1
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Armstrong DP, Davidson JB, Fischer SL. Determining whether biomechanical variables that describe common 'safe lifting' cues are associated with low back loads. J Electromyogr Kinesiol 2024; 75:102867. [PMID: 38325138 DOI: 10.1016/j.jelekin.2024.102867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 01/17/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024] Open
Abstract
Lift technique training programs have been implemented to help reduce injury risk, but the underlying content validity of cues used within these programs is not clear. The objective of this study was to determine whether biomechanical variables, that commonly used lifting cues aim to elicit, are associated with resultant low back extensor moment exposures. A sample of 72 participants were recruited to perform 10 repetitions of a floor-to-waist height barbell lift while whole-body kinematics and ground reaction forces were collected. Kinematic, kinetic, and energetic variables representative of characteristics commonly targeted by lifting cues were calculated as predictor variables, while peak and cumulative low back moments were calculated as dependent measures. Multiple regression revealed that 56.6-59.2% of variance in low back moments was explained by predictor variables. From these regression models, generating motion with the legs (both greater hip and knee work), minimizing the horizontal distance of the body to the load, maintaining a stable body position, and minimizing lift time were associated with lower magnitudes of low back moments. These data support that using cues targeting these identified variables may be more effective at reducing peak low back moment exposures via lift training.
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Affiliation(s)
- Daniel P Armstrong
- Department of Kinesiology, Faculty of Health Sciences, University of Waterloo, Waterloo, Canada
| | - Justin B Davidson
- Department of Kinesiology, Faculty of Health Sciences, University of Waterloo, Waterloo, Canada
| | - Steven L Fischer
- Department of Kinesiology, Faculty of Health Sciences, University of Waterloo, Waterloo, Canada.
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2
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Zehr JD, Davidson JM, Callaghan JP. Implementing an accelerometer-based pelvis segment for low back kinetic analyses during dynamic movement tasks. J Biomech 2024; 166:112060. [PMID: 38537369 DOI: 10.1016/j.jbiomech.2024.112060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 03/17/2024] [Accepted: 03/21/2024] [Indexed: 04/13/2024]
Abstract
An accelerometer-based pelvis has been employed to study segment and joint kinematics during scenarios involving close human-object interface and/or line-of-sight obstructions. However, its accuracy for examining low back kinetic outcomes is unknown. This study compared reaction moments and contact forces of the L5S1 joint calculated with an accelerometer-based and optically tracked pelvis segment. An approach to correct the global pelvis position as a function of thigh angle was developed. One participant performed four dynamic tasks: forward bend, squat, sit-to-stand-to-sit, and forward lunge. A standard bottom-up inverse dynamics approach was used and the root mean square error (RMSE) and coefficient of determination (R2) were calculated to examine kinetic differences between the optical and accelerometer approaches. The RMSE observed for L5S1 reaction flexion-extension moments ranged from 1.32 Nm to 2.20 Nm (R2 ≥ 0.98). The RMSE for net shear and compression reaction forces ranged from 2.13 to 10.45 N and 0.63 - 4.96 N, respectively. Similarly, the RMSE for L5S1 joint contact shear and compression ranged from 13.45 N to 19.51 N (R2 ≥ 0.85) and 31.18 N - 55.97 N (R2 ≥ 0.97), respectively. In conclusion, the accelerometer-based pelvis together with the approach to correct the global pelvis position is a feasible approach for computing low back kinetics with a single equivalent muscle model. The observed error in joint contact forces represents less than 5 % of the NIOSH recommended action limits and is unlikely to alter the interpretation of low back injury risk.
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Affiliation(s)
- Jackie D Zehr
- Human Performance Lab, University of Calgary, Calgary, Alberta, Canada
| | - Jessa M Davidson
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Jack P Callaghan
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, Ontario, Canada.
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3
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Armstrong DP, Beach TAC, Fischer SL. The Influence of Contextual and Theoretical Expertise on Generic and Occupation-Specific Lifting Strategy. HUMAN FACTORS 2024:187208231223429. [PMID: 38299447 DOI: 10.1177/00187208231223429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
OBJECTIVE To determine whether (i) low back loads and/or (ii) kinematic coordination patterns differed across theoretical expert, contextual expert and novice groups when completing both generic and occupation-specific lifts. BACKGROUND Experience has been proposed as a factor that could reduce biomechanical exposures in lifting, but the literature reports mixed effects. The inconsistent relationship between experience and exposures may be partially attributable to the broad classification of experience and experimental lifting protocols not replicating the environment where experience was gained. METHODS Purposive sampling was used to recruit 72 participants including theoretical experts (formal training on lifting mechanics), contextual experts (paramedics), and novices. Participants performed 10 barbell and crate (generic) lifts, as well as backboard and stretcher (occupation-specific) lifts while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear loads normalized to body mass, as well as kinematic coordination patterns, were calculated as dependent variables. RESULTS No significant differences in low back loads were observed across expertise groups. However, significant differences were seen in kinematic coordination patterns across expertise groups in occupation-specific lifts, but not in generic lifts. CONCLUSION Increasing expertise is unlikely to minimize low back loads in lifting. However, contextual expertise did influence lifting kinematics, but only when performing occupationally specific lifts. APPLICATION Contextual expertise may help lifters adopt lifting kinematics that enhance the tolerance of their musculoskeletal system to withstand applied loads, but does not seem to reduce the applied low back loads relative to noncontextual expert groups.
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Armstrong DP, Beach TAC, Fischer SL. Quantifying how functional and structural personal factors influence biomechanical exposures in paramedic lifting tasks. ERGONOMICS 2023:1-16. [PMID: 37830870 DOI: 10.1080/00140139.2023.2270728] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 09/12/2023] [Indexed: 10/14/2023]
Abstract
It is unknown how structural (sex, stature, body mass) and functional (strength, flexibility) personal factors influence lifting strategy in paramedic work. We explored whether variance in peak low back forces and kinematic coordination patterns could be explained by structural and functional personal factors in paramedic lifting tasks. Seventy-two participants performed backboard and stretcher lifts. Peak low back forces normalised to body mass, as well as kinematic coordination patterns, were calculated as dependent variables. Being female, stronger, shorter, having higher body mass, and/or having greater lower body range of motion (ROM) were all independently associated with lower normalised low back forces across backboard and stretcher lifting. Females and stronger individuals seemed to define a movement objective to consistently minimise compressive forces, while individuals with greater hip ROM consistently minimised anteroposterior shear forces. The efficacy of improving strength and hip ROM to reduce low back forces in paramedic lifting should be investigated.Practitioner summary: Females, stronger individuals, and individuals with greater hip range of motion consistently exhibited lower normalised low back forces in paramedic lifting. Improving strength and hip range of motion via training is a potential proactive ergonomics approach to reduce peak low back forces in paramedic lifting tasks.
