Low Back Compression Research Articles

Lower Back & Comfortability Analysis of Driving Posture to Mitigate Musculoskeletal Disorders: An Ergonomics Study using Digital Human Modelling in JACK Software

In this paper, the crucial aspect of driver comfort was explored by investigating the prevailing driving postures among individuals, aiming to discern their ergonomic implications and ascertain whether the commonly adopted postures are conducive to musculoskeletal health or pose potential risks. From the last decade vehicle like cars have become one of the common modes of personal transport. Car has high relevance in day-to-day activities like commuting, economic activities and sports etc. The continuous driving of vehicle can lead the driver prone to musculoskeletal disorders such as back pain, spine injury and posture issues. This study is conducted to address the ergonomic aspects of posture of the driver to highlight the risk of Musculoskeletal disorders (MSDs) and to optimize the driving posture. Lower Back Analysis (LBA) and Comfortability Analysis is performed in JACK Software to analyze the driving posture. A DHM (Digital Human Model) is created in JACK Simulation Software according to the collected anthropometric data of an average Pakistani man. A virtual Environment is created in JACK Simulation Software. The posture of the subject is analyzed by taking measurements of the subject’s angle of joints when they are sitting in a driving posture. For Ergonomic Analysis the Driving Posture is evaluated on JACK software to Mitigate Musculoskeletal Disorders. Results show that the subject is having low back compression force of 672 which is below the NIOSH Back Compression Action Limit of 3400N representing a nominal risk of low back injury.

Increased Ability to Perceive Relevant Sensory Information Minimizes Low Back Exposures in Lifting.

We have previously shown evidence that some individuals seem to consistently minimize low back loads when lifting, while others do not. However, it is unknown why. Individual differences in ability to perceive relevant sensory information may explain differences in minimization of low back loads during lifting, consistent with considering load reduction in one's movement objective in an optimal feedback control theory framework. The purpose of this study was to investigate whether individuals' ability to perceive proprioceptive information (both force- and posture-senses) at the low back was associated with peak low back loads when performing generic or occupation-specific lifts. Seventy-two participants were recruited to perform 10 barbell (generic) and backboard (occupation-specific) lifts, while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear forces normalized to body mass were calculated as dependent variables. Both posture matching ability and force matching ability at the heavier force targets were associated with lower means and variability of peak low-back loads in both lift types, albeit with small effect sizes (R2 ≤ .17). These findings support the utility of an optimal feedback control theory framework to explore factors explaining interindividual differences in low back loads during lifting. Further, this evidence suggests improving proprioceptive ability may be a useful strategy in lift training programs designed for workplace injury prevention.

The Influence of Contextual and Theoretical Expertise on Generic and Occupation-Specific Lifting Strategy.

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. 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. 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. 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. 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. 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.

Ergonomic Risk Assessment and Fatigue Analysis During Manual Lifting Tasks in Farming Activities

Introduction: Farming is a physically demanding occupation that puts farmers at risk of musculoskeletal disorders, particularly when frequently performing activities like heavy lifting, which strains the lower back muscles. The present study aimed to assess the ergonomic risk and fatigue during manual lifting tasks pertaining to farming activities. Methods: A study was performed on 20 farmers to analyze the ergonomic risks associated with load lifting through the estimation of the Recommended Weight Limit and Lifting Index using the revised NIOSH lifting equation. The low back compression forces of the participants were estimated using the 3DSSPP software. Surface electromyography was employed to analyze the onset of muscle fatigue during the lifting activity. Results: The results of the study showed a 111.12% increase in the recommended weight limit, a 52.77% reduction in lifting index, and a 28.15% reduction in the low back compression forces for the redesigned lifting technique. The average low-back compression force for the redesigned technique was observed to be well below the back compression design limit of 770 lb. A reduction in the slope of the RMS voltage regression line by 60% and a reduction of 50.23% in the peak spectral power of the sEMG signal, accompanied by a shift in the peak spectral power towards higher frequency region indicated delayed onset of fatigue for the redesigned technique. Conclusion: The outcomes of the study indicated that the ergonomic redesign of the lifting task could significantly reduce the lifting index and alleviate the spinal compression forces well within the back-compression design limit. The redesign was also found to delay the onset of fatigue in the erector spinae muscles.

The influence of bed height as a percentage of participant height on low back forces when boosting a patient up in bed.

