Three Dimensional Measures of Trunk Motion Components during Manual Materials Handling in Industry

1989 ◽  
Vol 33 (11) ◽  
pp. 662-666 ◽  
Author(s):  
W.S. Marras ◽  
L.R. Sudhakar ◽  
S.A. Lavender
Keyword(s):  
Three Dimensional ◽  
Work Place ◽  
Trunk Motion ◽  
Materials Handling ◽  
Health History ◽  
Manual Materials Handling ◽  
Back Disorder ◽  
Spine Motion ◽  
Motion Characteristics ◽  
The Relationship

The objective of this study was to monitor and document the three dimensional spine motion components experienced during the performance of industrial work that is associated with various risks of low back disorder (LBD). An industrial study was performed that examined on-the-job trunk motions of 64 workers from 13 different industries. Trunk range of motion, velocity and acceleration were documented. Worker anthropometry, health history, external load moments, job satisfaction and risk (identified from OSHA 200 logs) were also recorded for the various jobs. The results identified and quantified those trunk motion characteristics as well as other workplace variables that were associated with high risk jobs. A regression model of job related LBD risk was also created based upon this information. The relationship between these motions and biomechanical loading of the spine as well as means to reduce the risk of LBD in the work place (based upon this study) are discussed.

Industrial Quantification of Occupationally-Related Low Back Disorder Risk Factors

1992 ◽  
Vol 36 (10) ◽  
pp. 757-760 ◽  
Author(s):  
William S. Marras ◽  
Steven A. Lavender ◽  
Sue E. Leurgans ◽  
Sudhakar L. Rajulu ◽  
W. Gary Allread ◽  
...  
Keyword(s):  
High Risk ◽  
Three Dimensional ◽  
Objective Measure ◽  
Low Risk ◽  
Low Back ◽  
Lateral Velocity ◽  
Trunk Motion ◽  
Materials Handling ◽  
Back Disorder

Few assessment technigues have attempted to define the role of occupational trunk motion in the risk of occupationally-related low back disorder (LBD) even though laboratory studies have indicated that motion significantly Increases spine loading. An in-vivo study was performed to assess the contribution of three- dimensional dynamic trunk motions to the risk of LBD during occupational lifting in industry. Over 400 industrial lifting jobs were studied in 48 industries. Specific manual materials handling jobs historically identify as either high risk or low risk for LBD were identified. A tri-axial electrogoniometer was worn by workers and documented the three-dimensional trunk motion characteristics associated with these high risk or low risk jobs. Workplace characteristics such as load moment arm, load weight, etc. were also documented for each of the repetitive lifting tasks. A multiple logistic regression model indicated that a combination of five trunk motion and workplace factors (lifting frequency, load moment, trunk lateral velocity, trunk twisting velocity, and trunk sagittal angle) predicted occupational-related LBD risk well. The analyses have enabled us to determine the LBD risk associated with combined changes in the magnitudes of the five factors. This model could be used as a quantitative, objective measure to redesign the workplace so that the risk of occupationally-related LBD is minimized.

The Relationship between Occupational Musculoskeletal Discomfort and Workplace, Personal, and Trunk Kinematic Factors

1998 ◽  
Vol 42 (12) ◽  
pp. 896-900 ◽  
Author(s):  
W. Gary Allread ◽  
William S. Marras ◽  
Fadi A. Fathallah
Keyword(s):  
Physical Parameters ◽  
Low Back ◽  
Body Parts ◽  
Personal Factors ◽  
Musculoskeletal Discomfort ◽  
Materials Handling ◽  
Manual Materials Handling ◽  
Workplace Factors ◽  
Manufacturing Environments ◽  
The Relationship

Little research exists that quantifies joint kinematics and associated musculoskeletal discomfort. Therefore, the main objective of this study was to investigate the relationship between musculoskeletal discomfort and trunk kinematic factors, workplace factors, and personal factors of those performing manual materials handling jobs in manufacturing environments. An industrial database of 337 subjects was used in this study. The results showed that the prevalence of reported low-back discomfort was 36.5%. The findings suggested that both workplace factors and kinematics were related to an employee's reported discomfort. Generally, physical parameters were associated with overall discomfort (‘No’ or ‘Yes’), whereas trunk kinematics seem to be associated with discomfort of specific body parts. The magnitudes of these associations were not large, implying that multifactorial models that include other factors, such as psychosocial indicators, in addition to those studied here, may further explain discomfort reporting.

