Co-Contraction Recruitment and Spinal Load during Isometric Pushing Tasks

2005 ◽  
Vol 49 (14) ◽  
pp. 1330-1333 ◽  
Author(s):  
Kevin Granata ◽  
Patrick Lee ◽  
Tim Franklin
Keyword(s):  
Biomechanical Model ◽  
Neuromuscular Control ◽  
Surface Emg ◽  
Trunk Flexion ◽  
Materials Handling ◽  
Manual Materials Handling ◽  
Muscle Groups ◽  
Spinal Load ◽  
Theoretical Analyses ◽  
Flexion And Extension

Pushing and pulling tasks account for 20% of occupational low-back injury claims but few studies have investigated the neuromuscular control of the spine during these tasks. Primary torso muscle groups recruited during pushing tasks include the rectus abdominis and external obliques. However, theoretical analyses suggest that co-contraction of the paraspinal muscles is necessary to stabilize the spine during flexion exertions. A biomechanical model was implemented to estimate co-contraction and spinal load from measured surface EMG and trunk moment data recorded during trunk flexion and extension exertions. Results demonstrate that co-contraction during flexion exertions was approximately twice the value of co-contraction during extension. Co-contraction accounted for up to 47% of the total spinal load during flexion exertions and spinal load attributed to co-contraction was nearly 50% greater during flexion than during extension exertions despite similar levels of trunk moment. Results underscore the need to consider neuromuscular recruitment when evaluating biomechanical risks. Keywords: Spine; Co-contraction; Push; Manual Materials Handling; Biomechanics

Neuromuscular Control and Active Trunk Stiffness during Isometric Flexion and Extension

2005 ◽  
Vol 49 (14) ◽  
pp. 1334-1338
Author(s):  
Kevin Granata ◽  
Patrick Lee
Keyword(s):  
Neuromuscular Control ◽  
Random Force ◽  
Muscle Stiffness ◽  
Spinal Stability ◽  
Trunk Flexion ◽  
Trunk Motion ◽  
Materials Handling ◽  
Motion Data ◽  
Trunk Movements ◽  
Flexion And Extension

Pushing and pulling tasks account for 20% of low-back injury claims. Torso flexion necessary for pushing exertions requires different muscle recruitment than for extension exertions typical of lifting tasks. These differences in recruitment and control may influence spinal stability and associated risk of injury. Active muscle stiffness is considered the primary stabilizing mechanism for spinal stability. Therefore, active trunk stiffness was recorded while subjects generated upright isometric trunk flexion and extension exertions against an isotonic preload. Small pseudo-random force disturbances were superimposed on the preloads causing small amplitude trunk movements. Trunk stiffness was computed from systems identification of the measured force and trunk motion data. Results demonstrated significantly greater stiffness during flexion exertions as compared to extension exertions. EMG data suggest this difference was due to increased co-contraction during the flexion exertions. These behaviours were attributed to the need to augment neuromuscular control of spinal stability during pushing tasks. Keywords: Spine; Co-contraction; Push; Manual Materials Handling; Biomechanics

Quantifying the Precision of Biomechanical Calculations using Experimental Data

1987 ◽  
Vol 31 (3) ◽  
pp. 315-317
Author(s):  
M. Tracy ◽  
E.N. Corlett
Keyword(s):  
Standard Deviation ◽  
Biomechanical Model ◽  
Abdominal Pressure ◽  
Low Back ◽  
Mean Values ◽  
Materials Handling ◽  
Optical Scanner ◽  
Number Of Factors ◽  
Manual Materials Handling ◽  
On Line

Biomechanical calculations are a useful tool to evaluate the severity of manual materials handling tasks. The exactness of the calculated forces depends on a number of factors. On one level is the precision of the inputs such as postural data and the force exerted by the operator. At another level is the exactitude of the biomechanical model itself. The effect of the imprecision of each factor upon the final result can be calculated so that on one hand, the range of values within which the final result is likely to fall is known, and on the other hand, the importance of each factor can be assessed, by comparing the standard deviation of one or more factors with the standard deviation of the result. Calculations of forces on the low back have been carried out in the laboratory using an optical scanner (CODA-3) to record posture on-line to a computer, as well as a handle equipped with strain gauges to record the force exerted. The program automatically carries out biomechanical calculations from these inputs. It takes into account the uncertainties on muscle lever arms and intra-abdominal pressure, using mean values for these and estimating the confidence limits within which the calculated low-back forces will lie, given the variance of one or more of the inputs.

Comparison of Spinal Loads in Kneeling and Standing Postures during Manual Materials Handling

2005 ◽  
Vol 49 (14) ◽  
pp. 1320-1324
Author(s):  
Gang Yang ◽  
Riley Splittstoesser ◽  
Gregory Knapik ◽  
David Trippany ◽  
Sahika Vatan Korkmaz ◽  
...  
Keyword(s):  
Biomechanical Model ◽  
Job Design ◽  
Low Back ◽  
Spinal Loading ◽  
Materials Handling ◽  
Spinal Loads ◽  
Increased Risk ◽  
Manual Materials Handling ◽  
Free Dynamic ◽  
Anterior Posterior

Kneeling in a restricted posture during manual materials handling has been associated with increased risk of low back pain. Little is known about the effect of kneeling posture on spinal loads. The purpose of this study was to compare differences in spinal loading between kneeling and standing postures for lifting tasks. Twelve subjects asymmetrically lifted luggage of three weights to three heights from floor while kneeling. Three subjects also performed the same tasks from waist height while standing. An adapted free-dynamic EMG-assisted biomechanical model was used to calculate spinal loads. Statistical analysis showed that there was no difference in compression between kneeling and standing (p=0.9605), but kneeling resulted in increased anterior-posterior and lateral shear forces on the lumbar spine (p =0.0002 and p<0.0001, respectively). Spinal loading changes while kneeling in a restricted posture may increase the risk of low back injury and must be considered in ergonomic job design.