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Affiliation(s)
- Daniel P Armstrong
- Department of Kinesiology, Faculty of Health Sciences, University of Waterloo, Waterloo, Canada
| | - Tyson A C Beach
- Department of Kinesiology, Faculty of Health Sciences, University of Waterloo, Waterloo, Canada
| | - Steven L Fischer
- Department of Kinesiology, Faculty of Health Sciences, University of Waterloo, Waterloo, Canada
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An Enhanced Planar Linked Segment Model for Predicting Lumbar Spine Loads during Symmetric Lifting Tasks. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10196700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present technical note aimed at enriching the planar linked segment model originally proposed by Chaffin with the prediction of the moment arm and of the orientation of the line of action of the back extensor muscles during symmetric lifting tasks. The prediction equations proposed by van Dieen and de Looze for their single equivalent muscle model were used for such a purpose. Their prediction was based on the thorax-to-pelvis flexion angle as computed from 3D video-based motion capture. In order to make these prediction equations compliant with a two-dimensional analysis, the planar angle formed by the segment joining L5/S1 to the shoulder with the longitudinal axis of the pelvis was introduced. This newly computed planar trunk flexion angle was used to feed van Dieen and de Looze’s equations, comparing the results with the original model. A full-body Plug-in-Gait model relative to 10 subjects performing manual lifting activities using a stoop and a squat technique was used for model validation. A strong association was found between the proposed planar trunk flexion angle and that used by van Dieen and de Looze (r = 0.970). A strong association and a high level of agreement were found between the back extensor muscle moment arm (r = 0.965; bias < 0.001 m; upper limit of agreement (LOA) = 0.002 m; lower LOA < 0.001 m) and the orientation of the line of action (r = 0.970; bias = 2.8°; upper LOA = 5.3°; lower LOA = 0.2°) as computed using the two methods. For both the considered variables, the prediction error fell within the model sensitivity.
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Edington C, Greening C, Kmet N, Philipenko N, Purves L, Stevens J, Lanovaz J, Butcher S. The Effect of Set Up Position on EMG Amplitude, Lumbar Spine Kinetics, and Total Force Output During Maximal Isometric Conventional-Stance Deadlifts. Sports (Basel) 2018; 6:sports6030090. [PMID: 30200300 PMCID: PMC6162543 DOI: 10.3390/sports6030090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 11/16/2022] Open
Abstract
The purpose of this study was to examine the biomechanical differences between two set up variations during the isometric initiation of conventional barbell deadlifts (DL): Close-bar DL (CBDL), where the bar is positioned above the navicular, and far-bar DL (FBDL), where the bar is placed above the 3rd metatarsophalangeal joint. A cross-sectional, randomized, within-participant pilot study was used. Experienced powerlifters and weightlifters (n = 10) performed three individual isometric pulls of the initiation of both conditions. The CBDL resulted in lower tibia and knee angles and greater pelvis and torso angles than the FBDL (p < 0.05), as well as greater electromyography (EMG) activity in the biceps femoris and upper lumbar erector spinae, but lower activity in the vastus lateralis, and a lower knee extensor moment (p < 0.05). There were no statistical differences for ground reaction force, joint reaction lumbar shear and compression forces between the two conditions. Despite the differences in pelvis and torso angles between lifting conditions, the internal joint net moment, internal shear forces, and internal compressive forces were not different between the two lifting styles. The CBDL set up also resulted in greater posterior chain (hamstrings and erector spine) EMG amplitude, whereas the FBDL set up resulted in more anterior chain (quadriceps) amplitude. Lifters and coaches may choose either deadlift style, according to preferences or training goals, without concern for differences in lumbar spinal loading.
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Affiliation(s)
- Corey Edington
- College of Kinesiology, University of Saskatchewan, Saskatoon, SK S7N 5B2, Canada.
| | - Cassandra Greening
- School of Rehabilitation Science, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 0Z4, Canada.
| | - Nick Kmet
- School of Rehabilitation Science, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 0Z4, Canada.
| | - Nadia Philipenko
- School of Rehabilitation Science, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 0Z4, Canada.
| | - Lindsay Purves
- School of Rehabilitation Science, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 0Z4, Canada.
| | - Jared Stevens
- School of Rehabilitation Science, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 0Z4, Canada.
| | - Joel Lanovaz
- College of Kinesiology, University of Saskatchewan, Saskatoon, SK S7N 5B2, Canada.
| | - Scotty Butcher
- School of Rehabilitation Science, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK S7N 0Z4, Canada.
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Lad U, Oomen NMCW, Callaghan JP, Fischer SL. Comparing the biomechanical and psychophysical demands imposed on paramedics when using manual and powered stretchers. APPLIED ERGONOMICS 2018; 70:167-174. [PMID: 29866307 DOI: 10.1016/j.apergo.2018.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 02/28/2018] [Accepted: 03/01/2018] [Indexed: 06/08/2023]
Abstract
The aim of this investigation was to compare the effect of three different stretchers (two powered and one manual) on the biomechanical and psychophysical demands experienced by paramedics when performing routine stretcher handling activities. Eight experienced paramedics performed stretcher raising, lowering, unloading and loading tasks. Video data of task performance and static force requirements were recorded and input into a posture matching program with a quasi-static linked segment model (3DMatch) to compute peak and cumulative L4/L5 compression and shear forces and shoulder moments during each activity. Ratings of perceived exertion (RPE) were recorded from paramedics upon the completion of each task. Use of powered stretchers with load assist functionality reduced the demands on paramedics. Peak L4/L5 forces were reduced by 13-62% and 58-93% for compression and shear respectively when using powered stretchers to perform routine stretcher handling activities. Shoulder flexor moments and RPE scores were reduced by 16-95% and 29-60% respectively when using the powered stretchers compared to the manual stretcher. However, cumulative forces showed mixed results. Although powered stretcher use decreased peak forces, loading and unloading a powered stretcher took 1.5 to 3.4 times longer then when using the manual stretcher, which may explain the mixed results regarding cumulative forces. Based on the RPE scores, paramedics preferred power stretchers relative to the manual stretcher. This study demonstrates that powered stretchers can reduce peak biomechanical and psychophysical exposures associated with the development of musculoskeletal disorder (MSD) during routine stretcher handling activities with minimal increases in cumulative exposures.