Repositioning patients is a frequent task for healthcare workers causing substantial stress to the low back. Patient handling methodologies that reduce low back load should be used. Some studies have observed the effect of bed height on back forces using a limited range of heights. This study details a wider range. The aim of this study was to discover an optimal bed height for reducing low back force when boosting a patient. 11 university students and local residents participated by completing a series of boosts with a 91.6 kg research assistant acting as dependent. The bed was adjusted 3% of participant height and 3 boosts were completed at each height which resulted in 8-10 different bed heights depending on the height of the participant. Motion and force data were collected to estimate low back forces via 3DSSPP. Pearson's R was performed to observe the correlation between caregiver height and low back forces. There were significant negative correlations between bed height and low back compression force at L4-L5 (r = -0.676, p = <0.001) and L5-S1 (r = -0.704, p = <0.001). There were no significant correlations with any shear forces. The highest bed height led to decreased low back compression forces regardless of participant height, but there was not a significant difference in shear forces. Thus, healthcare workers may experience less low back stress with the bed at a higher height. There may be a force tradeoff between the low back and other parts of the body that needs further exploration. Healthcare workers need to be made aware of the implications of adjusting the environment when performing patient handling tasks.

Robust estimation of lumbar joint forces in symmetric and asymmetric lifting tasks via large-scale electromyography-driven musculoskeletal models

Low back joint compression forces have been linked to the development of chronic back pain. Back-support exoskeletons controllers based on low back compression force estimates could potentially reduce the incidence of chronic pain. However, progress has been hampered by the lack of robust and accurate methods for compression force estimation. Electromyography (EMG)-driven musculoskeletal models have been proposed to estimate lumbar compression forces. Nonetheless, they commonly underrepresented trunk musculoskeletal geometries or activation–contraction dynamics, preventing validation across large sets of conditions. Here, we develop and validate a subject-specific large-scale (238 muscle–tendon units) EMG-driven musculoskeletal model for the estimation of lumbosacral moments and compression forces, under eight box-lifting conditions. Ten participants performed symmetric and asymmetric box liftings under 5 and 15 kg weight conditions. EMG-driven model-based estimates of L5/S1 flexion–extension moments displayed high correlation, R2 (mean range: 0.88–0.94), and root mean squared errors between 0.21 and 0.38 Nm/kg, with respect to reference inverse dynamics moments. Model-derived muscle forces were utilized to compute lumbosacral compression forces, which reached eight times participants body weight in 15 kg liftings. For conditions involving stooped postures, model-based analyses revealed a predominant decrease in peak lumbar EMG amplitude during the lowering phase of liftings, which did not translate into a decrease in muscle–tendon forces. During eccentric contraction (box-lowering), our model employed the muscle force–velocity relationship to preserve muscle force despite significant EMG reduction. Our modeling methodology can inherently account for EMG-to-force non-linearities across subjects and lifting conditions, a crucial requirement for robust real-time control of back-support exoskeletons.

Characterization of Musculoskeletal Injury Risk in Dungeness Crab Fishing

ABSTRACT Objectives: Commercial Dungeness crab fishermen’s manual crab pot handling activities can be done in harsh outdoor working environments at sea and can pose well-known physical risk factors associated with musculoskeletal injury including forceful exertion, repetition and awkward posture. The nonfatal injury rate in this fishing fleet is 3.4 per 1,000 full-time equivalent workers. Two-thirds of self-reported injuries in the fleet were musculoskeletal sprains and strains. To date, no objective biomechanical assessment of musculoskeletal disorder (MSD) risk has been conducted due to the challenging work environment. Methods: The aim of this study was to determine the feasibility of collecting objective biomechanical assessments (i.e., posture and repetition) using inertial measurement unit (IMU) sensors placed on the arms and torso of professional deckhands (n = 7) while at sea, harvesting Dungeness crab. Based on the IMU-measured posture data, fishermen’s anthropometry, and crab pot weights, biomechanical loading of the low back and both shoulders was estimated. Results: The IMU sensor data showed that commercial Dungeness crab fishing is highly repetitive and poses awkward postures in the shoulders and back. The estimated static low back compression, shear force, and flexion moment about the shoulders and low back (L5/S1) indicate potential injury risk associated with harvesting crab. Conclusion: The results indicate that objective biomechanical assessment using the IMU sensors is feasible in the commercial fishing environment.

A pilot study of biomechanical and ergonomic analyses of risky manual tasks in physical therapy

The objective of this pilot study was to identify risk factors in physical therapy by performing quantitative ergonomic postural and biomechanical analyses of representative manual tasks. A total of 23 physical therapy students were recruited to perform six patient handling and joint mobilization tasks. Movement data were collected by a motion capture system. Biomechanical and ergonomic analyses were performed, including estimate of lumbar spine compression force, Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA). It was found that the low back compression forces of different transfer tasks were greater than the safety threshold. The ergonomic analysis showed that the three transfer tasks had high risk and the mobilization tasks had low to medium risk. Changes should be implemented to modify these body postures.