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.

scholarly journals Co-contraction recruitment and spinal load during isometric trunk flexion and extension

2005 ◽  
Vol 20 (10) ◽  
pp. 1029-1037 ◽  
Author(s):  
Kevin P. Granata ◽  
Patrick E. Lee ◽  
Timothy C. Franklin
Keyword(s):  
Trunk Flexion ◽  
Spinal Load ◽  
Flexion And Extension

Survey of One-handed Lifting in Manufacturing Industry: A Cross-sectional Study of the BackWorks Study Cohort

2020 ◽  
Vol 64 (1) ◽  
pp. 942-946
Author(s):  
Ruoliang Tang ◽  
Jay M. Kapellusch ◽  
Andrew S. Merryweather ◽  
Matthew S. Thiese ◽  
Kurt T. Hegmann ◽  
...  
Keyword(s):  
Manufacturing Industry ◽  
Cross Sectional Study ◽  
Study Cohort ◽  
The European Union ◽  
Sectional Study ◽  
Cross Sectional ◽  
Materials Handling ◽  
Manual Materials Handling ◽  
Lost Productivity ◽  
The One

Low back pain (LBP) is a common health problem and a major cause of lost productivity in workplaces. Manual materials handling (MMH) jobs have traditionally been regarded as risk factor for LBP. Compared to two-handed lifting, one-handed lifting has received little attention in both epidemiological and biomechanical research. In addition, one frequent complaint of the revised NIOSH lifting equation (RNLE) has been the lack of capability to directly evaluate one-handed lifting. Modifications have been proposed by the European Union, however their efficacy and influence have not yet been evaluated. This cross-sectional study provided objective survey of the MMH jobs, especially the one-handed lifting performed in manufacturing industry and investigated the outcomes of three proposed methods to address one-handed lifting using RNLE approach. Preliminary results suggest that workers with some one-handed lifting are associated with higher physical exposure. However, the increase was more significant among those who perform primarily one-handed lifting.

Detection of effort maximality in adults performing isokinetic wrist flexion and extension

2021 ◽  
pp. 1-7
Author(s):  
Mercè Torra ◽  
Eduard Pujol ◽  
Anna Maiques ◽  
Salvador Quintana ◽  
Roser Garreta ◽  
...  
Keyword(s):  
High Velocity ◽  
Healthy Male ◽  
Wrist Flexion ◽  
Low Velocity ◽  
Wrist Extensor ◽  
Submaximal Effort ◽  
The Difference ◽  
Muscle Groups ◽  
Maximal Effort ◽  
Flexion And Extension

BACKGROUND: The difference between isokinetic eccentric to concentric strength ratios at high and low velocities (DEC) is a powerful tool for identifying submaximal effort in other muscle groups but its efficiency in terms of the wrist extensors (WE) and flexors (WF) isokinetic effort has hitherto not been studied. OBJECTIVE: The objective of the present study is to examine the usefulness of the DEC for identifying suboptimal wrist extensor and flexor isokinetic efforts. METHODS: Twenty healthy male volunteers aged 20–40 years (28.5 ± 3.2) were recruited. Participants were instructed to exert maximal and feigned efforts, using a range of motion of 20∘ in concentric (C) and eccentric (E) WE and WF modes at two velocities: 10 and 40∘/s. E/C ratios (E/CR) where then calculated and finally DEC by subtracting low velocity E/CR from high velocity ones. RESULTS: Feigned maximal effort DEC values were significantly higher than their maximal effort counterparts, both for WF and WE. For both actions, a DEC cutoff level to detect submaximal effort could be defined. The sensitivity of the DEC was 71.43% and 62.5% for WE ad WF respectively. The specificity was 100% in both cases. CONCLUSION: The DEC may be a valuable parameter for detecting feigned maximal WF and WE isokinetic effort in healthy adults.

scholarly journals Trunk Posture during Manual Materials Handling of Beer Kegs

2021 ◽  
Vol 18 (14) ◽  
pp. 7380
Author(s):  
Colleen Brents ◽  
Molly Hischke ◽  
Raoul Reiser ◽  
John Rosecrance
Keyword(s):  
Small Businesses ◽  
Inertial Measurement Unit ◽  
Measurement Unit ◽  
Low Back ◽  
Inertial Measurement ◽  
Materials Handling ◽  
Kinematic Measurement ◽  
Manual Materials Handling ◽  
Trunk Posture ◽  
Data Design

Craft brewing is a rapidly growing industry in the U.S. Most craft breweries are small businesses with few resources for robotic or other mechanical-assisted equipment, requiring work to be performed manually by employees. Craft brewery workers frequently handle stainless steel half-barrel kegs, which weigh between 13.5 kg (29.7 lbs.) empty and 72.8 kg (161.5 lbs.) full. Moving kegs may be associated with low back pain and even injury. In the present study, researchers performed a quantitative assessment of trunk postures using an inertial measurement unit (IMU)-based kinematic measurement system while workers lifted kegs at a craft brewery. Results of this field-based study indicated that during keg handling, craft brewery workers exhibited awkward and non-neutral trunk postures. Based on the results of the posture data, design recommendations were identified to reduce the hazardous exposure for musculoskeletal disorders among craft brewery workers.

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