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Affiliation(s)
- Uma Lad
- University of Waterloo, Department of Kinesiology, 300 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - Nathalie M C W Oomen
- University of Waterloo, Department of Kinesiology, 300 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - Jack P Callaghan
- University of Waterloo, Department of Kinesiology, 300 University Avenue West, Waterloo, ON, N2L 3G1, Canada
| | - Steven L Fischer
- University of Waterloo, Department of Kinesiology, 300 University Avenue West, Waterloo, ON, N2L 3G1, Canada.
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8
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Zehr JD, Howarth SJ, Beach TA. Using relative phase analyses and vector coding to quantify Pelvis-Thorax coordination during lifting—A methodological investigation. J Electromyogr Kinesiol 2018; 39:104-113. [DOI: 10.1016/j.jelekin.2018.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/30/2017] [Accepted: 02/11/2018] [Indexed: 10/18/2022] Open
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9
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Zehr JD, Carnegie DR, Welsh TN, Beach TAC. A comparative analysis of lumbar spine mechanics during barbell- and crate-lifting: implications for occupational lifting task assessments. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2018; 26:1-8. [DOI: 10.1080/10803548.2018.1439872] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Jackie D. Zehr
- Department of Kinesiology, University of Waterloo, Canada
| | | | - Timothy N. Welsh
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
| | - Tyson A. C. Beach
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
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10
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Beach TAC, Stankovic T, Carnegie DR, Micay R, Frost DM. Using verbal instructions to influence lifting mechanics - Does the directive "lift with your legs, not your back" attenuate spinal flexion? J Electromyogr Kinesiol 2017; 38:1-6. [PMID: 29107836 DOI: 10.1016/j.jelekin.2017.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 08/02/2017] [Accepted: 10/19/2017] [Indexed: 11/15/2022] Open
Abstract
"Use your legs" is commonly perceived as sound advice to prevent lifting-related low-back pain and injuries, but there is limited evidence that this directive attenuates the concomitant biomechanical risk factors. Body segment kinematic data were collected from 12 men and 12 women who performed a laboratory lifting/lowering task after being provided with different verbal instructions. The main finding was that instructing participants to lift "without rounding your lower back" had a greater effect on the amount of spine flexion they exhibited when lifting/lowering than instructing them to lift "with your legs instead of your back" and "bend your knees and hips". It was concluded that if using verbal instructions to discourage spine flexion when lifting, the instructions should be spine- rather than leg-focused.
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Affiliation(s)
- Tyson A C Beach
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario M5S 2W6, Canada
| | - Tatjana Stankovic
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario M5S 2W6, Canada
| | - Danielle R Carnegie
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario M5S 2W6, Canada
| | - Rachel Micay
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario M5S 2W6, Canada
| | - David M Frost
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario M5S 2W6, Canada.
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11
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Southwell DJ, Petersen SA, Beach TA, Graham RB. The effects of squatting footwear on three-dimensional lower limb and spine kinetics. J Electromyogr Kinesiol 2016; 31:111-118. [DOI: 10.1016/j.jelekin.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 10/06/2016] [Accepted: 10/10/2016] [Indexed: 10/20/2022] Open
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12
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van Dieën JH, Hoozemans MJ, van der Burg P, Jansen JP, Kingma I, Kuijer P. The Importance of Antagonistic Cocontraction of Trunk Muscles for Spinal Loads during Lifting and Pulling Tasks: Implications for Modeling Approaches. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/154193120004402857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Jaap H. van Dieën
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, ‘Vrije Universiteit’, Amsterdam, The Netherlands
| | - Marco J.M. Hoozemans
- Coronel Institute for Occupational and Environmental Health, Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands
| | - Petra van der Burg
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, ‘Vrije Universiteit’, Amsterdam, The Netherlands
| | - Jorrit P. Jansen
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, ‘Vrije Universiteit’, Amsterdam, The Netherlands
| | - Idsart Kingma
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, ‘Vrije Universiteit’, Amsterdam, The Netherlands
| | - Paul Kuijer
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, ‘Vrije Universiteit’, Amsterdam, The Netherlands
- Coronel Institute for Occupational and Environmental Health, Academic Medical Center/University of Amsterdam, Amsterdam, The Netherlands
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Abstract
An ambulatory monitor for physical low back load exposure should be non-interfering, unrestricted in application space or duration, practical in use and interpretation, sufficiently accurate and reliable, sensitive to load handling and load coping and offer both detailed load parameters statistics and global information on tasks and behavior. A method is introduced that tries to meet these demands applying 3 technological innovations: miniature inertial movement sensing, artificial neural network based automatic calibration of the dynamic surface EMG–moment relationship and miniature RF links for wireless video-synchronization (AMBER). The currently implemented ambulatory method assesses load exposure through absolute 3D trunk kinematics data, muscle activation patterns, net moment data at spinal level L5/S1, compressive forces in symmetric loading situations and synchronized video. Principles, validation and recent field applications of the method are presented.