Dynamic Work Analysis of Manual Material Handling With Digital Human Modeling

The activity of loading and unloading rice in Indonesia is still carried out using human power. Porters transport rice manually from truck to warehouse or the otherwise. Manual material handling work (MMH) will pose a risk of musculoskeletal disorders (MSDs). The application of the work analysis method generates an analysis per one body position only. There is a need for a model that can perform a work analysis quickly for any change in body movement if it is carried out in dynamic work, for instances on rice porters. In this research, Digital Human Modeling Tecnomatix Jack is used in the Task Simulation Builder menu to simulate dynamic work and generate analysis. The dynamic work carried out is to compare the risk of transporting rice weighing 10 kg and 25 kg. The results obtained are Ergonomic Report, Static Strength Prediction (SSP), Low Back Compression Analysis (LBA), Fatigue, Cumulative Loading and Metabolic Energy Expenditure (MEE). The simulator also provides the SSV file extension as in SSP. If needed, this result can be entered in a formula according to work analysis method such as RULA or REBA so that every change in movement obtained results related to the risk that may occur.

Comparing the biomechanical and perceived exertion imposed on workers when using manual mechanical and powered cargo management systems during ladder loading and unloading tasks

This study aimed to compare the effects of two different cargo management systems (one powered system, i.e., the RazerLift®, and one Traditional system) on the biomechanical and perceived exertion experienced by workers when performing routine ladder loading and unloading tasks. Seven experienced workers performed ladder loading and unloading tasks. Compared to when the Traditional system was being used, the cumulative static low-back compression force was reduced by 57.9% (p < 0.05) and 39.3% (p < 0.05) when the RazerLift® was being used to perform ladder loading and unloading tasks, respectively. Overall, the cumulative shoulder flexor moments were reduced by 34.8% (p < 0.05) and 41.3% (p < 0.05) when the RazerLift® was being used to perform ladder loading and unloading tasks, respectively. Overall, the perceived exertion score was reduced by 250.1% (p < 0.05) when the RazerLift® was being used compared to the Traditional system. In conclusion, our study demonstrated that the RazerLift® reduces the biomechanical and psychophysical exposure associated with the development of musculoskeletal disorders while performing ladder loading and unloading tasks.

Ergonomic Assessment of Low Back Loading Pattern During Occupational Lifting Task in a Lower Limb Amputee: Minimizing Injury Risk.

While the relationship between occupational task intensity and repetitive overuse injuries have been well studied and prescription/guidelines to assess and minimize risk of such injuries well established in the general healthy population, these aspects are not well understood in individuals with disabilities. In this practice-oriented paper, we use high a resolution sensor-data driven methodology to track muscle activation patterns and joint kinematics during a common lifting task in a unilateral lower limb amputee to gain a better understanding of the risk of injury during non-optimal lifting postures. The observed data from high resolution sensors are used to recommend optimized prosthetic device tuning. Further the participant specific low back compression loads calculated using Hand-Calculation Back Compressive Force estimation model (HCBCF) and the University of Michigan 3D Static Strength Prediction Program (3DSSPP™) model is used to identify the safe zones of joint loading during the lifting task.

Exploring the prospective efficacy of waste bag-body contact allowance to reduce biomechanical exposure in municipal waste collection

Municipal waste collectors must avoid bag-body contact, requiring waste bags to be held further from the body. Donning sharps-proof clothing would permit bag-body contact, allowing the bag to be closer to the body, reducing biomechanical exposures. To test this hypothesis, 25 participants loaded waste bags into a simulated garbage truck hopper under two lifting (contact allowed, no contact) and bag mass (7 kg and 20 kg) conditions. Bottom-up rigid-link biomechanical modelling results including peak low back compression force, antero-posterior shear force and peak low back flexion angle were not different between the lifting conditions, but cumulative compression was decreased with bag-body contact, although only at the 20 kg mass. Bag mass had significant effects on outcome measures, causing compression to increase to 4663 (±697) N, exceeding recommended thresholds. Sharps-proof clothing and municipally mandated 23 kg maximum allowable bag mass restrictions may not sufficiently reduce biomechanical exposures to prevent MSD.

Development and Validation of a Wearable Inertial Sensors-Based Automated System for Assessing Work-Related Musculoskeletal Disorders in the Workspace.