Trunk Strength during Asymmetric Trunk Motion

1989 ◽  
Vol 31 (6) ◽  
pp. 667-677 ◽  
Author(s):  
William S. Marras ◽  
Garya Mirka
Keyword(s):  
Work Environment ◽  
Common Finding ◽  
Low Back ◽  
Lumbosacral Junction ◽  
Trunk Motion ◽  
Materials Handling ◽  
Manual Materials Handling ◽  
The Common ◽  
Increased Strength ◽  
Trunk Strength

It is important to understand how trunk strength varies as a function of workplace factors so that the work environment can be designed to minimize the risk of low back injury. In this study maximal trunk torque production around the lumbosacral junction was measured in 44 subjects as trunk concentric and eccentric isokinetic velocity and trunk asymmetric line of action were varied. Trunk torque decreased by approximately 8.5% of maximum for every 15 deg of asymmetric trunk angle. Increases in concentric velocity decreased trunk strength, whereas increases in eccentric trunk velocity increased strength. Significant interactions were also found, and it was determined that the common finding that eccentric strength exceeds concentric strength is true only for forward trunk angles at all asymmetric angles. These results should have significant implications for the design of manual materials handling tasks.

Muscle Strength Simulations Using the Articulated Total Body Model

1986 ◽  
Vol 30 (1) ◽  
pp. 86-89 ◽  
Author(s):  
Andris Freivalds ◽  
Eui S. Jung ◽  
Randall Dick
Keyword(s):  
Three Dimensional ◽  
Biomechanical Model ◽  
Motor Units ◽  
State Function ◽  
Automobile Crashes ◽  
Materials Handling ◽  
Manual Materials Handling ◽  
Body Dynamics ◽  
Squat Lifting ◽  
Total Body

Further developments are presented on a dynamic three–dimensional strength model that may be useful for evaluating musculoskeletal stresses incurred during manual materials handling tasks. The model being developed is a modification of the Articulated Total Body (ATB) Model originally developed by Calspan Corp. for the study of human body dynamics during automobile crashes. Refinements were introduced by Freivalds and Kaleps (1984) to account for a human neuromusculature. Further refinements now include orderly recruitment patterns, differential motor units, active state function and fatigue. Simulations of squat lifting and level running were performed with the ATB Model. Both of these cases indicate the potential of a muscularized three–dimensional biomechanical model to simulate human responses in a variety of conditions.

Accuracy of a three-dimensional lumbar motion monitor for recording dynamic trunk motion characteristics

1992 ◽  
Vol 9 (1) ◽  
pp. 75-87 ◽  
Author(s):  
W.S. Marras ◽  
F.A. Fathallah ◽  
R.J. Miller ◽  
S.W. Davis ◽  
G.A. Mirka
Keyword(s):  
Three Dimensional ◽  
Trunk Motion ◽  
Motion Characteristics ◽  
Lumbar Motion

Dynamics of Trunk Performance during One-Handed Lifting

1993 ◽  
Vol 37 (10) ◽  
pp. 659-663 ◽  
Author(s):  
W. Gary Allread
Keyword(s):  
Perceived Exertion ◽  
Sagittal Plane ◽  
Force Plate ◽  
The Body ◽  
Rating Of Perceived Exertion ◽  
Low Back ◽  
Materials Handling ◽  
Back Disorder ◽  
Acceleration And Deceleration ◽  
Spine Motion

This study investigated the biomechanical effects of using one hand to perform a materials handling task. Subjects were asked to lift a box from a lower to an upper platform using either one or two hands. Three weight levels and four lower platform positions were examined. Subjects wore a back monitor (from which was calculated motion components in the three cardinal planes of the body), stood on a force plate, and were asked to give a rating of perceived exertion for each lift. Results of this study showed that one-handed lifts produced significantly higher ranges of lumbar spine motion in the lateral and transverse planes and greater flexion in the sagittal plane. Back motion risk factors previously found to be associated with high risk of injury jobs all were significantly higher for one-handed lifts. Two-handed lifts, however, produced overall faster motions in the sagittal plane, and equal or larger acceleration and deceleration magnitudes in all planes of motion. Results from the psychophysical measure found no differences in perceived exertion between one- and two-handed lifts. These results suggest that one-handed lifts load the spine more than two-handed lifts due to the added coupling and increase one's risk of suffering a low back disorder. This study also agrees with previous research finding that increased load weight and lifting from asymmetric positions increase risk of low back injury.

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