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Affiliation(s)
- Chris T.M. Baten
- Roessingh Research and Development, Enschede, Netherlands PO Box 310, 7500AH Enschede The Netherlands
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Kingma I, Kuijer PPF, Hoozemans MJ, Van Dieën JH, Van Der Beek AJ, Van Der Frings-Dresen MH. Effect of Center of Mass and Handle Location of Two-Wheeled Refuse Containers on Mechanical Loading. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/154193120004402863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of the current study was to find out how the center of mass (COM) and handle location of a two-wheeled container affects handle forces and joint loading. Forces at the handles and joint loading were quantified in four subjects during steady, two-handed pushing and pulling of two-wheeled containers with nine different COM locations and eleven different handle locations. The COM location turned out to have a major influence on handle forces and joint loading, whereas the influence of the handle location was moderate. Subjects considerably adapted the tilt angle of the container in response to variations in handle location but hardly in response to variations in COM location. For two-handed pushing and pulling the current design of a two-wheeled container can be improved by moving the centre of mass of the loaded container in the direction of the axis of the wheels and by slightly increasing the height of the handles.
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Affiliation(s)
- Idsart Kingma
- Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - P. Paul F.M. Kuijer
- Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
- Coronel Institute for Occupational and Environmental Health, Academic Medical Center / University of Amsterdam, Amsterdam, The Netherlands
| | - Marco J.M. Hoozemans
- Coronel Institute for Occupational and Environmental Health, Academic Medical Center / University of Amsterdam, Amsterdam, The Netherlands
| | - Jaap H. Van Dieën
- Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | | | - Monique H.W. Van Der Frings-Dresen
- Coronel Institute for Occupational and Environmental Health, Academic Medical Center / University of Amsterdam, Amsterdam, The Netherlands
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Dreischarf M, Shirazi-Adl A, Arjmand N, Rohlmann A, Schmidt H. Estimation of loads on human lumbar spine: A review of in vivo and computational model studies. J Biomech 2016; 49:833-845. [DOI: 10.1016/j.jbiomech.2015.12.038] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 01/09/2023]
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Zander T, Dreischarf M, Schmidt H. Sensitivity analysis of the position of the intervertebral centres of reaction in upright standing – a musculoskeletal model investigation of the lumbar spine. Med Eng Phys 2016; 38:297-301. [DOI: 10.1016/j.medengphy.2015.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/20/2015] [Accepted: 12/08/2015] [Indexed: 10/22/2022]
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17
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Suehiro T, Mizutani M, Okamoto M, Ishida H, Kobara K, Fujita D, Osaka H, Takahashi H, Watanabe S. Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion. J Phys Ther Sci 2014; 26:1895-8. [PMID: 25540492 PMCID: PMC4273052 DOI: 10.1589/jpts.26.1895] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/09/2014] [Indexed: 11/24/2022] Open
Abstract
[Purpose] This study investigated the selective activation of the gluteus maximus during
a prone hip extension with knee flexion exercise, with the hip joint in different
positions. [Subjects] The subjects were 21 healthy, male volunteers. [Methods] Activities
of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and
bilateral lumbar multifidus were measured using surface electromyography during a prone
hip extension with knee flexion exercise. Measurements were made with the hip joint in
each of 3 positions: (1) a neutral hip joint position, (2) an abduction hip joint
position, and (3) an abduction with external rotation hip joint position. [Results]
Gluteus maximus activity was significantly higher when the hip was in the abduction with
external rotation hip joint position than when it was in the neutral hip joint and
abduction hip joint positions. Gluteus maximus activity was also significantly higher in
the abduction hip joint position than in the neutral hip joint position. Hamstring
activity was significantly lower when the hip was in the abduction with external rotation
hip joint position than when it was in the neutral hip joint and abduction hip joint
positions. [Conclusion] Abduction and external rotation of the hip during prone hip
extension with knee flexion exercise selectively activates the gluteus maximus.
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Affiliation(s)
- Tadanobu Suehiro
- Graduate School of Health Sciences, Kibi International University, Japan ; Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
| | - Masatoshi Mizutani
- Graduate School of Health Sciences, Kibi International University, Japan
| | | | - Hiroshi Ishida
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
| | - Kenichi Kobara
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
| | - Daisuke Fujita
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
| | - Hiroshi Osaka
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
| | - Hisashi Takahashi
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
| | - Susumu Watanabe
- Department of Rehabilitation, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Japan
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Arab AM, Ghamkhar L, Emami M, Nourbakhsh MR. Altered muscular activation during prone hip extension in women with and without low back pain. Chiropr Man Therap 2011; 19:18. [PMID: 21838925 PMCID: PMC3188886 DOI: 10.1186/2045-709x-19-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Accepted: 08/14/2011] [Indexed: 11/11/2022] Open
Abstract
Background Altered movement pattern has been associated with the development of low back pain (LBP). The purpose of this study was to investigate the activity pattern of the ipsilateral erector spinae (IES) and contralateral erectorspinae (CES), gluteus maximus (GM) and hamstring (HAM) muscles during prone hip extension (PHE) test in women with and without LBP. A cross-sectional non-experimental design was used. Methods Convenience sample of 20 female participated in the study. Subjects were categorized into two groups: with LBP (n = 10) and without LBP (n = 10). The electromyography (EMG) signal amplitude of the tested muscles during PHE (normalized to maximum voluntary electrical activity (MVE)) was measured in the dominant lower extremity in all subjects. Results Statistical analysis revealed greater normalized EMG signal amplitude in women with LBP compared to non-LBP women. There was significant difference in EMG activity of the IES (P = 0.03) and CES (P = 0.03) between two groups. However, no significant difference was found in EMG signals of the GM (P = 0.11) and HAM (P = 0.14) among two groups. Conclusion The findings of this study demonstrated altered activation pattern of the lumbo-pelvic muscles during PHE in the women with chronic LBP. This information is important for investigators using PHE as either an evaluation tool or a rehabilitation exercise.
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Affiliation(s)
- Amir M Arab
- Department of Physical Therapy, University of Social Welfare and Rehabilitation Sciences, Evin, Tehran, Iran.
