed that relative to younger adults, older adults recruited higher agonist and antagonistic activity, demonstrated continuous activation levels in specific muscle sites despite changing external moments, and had altered temporal synergies within abdominal and back musculature. In summary both older and younger adults recruit highly organized activation patterns in response to changing external moments. Differences in temporal trunk musculature recruitment patterns suggest that older adults experience different dynamic spinal stiffness and loading compared to younger adults during a functional lifting task.
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Affiliation(s)
- D Adam Quirk
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada; School of Health and Human Performance, Dalhousie University, Halifax, NS, Canada
| | - Cheryl L Hubley-Kozey
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada; School of Health and Human Performance, Dalhousie University, Halifax, NS, Canada; School of Physiotherapy, Dalhousie University, Halifax, NS, Canada.
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Qasim M, Natarajan RN, An HS, Andersson GB. Damage accumulation location under cyclic loading in the lumbar disc shifts from inner annulus lamellae to peripheral annulus with increasing disc degeneration. J Biomech 2014; 47:24-31. [DOI: 10.1016/j.jbiomech.2013.10.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/16/2013] [Accepted: 10/12/2013] [Indexed: 10/26/2022]
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Gallagher S, Heberger JR. Examining the interaction of force and repetition on musculoskeletal disorder risk: a systematic literature review. HUMAN FACTORS 2013; 55:108-24. [PMID: 23516797 PMCID: PMC4495348 DOI: 10.1177/0018720812449648] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
OBJECTIVE Our aims were (a) to perform a systematic literature review of epidemiological studies that examined the interaction of force and repetition with respect to musculoskeletal disorder (MSD) risk, (b) to assess the relationship of force and repetition in fatigue failure studies of musculoskeletal tissues, and (c) to synthesize these findings. BACKGROUND Many epidemiological studies have examined the effects of force and repetition on MSD risk; however, relatively few have examined the interaction between these risk factors. METHOD In a literature search, we identified 12 studies that allowed evaluation of a force-repetition interaction with respect to MSD risk. Identified studies were subjected to a methodological quality assessment and critical review. We evaluated laboratory studies of fatigue failure to examine tissue failure responses to force and repetition. RESULTS Of the 12 epidemiological studies that tested a Force x Repetition interaction, 10 reported evidence of interaction. Based on these results, the suggestion is made that force and repetition may be interdependent in terms of their influence on MSD risk. Fatigue failure studies of musculoskeletal tissues show a pattern of failure that mirrors the MSD risk observed in epidemiological studies. CONCLUSIONS Evidence suggests that there may be interdependence between force and repetition with respect to MSD risk. Repetition seems to result in modest increases in risk for low-force tasks but rapid increases in risk for high-force tasks. This interaction may be representative of a fatigue failure process in affected tissues.
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Affiliation(s)
- Sean Gallagher
- Department of Industrial and Systems Engineering, Auburn University, Auburn, AL, USA.
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Ordway NR, Rim BC, Tan R, Hickman R, Fayyazi AH. Anterior cervical interbody constructs: effect of a repetitive compressive force on the endplate. J Orthop Res 2012; 30:587-92. [PMID: 22002745 DOI: 10.1002/jor.21566] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 09/19/2011] [Indexed: 02/04/2023]
Abstract
Graft subsidence following anterior cervical reconstruction can result in the loss of sagittal balance and recurring foraminal stenosis. This study examined the implant-endplate interface using a cyclic fatigue loading protocol in an attempt to model the subsidence seen in vivo. The superior endplate from 30 cervical vertebrae (C3 to T1) were harvested and biomechanically tested in axial compression with one of three implants: Fibular allograft; titanium mesh cage packed with cancellous chips; and trabecular metal. Each construct was cyclically loaded from 50 to 250 N for 10,000 cycles. Nondestructive cyclic loading of the cervical endplate-implant construct resulted in a stiffer construct independent of the type of the interbody implant tested. The trabecular metal construct demonstrated significantly more axial stability and significantly less subsidence in comparison to the titanium mesh construct. Although the allograft construct resulted in more subsidence than the trabecular metal construct, the difference was not significant and no difference was found when comparing axial stability. For all constructs, the majority of the subsidence during the cyclic testing occurred during the first 500 cycles and was followed by a more gradual settling in the remaining 9,500 cycles.
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Affiliation(s)
- Nathaniel R Ordway
- Department of Orthopedic Surgery, SUNY Upstate Medical University, 750 East Adams Streets, Syracuse, 13201 New York, USA.
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Campbell-Kyureghyan NH, Yalla SV, Voor M, Burnett D. Effect of orientation on measured failure strengths of thoracic and lumbar spine segments. J Mech Behav Biomed Mater 2011; 4:549-57. [DOI: 10.1016/j.jmbbm.2011.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 01/03/2011] [Accepted: 01/03/2011] [Indexed: 11/28/2022]
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Huber G, Skrzypiec DM, Klein A, Püschel K, Morlock MM. High cycle fatigue behaviour of functional spinal units. INDUSTRIAL HEALTH 2010; 48:550-556. [PMID: 20953072 DOI: 10.2486/indhealth.mswbvi-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Vibrations have been shown to be an important risk factor for spinal pathologies. The underlying mechanisms are poorly understood and in vivo data scarce and difficult to obtain. Consequently numerical models are used to estimate spinal loading; requiring fatigue strength information, which was obtained in this study for spinal specimens from young and old male donors of working age in vitro. Bone mineral density (BMD) and endplate area were determined using CT scans. Three groups were investigated: young specimens in neutral posture, young in flexed posture, and old in neutral posture. The loading consisted of 300,000 sinusoidal compression cycles of 2 kN, inducing a nucleus pressure peek of approximately 1.4 MPa. No failure of the young specimens in neutral posture was observed, but four specimens from older donors with low BMD failed. The product between endplate area and BMD was shown to be useful to predict fatigue strength for old donors and should therefore be considered with regard to whole body vibration injuries. In flexed posture, two specimens from young donors failed. One failure can be attributed to low BMD following the trend for the old specimens; the other failure could not be explained, leaving the influence of flexion yet unclear.
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Affiliation(s)
- Gerd Huber
- Institute of Biomechanics, TUHH Hamburg University of Technology, Denickestrasse 15, 21073 Hamburg, Germany.
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