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Howarth SJ, Beach TA, Callaghan JP. Dynamic factors and force-weighting corrections influence estimates of cumulative vertebral joint compression. THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2010. [DOI: 10.1080/14639220902862675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Howarth SJ, Beach TAC, Pearson AJ, Callaghan JP. Using sitting as a component of job rotation strategies: are lifting/lowering kinetics and kinematics altered following prolonged sitting. APPLIED ERGONOMICS 2009; 40:433-439. [PMID: 19081557 DOI: 10.1016/j.apergo.2008.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 10/15/2008] [Accepted: 10/27/2008] [Indexed: 05/27/2023]
Abstract
Workers are often required to perform manual materials handling tasks immediately following periods of prolonged sitting either as a secondary job component of as different tasks in a job rotation strategy. The goal of this investigation was to determine if changes to low-back kinetics and/or kinematics occurred during repetitive lifting/lowering exertions following extended seated exposures. Upper body kinematics, lumbar spine flexion angle, pelvic orientation and bilateral muscle activity from the external abdominal obliques and lumbar erector spinae were recorded for 8 males and 8 females while they alternated between sessions of repetitive lifting/lowering and prolonged sitting. Upper body kinematics were used as inputs to a linked segment model to compute low-back flexion/extension moments, compression, and shear. Peak lumbar flexion was reduced by 1.8 degrees during the lifting/lowering exertions following the first hour of sitting which consequently led to a reduction of approximately 50N in the reaction anteroposterior shear forces. Sitting postures were consistent with previously reported data. The reduced shear loads during repetitive lift/lower exertions following prolonged sitting may be a consequence of alterations in passive tissue properties which could alter the risk of low-back injury, although future research is required to examine the biomechanical significance of this finding. Changes to both kinematics and kinetics were minimal suggesting that using prolonged sitting as a component of a task series in job rotation does not alter the risk present when combined with repetitive lifting tasks.
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Affiliation(s)
- Samuel J Howarth
- Faculty of Applied Health Sciences, Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Beach TA, Howarth SJ, Callaghan JP. Muscular contribution to low-back loading and stiffness during standard and suspended push-ups. Hum Mov Sci 2008; 27:457-72. [DOI: 10.1016/j.humov.2007.12.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 12/10/2007] [Accepted: 12/26/2007] [Indexed: 10/22/2022]
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Cargill SC, Pearcy M, Barry MD. Three-dimensional lumbar spine postures measured by magnetic resonance imaging reconstruction. Spine (Phila Pa 1976) 2007; 32:1242-8. [PMID: 17495783 DOI: 10.1097/01.brs.0000263404.66369.a5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Investigation of method. OBJECTIVE This study presents a novel method of accurately determining relative bone position in vivo using magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA Biomechanical modeling of the human body requires measurement of the relative positions of skeletal elements. Spinal orientation is particularly difficult to measure due to small joint movements, relative inaccessibility of the bones to direct measurement, and joint complexity. METHODS A process incorporating both positional and conventional MRI was used to measure the skeletal positions of the lumbar spine and pelvis. The method uses higher quality conventional MRI to determine bone geometries and then registers these with lower resolution, positional MRI images of various postures to determine the relative locations of the bones. Flexion/extension, lateral bend, and axial twist rotations were measured for each joint. RESULTS The results indicate good intrameasurer reliability, with a maximum rotational difference for all vertebral registrations of less than 1 degrees and a maximum translational difference of less than 3 mm. While there did not appear to be significant patterns between the 2 Subjects, there were trends within each Subject as well as identifiable postural characteristics. CONCLUSIONS Although processing times are currently lengthy, the data collected are 3-dimensional, and represent the anatomy and movement of a specific individual.
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Affiliation(s)
- Sara C Cargill
- School of Engineering Systems and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
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Kingma I, Staudenmann D, van Dieën JH. Trunk muscle activation and associated lumbar spine joint shear forces under different levels of external forward force applied to the trunk. J Electromyogr Kinesiol 2007; 17:14-24. [PMID: 16531071 DOI: 10.1016/j.jelekin.2005.12.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 11/23/2005] [Accepted: 12/01/2005] [Indexed: 01/23/2023] Open
Abstract
High anterior intervertebral shear loads could cause low back injuries and therefore the neuromuscular system may actively counteract these forces. This study investigated whether, under constant moment loading relative to L3L4, an increased externally applied forward force on the trunk results in a shift in muscle activation towards the use of muscles with more backward directed lines of action, thereby reducing the increase in total joint shear force. Twelve participants isometrically resisted forward forces, applied at several locations on the trunk, while moments were held constant relative to L3L4. Surface EMG and lumbar curvature were measured, and an EMG-driven muscle model was used to calculate compression and shear forces at all lumbar intervertebral joints. Larger externally applied forward forces resulted in a flattening of the lumbar lordosis and a slightly more backward directed muscle force. Furthermore, the overall muscle activation increased. At the T12L1 to L3L4 joint, resulting joint shear forces remained small (less than 200N) because the average muscle force pulled backward relative to those joints. However, at the L5S1 joint the average muscle force pulled the trunk forward so that the increase in muscle force with increasing externally applied forward force caused a further rise in shear force (by 102.1N, SD=104.0N), resulting in a joint shear force of 1080.1N (SD=150.4N) at 50Nm moment loading. It is concluded that the response of the neuromuscular system to shear force challenges tends to increase rather than reduce the shear loading at the lumbar joint that is subjected to the highest shear forces.
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Affiliation(s)
- Idsart Kingma
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands.
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Arjmand N, Shirazi-Adl A, Bazrgari B. Wrapping of trunk thoracic extensor muscles influences muscle forces and spinal loads in lifting tasks. Clin Biomech (Bristol, Avon) 2006; 21:668-75. [PMID: 16678948 DOI: 10.1016/j.clinbiomech.2006.03.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 03/10/2006] [Accepted: 03/14/2006] [Indexed: 02/07/2023]
Abstract
BACKGROUND An improved assessment of risk of spinal injury during lifting activities depends on an accurate estimation of trunk muscle forces, spinal loads and stability margin which in turn requires, amongst others, an accurate description of trunk muscle geometries. The lines of action of erector spinae muscles are often assumed to be linear despite the curved paths of these muscles in forward flexion postures. METHODS A novel approach was introduced that allowed for the proper simulation of curved paths for global extensor muscles in our Kinematics-driven finite element model. The lever arms of global muscles at different levels were restrained either to remain the same or decrease only by 10% relative to their respective values in upright posture. Based on our earlier measurements, static lifting tasks at two trunk flexions (40 degrees and 65 degrees ) and three lumbar postures (free style, lordotic and kyphotic) with 180 N in hands were analyzed. FINDINGS Muscle forces and spinal compression at all levels substantially decreased as the global extensor muscles took curved paths. In contrast, the shear force at lower levels increased. Allowing for a 10% reduction in these lever arms during flexion increased muscle forces and compression forces at all levels. Despite smaller muscle forces, wrapping of global muscles slightly improved the spinal stability. INTERPRETATION Consideration of global extensor muscles with curved paths and realistic lever arms is important in biomechanical analysis of lifting tasks. Reduction in the erector spinae lever arms during flexion tasks could vary depending on the lumbar posture. Results advocate small flattening of the lumbar curvature in isometric lifts yielding smaller compression and shear forces at the critical L5-S1 level.
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Affiliation(s)
- N Arjmand
- Division of Applied Mechanics, Department of Mechanical Engineering, Ecole Polytechnique, P.O. Box 6079, Station centre-ville, Montréal, Que., Canada H3C 3A7
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van Dieën JH, Kingma I, van der Bug P, van der Bug JCE. Evidence for a role of antagonistic cocontraction in controlling trunk stiffness during lifting. J Biomech 2004; 36:1829-36. [PMID: 14614936 DOI: 10.1016/s0021-9290(03)00227-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Activity of the abdominal muscles during symmetric lifting has been a consistent finding in many studies. It has been hypothesized that this antagonistic coactivation increases trunk stiffness to provide stability to the spine. To test this, we investigated whether abdominal activity in lifting is increased in response to destabilizing conditions. Ten healthy male subjects lifted 35 l containers containing 15 l of water (unstable condition), or ice (stable condition). 3D-kinematics, ground reaction forces, and EMG of selected trunk muscles were recorded. Euler angles of the thorax relative to the pelvis were determined. Inverse dynamics was used to calculate moments about L5S1. Averaged normalized abdominal EMG activity was calculated to express coactivation and an EMG-driven trunk muscle model was used to estimate the flexor moment produced by these muscles and to estimate the L5S1 compression force. Abdominal coactivation was significantly higher when lifting the unstable load. This coincided with significant increases in estimated moments produced by the antagonist muscles and in estimated compression forces on the L5S1 disc, except at the instant of the peak moment about L5S1. The lifting style was not affected by load instability as evidenced by the absence of effects on moments about L5S1 and angles of the thorax relative to the pelvis. The data support the interpretation of abdominal cocontraction during lifting as subserving spinal stability. An alternative function of the increased trunk stiffness due to cocontraction might be to achieve more precise control over the trajectory of lifted weight in order to avoid sloshing of the water mass in the box and the consequent perturbations.
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Affiliation(s)
- Jaap H van Dieën
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Van der Boechorststraat 9, Vrije Universiteit, Amsterdam BT 1081, Netherlands.
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Kingma I, van Dieën JH. Lifting over an obstacle: effects of one-handed lifting and hand support on trunk kinematics and low back loading. J Biomech 2004; 37:249-55. [PMID: 14706328 DOI: 10.1016/s0021-9290(03)00248-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mechanical loading of the low back during lifting is a common cause of low back pain. In this study two-handed lifting is compared to one-handed lifting (with and without supporting the upper body with the free hand) while lifting over an obstacle. A 3-D linked segment model was combined with an EMG-assisted trunk muscle model to quantify kinematics and joint loads at the L5S1 joint. Peak total net moments (i.e., the net moment effect of all muscles and soft tissue spanning the joint) were found to be 10+/-3% lower in unsupported one-handed lifting compared to two-handed lifting, and 30+/-8% lower in supported compared to unsupported one-handed lifting. L5S1 joint forces also showed reductions, but not of the same magnitude (18+/-8% and 15+/-10%, respectively, for compression forces, and 15+/-17% and 11+/-14% respectively, for shear forces). Those reductions of low back load were mainly caused by a reduction of trunk and load moment arms relative to the L5S1 joint during peak loading, and, in the case of hand support, by a support force of about 250 N. Stretching one leg backward did not further reduce low back load estimates. Furthermore, one-handed lifting caused an 6+/-8 degrees increase in lateral flexion, a 9+/-5 degrees increase in twist and a 6+/-6 degrees decrease in flexion. Support with the free hand caused a small further increase in lumbar twisting. It is concluded that one-handed lifting, especially with hand support, reduces L5S1 loading but increases asymmetry in movements and moments about the lumbar spine.
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Affiliation(s)
- Idsart Kingma
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, Amsterdam 1081 BT, The Netherlands.
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27
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Hoozemans MJM, Kuijer PPFM, Kingma I, van Dieën JH, de Vries WHK, van der Woude LHV, Veeger DJHEJ, van der Beek AJ, Frings-Dresen MHW. Mechanical loading of the low back and shoulders during pushing and pulling activities. ERGONOMICS 2004; 47:1-18. [PMID: 14660215 DOI: 10.1080/00140130310001593577] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The objective of this study was to quantify the mechanical load on the low back and shoulders during pushing and pulling in combination with three task constraints: the use of one or two hands, three cart weights, and two handle heights. The second objective was to explore the relation between the initial and sustained exerted forces and the mechanical load on the low back and shoulders. Detailed biomechanical models of the low back and shoulder joint were used to estimate mechanical loading. Using generalized estimating equations (GEE) the effects were quantified for exerted push/pull forces, net moments at the low back and shoulders, compressive and shear forces at the low back, and compressive forces at the glenohumeral joint. The results of this study appeared to be useful to estimate ergonomics consequences of interventions in the working constraints during pushing and pulling. Cart weight as well as handle height had a considerable effect on the mechanical load and it is recommended to maintain low cart weights and to push or pull at shoulder height. Initial and sustained exerted forces were not highly correlated with the mechanical load at the low back and shoulders within the studied range of the exerted forces.
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Affiliation(s)
- Marco J M Hoozemans
- Coronel Institute for Occupational and Envrionmental Health, AmCOGG Amsterdam Centre for Research into Health and Health Care, Academic Medical Centre/University of Amsterdam, PO box 22700, 1100 DE Amsterdam, The Netherlands
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Jorgensen MJ, Marras WS, Gupta P, Waters TR. Effect of torso flexion on the lumbar torso extensor muscle sagittal plane moment arms. Spine J 2003; 3:363-9. [PMID: 14588948 DOI: 10.1016/s1529-9430(03)00140-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Accurate anatomical inputs for biomechanical models are necessary for valid estimates of internal loading. The magnitude of the moment arm of the lumbar erector muscle group is known to vary as a function of such variables as gender. Anatomical evidence indicates that the moment arms decrease during torso flexion. However, moment arm estimates in biomechanical models that account for individual variability have been derived from imaging studies from supine postures. PURPOSE Quantify the sagittal plane moment arms of the lumbar erector muscle group as a function of torso flexion, and identify individual characteristics that are associated with the magnitude of the moment arms as a function of torso flexion. STUDY DESIGN/SETTING Utilization of a 0.3 Tesla Open magnetic resonance image (MRI) to image and quantify the moment arm of the right erector muscle group as a function of gender and torso flexion. METHODS Axial MRI images through and parallel to each of the lumbar intervertebral discs at four torso flexion angles were obtained from 12 male and 12 female subjects in a lateral recumbent posture. Multivariate analysis of variance was used to investigate the differences in the moment arms at different torso flexion angles, whereas hierarchical linear regression was used to investigate associations with individual anthropometric characteristics and spinal posture. RESULTS The largest decrease in the lumbar erector muscle group moment arm from neutral to 45-degree flexion occurred at the L5-S1 level (9.7% and 8.9% for men and women, respectively). Measures of spinal curvature (L1-S1 lordosis), body mass and trunk characteristics (depth or circumference) were associated with the varying moment arm at most lumbar levels. CONCLUSIONS The sagittal plane moment arms of the lumbar erector muscle mass decrease as the torso flexes forward. The change in moment arms as a function of torso flexion may have an impact on prediction of spinal loading in biomechanical models.
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Affiliation(s)
- Michael J Jorgensen
- Industrial and Manufacturing Engineering Department, Wichita State University, 120 Engineering Building, Wichita, KS 67260-0035, USA.
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van Dieën JH, Selen LPJ, Cholewicki J. Trunk muscle activation in low-back pain patients, an analysis of the literature. J Electromyogr Kinesiol 2003; 13:333-51. [PMID: 12832164 DOI: 10.1016/s1050-6411(03)00041-5] [Citation(s) in RCA: 405] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
This paper provides an analysis of the literature on trunk muscle recruitment in low-back pain patients. Two models proposed in the literature, the pain-spasm-pain model and the pain adaptation model, yield conflicting predictions on how low- back pain would affect trunk muscle recruitment in various activities. The two models are outlined and evidence for the two from neurophsysiological studies is reviewed. Subsequently, specific predictions with respect to changes in activation of the lumbar extensor musculature are derived from both models. These predictions are compared to the results from 30 clinical studies and three induced pain studies retrieved in a comprehensive literature search. Neither of the two models is unequivocally supported by the literature. These data and further data on timing of muscle activity and load sharing between muscles suggest an alternative model to explain the alterations of trunk muscle recruitment due to low-back pain. It is proposed that motor control changes in patients are functional in that they enhance spinal stability.
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Affiliation(s)
- Jaap H van Dieën
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Free University Amsterdam, Van der Boechorststraat 9, NL-1081 BT, Amsterdam, The Netherlands.
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van der Burg JCE, Kingma I, van Dieën JH. Effects of unexpected lateral mass placement on trunk loading in lifting. Spine (Phila Pa 1976) 2003; 28:764-70. [PMID: 12698118 DOI: 10.1097/01.brs.0000058936.18057.ec] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A repeated measurements experiment of spinal loading in healthy subjects. OBJECTIVES To test whether unexpected lateral mass placement increases low back loading and trunk movement when subjects are lifting a mass in upright posture. SUMMARY OF BACKGROUND DATA Epidemiologic studies suggest that sudden, unexpected loading will lead to low back pain. Also, asymmetric loading is considered to be harmful to the spine. It can be anticipated that unexpected asymmetric loading will increase the risk of injury even more. METHODS Ten subjects lifted in an upright posture a crate, in which a mass of 10 kg was placed laterally at the left side either expectedly or unexpectedly. The crate reaction forces, body movements, and trunk muscle activity were measured. From these, the L5-S1 net moments and muscle forces were estimated. RESULTS Unexpected lateral placement of the mass caused no clear increase in peak low back loading. The stiffness of the trunk was lower in the unexpected condition, which, in combination with inadequate net moments produced, resulted in movement of the trunk to the side of the displaced mass. CONCLUSIONS Unexpected lateral mass placement does not increase the compression force. Perturbed trunk movement and lower muscle forces indicated a decreased stability of the spine, which may imply an injury risk.
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Affiliation(s)
- J C E van der Burg
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
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van Dieën JH, Hoozemans MJM, van der Beek AJ, Mullender M. Precision of estimates of mean and peak spinal loads in lifting. J Biomech 2002; 35:979-82. [PMID: 12052401 DOI: 10.1016/s0021-9290(02)00051-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A bootstrap procedure was used to determine the statistical precision of estimates of mean and peak spinal loads during lifting as function of the numbers of subjects and measurements per subject included in a biomechanical study. Data were derived from an experiment in which 10 subjects performed 360 lifting trials each. The maximum values per lift of the lumbar flexion angle, L5S1 sagittal plane moment, and L5S1 compression force were determined. From the data set thus compiled, 3000 samples were randomly drawn for each combination of number of subjects and number of measurements considered. The coefficients of variation of mean and peak (defined as mean plus 2 standard deviations) spinal loads across these samples were calculated. The coefficients of variation of the means of the three parameters of spinal load decreased as a linear function of the number of subjects to a power of about -0.48 and number of measurements to a power of about -0.06, while the corresponding powers for peak loads were about -0.44 and -0.11.
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Affiliation(s)
- Jaap H van Dieën
- Faculty of Human Movement Science, Institute of Fundamental and Clinical Human Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 9, NL-1081 BT Amsterdam, The Netherlands.
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van Dieën JH, Dekkers JJ, Groen V, Toussaint HM, Meijer OG. Within-subject variability in low back load in a repetitively performed, mildly constrained lifting task. Spine (Phila Pa 1976) 2001; 26:1799-804. [PMID: 11493854 DOI: 10.1097/00007632-200108150-00016] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A repeated-measures in vivo experiment. OBJECTIVE To describe within-subject variability of spinal compression in repetitive lifting. SUMMARY OF BACKGROUND DATA Epidemiology and failure mechanics suggest that peak loads may be more predictive of injury than average loads. Nevertheless, biomechanical studies usually focus on the latter. METHODS Ten healthy males performed 360 lifts in 1 hour of a 45-L crate, weighted with a stable 10-kg mass on 1 day and with an unstable mass (10 kg of water) on another day. The maximum compression force in each lift was estimated, using a simple inverse dynamics model and a single equivalent muscle model. RESULTS The individual distributions of maximum compression force were slightly skewed to the right (average skewness 0.67). Median and 95th percentile values were used to characterize the distribution. The median (50th percentile) compression ranged from 3375 to 6125 N, and from 3632 to 6298 N in the stable and unstable load conditions, respectively. The within-subjects peak (95th percentile) compression forces were from 405 to 1767 N and from 526 to 2216 N, respectively, higher than the median values. The peak values differed significantly between conditions, whereas the difference in medians did not reach significance. Only a limited trendwise (fatigue-related) variance could be demonstrated. CONCLUSION Peak spinal compression by far exceeds median compression in repetitive lifting and can be affected by task conditions independently from the median. Therefore, the variability of spinal loads needs to be taken into consideration when analyzing and redesigning tasks that can cause spinal injuries.
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Affiliation(s)
- J H van Dieën
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
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van Dieën JH, Hoozemans MJ, Toussaint HM. Stoop or squat: a review of biomechanical studies on lifting technique. Clin Biomech (Bristol, Avon) 1999; 14:685-96. [PMID: 10545622 DOI: 10.1016/s0268-0033(99)00031-5] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To assess the biomechanical evidence in support of advocating the squat lifting technique as an administrative control to prevent low back pain. BACKGROUND Instruction with respect to lifting technique is commonly employed to prevent low back pain. The squat technique is the most widely advised lifting technique. Intervention studies failed to show health effects of this approach and consequently the rationale behind the advised lifting techniques has been questioned. METHODS Biomechanical studies comparing the stoop and squat technique were systematically reviewed. The dependent variables used in these studies and the methods by which these were measured or estimated were ranked for validity as indicators of low back load. RESULTS Spinal compression as indicated by intra-discal pressure and spinal shrinkage appeared not significantly different between both lifting techniques. Net moments and compression forces based on model estimates were found to be equal or somewhat higher in squat than in stoop lifting. Only when the load could be lifted from a position in between the feet did squat lifting cause lower net moments, although the studies reporting this finding had a marginal validity. Shear force and bending moments acting on the spine appeared lower in squat lifting. Net moments and compression forces during lifting reach magnitudes, that can probably cause injury, whereas shear forces and bending moments remained below injury threshold in both techniques. CONCLUSION The biomechanical literature does not provide support for advocating the squat technique as a means of preventing low back pain. RELEVANCE Training in lifting technique is widely used in primary and secondary prevention of low back pain, though health effects have not been proven. The present review assesses the biomechanical evidence supporting the most widely advocated lifting technique.
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Affiliation(s)
- J H van Dieën
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands. ,nl
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de Looze MP, Groen H, Horemans H, Kingma I, van Dieën JH. Abdominal muscles contribute in a minor way to peak spinal compression in lifting. J Biomech 1999; 32:655-62. [PMID: 10400352 DOI: 10.1016/s0021-9290(99)00061-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In lifting, the abdominal muscles are thought to be activated to stabilize the spine. As a detrimental effect, they contribute to spinal compression. The existing literature is not conclusive about the biological relevance of this effect. From biological, mechanical and anatomical considerations it was hypothesised that the relative abdominal contribution to compression would be minor in the beginning of the lift, that the relative and absolute abdominal contribution to compression would rise throughout the lift, and that the obliques would contribute to a larger extent than the rectus abdominis. To investigate these hypotheses, 10 subjects lifted 0.5, 10.5 and 22.5 kg. EMG levels obtained from the rectus abdominis and the obliques were converted into force using normalized EMG, muscle potential and area values, and modulating factors for muscle length and contraction velocity. An anatomical model was applied to compute the abdominal effects on spinal compression in three consecutive phases within a lift. If expressed relative to the total spinal compression, the abdominal contribution for the three weight conditions was 7.1% (SD, 1.7), 10.4% (4.7) and 12.5% (4.4) in the begin and 21.0% (5.8), 19.0% (5.3) and 22.2% (6.6) in the end phase. Thus, the relative abdominal contribution to compression was minor in the beginning and increased towards the end. The absolute abdominal contribution was constant throughout the lift. The contributions could be retraced to the obliques rather than the rectus, while during the lift a shift in activation from the obliquus externus to internus was observed.
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Affiliation(s)
- M P de Looze
- Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
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van Dieën JH, Kingma I. Total trunk muscle force and spinal compression are lower in asymmetric moments as compared to pure extension moments. J Biomech 1999; 32:681-7. [PMID: 10400355 DOI: 10.1016/s0021-9290(99)00044-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The aim of the present study was to test the assumption that asymmetric trunk loading requires a higher total muscle force and consequently entails a higher compression forces on the spine as compared to symmetric loading. When the trunk musculature is modelled in sufficient detail, optimisation shows that there is no mechanical necessity for an increase in total muscle force (or compression force) with task asymmetry. A physiologically based optimisation does also not predict an increase in total muscle force or spinal loading with asymmetry. EMG data on 14 trunk muscles collected in eight subjects showed antagonistic coactivity to be present in both conditions. However, estimates of total muscle force based on the EMG were lower when producing an asymmetric moment. In conclusion, producing an asymmetric moment appears to cause slightly lower forces on the lumbosacral joint as compared to a symmetric moment. Only lateral shear forces increase with asymmetry but these remain well below failure levels.
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Affiliation(s)
- J H van Dieën
- Amsterdam Spine Unit, Institute for Fundamental and Clinical Human Movement Sciences, The Netherlands.
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