The industrial societies face difficulty applying traditional work-related musculoskeletal disorder (WMSD) risk assessment methods in practical applications due to in-situ task dynamics, complex data processing, and the need of ergonomics professionals. This study aims to develop and validate a wearable inertial sensors-based automated system for assessing WMSD risks in the workspace conveniently, in order to enhance workspace safety and improve workers’ health. Both postural ergonomic analysis (RULA/REBA) and two-dimensional static biomechanical analysis were automatized as two toolboxes in the proposed system to provide comprehensive WMSD risk assessment based on the kinematic data acquired from wearable inertial sensors. The effectiveness of the developed system was validated through a follow-up experiment among 20 young subjects when performing representative tasks in the heavy industry. The RULA/REBA scores derived from our system achieved high consistency with experts’ ratings (intraclass correlation coefficient ≥0.83, classification accuracy >88%), and good agreement was also found between low-back compression force from the developed system and the reference system (mean intersystem coefficient of multiple correlation >0.89 and relative error <9.5%). These findings suggested that the wearable inertial sensors-based automated system could be effectively used for WMSD risk assessment of workers when performing tasks in the workspace.

Evaluation in design of walker trainer for spatial ataxic athetoid cerebral palsy children using kinect sensor as observation method for assessing body posture on walking

Balance is a general term that explains the dynamism of body posture to prevent someone from falling. During the child’s growth sensory and motor disorders can be happen that reduce the ability to walk. Celebration Palsy (CP) is a type of disability that attacks child motor disorders. The main objective of this study is to evaluate the body balance of the CP child when using a walker trainer to assess body posture using the REBA method. The test running when the CP child is walking using a walker trainer, then a picture of the child’s posture will be taken using the Kinect Sensor Microsoft XBOX One. Then do posture analysis using the REBA method and 3DSSPP software to find out the comparison results before and after using a walker trainer. The result from REBA score when using an old walker give a score of 9 with a level of risk in musculoskeletal risk, while REBA score when using a new walker give a score of 5. Low back compression result from 3DSSP software when using old walker is 807.7 lb and when using a new walker of 531.8 lb. this result can be accepted by respondents and within safe limits.

Ranking Stretcher and Backboard Related Paramedic Lifting Tasks Based on Their Biomechanical Demand on the Low Back

Occupational ApplicationsWe rank ordered essential paramedic lifting tasks by biomechanical exposure measures at the low back, to understand aspects of paramedic work that impose the greatest risk of musculoskeletal disorders. Specifically, stretcher raising, lowering, and loading, and scoop stretcher lifting, were ordered in terms of peak sagittal low back angles, peak low back compression and antero-posterior shear forces, estimated cumulative damage over a work shift, and the probability of being a high-risk work task. We found that scoop stretcher lifting imposed the highest peak low back angles and both compression and shear forces, while stretcher raising had the greatest estimated cumulative damage and probability of being a high-risk task. All tasks resulted in peak low back compression forces that exceeded injury risk guidelines, and all tasks were identified as high-risk based on estimated cumulative damage. These results highlight the need for interventions in the paramedic sector to reduce the resultant biomechanical exposures, prioritizing efforts towards scoop board lifting and stretcher raising.

The incorporation of virtual ergonomics to improve the occupational safety condition in a factory

Proper manual material handling (MMH) is the important step leading to the occupational safety of the workers on the shop floor as well as the productivity improvement of the manufacturing process. The objectives of this study are the application of different risk assessment methods, the redesign of the workstation to reduce the occupational risk and the utilization of software package to validate the proposed interventions. As a result, an assembly line of a product is selected as the case study to validate the proposed agenda. Afterwards, four lifting assessment methods, i.e. NIOSH lift equation, Snook Psychophysical Table, OSU Lift guidelines and ACGIH/TLV, are used to assess the hazard risk in the assembly line. After these methods are performed, the results are introduced to recommend the newly designed working conditions, i.e. postures, movements and the barriers. To validate the improved design, new configurations are simulated by the virtual ergonomic program and the ergonomic analysis is performed. The important results, e.g. low back compression and percent of population capable, are calculated by the software to determine the appropriate values which are used as the guidelines for a safe working condition. Moreover, the manufacturing process is also simulated to improve that the ergonomic redesign of the shop floor environment and another consequence of the implementation leads to the significant increase of the productivity.

Effect of pelvic forward tilt on low back compressive and shear forces during a manual lifting task.

[Purpose] To examine the effect of an instruction to increase pelvic forward tilt on low back load during a manual lifting task in the squat and stoop postures. [Subjects] Ten healthy males who provided informed consent were the subjects. [Methods] Kinetic and kinematic data were captured using a 3-dimensional motion analysis system and force plates. Low back compressive and shear forces were chosen as indicators of low back load. The subjects lifted an object that weighed 11.3 kg, under the following 4 conditions: squat posture, stoop posture, and these lifting postures along with an instruction to increase pelvic forward tilt. [Results] In the squat posture, the instruction to increase pelvic forward tilt reduced the low back compression and shear forces. [Conclusion] The present results suggest that a manual lifting task in the squat posture in combination with an instruction to increase pelvic forward tilt can decrease low back compression and shear forces, and therefore, might be an effective preventive method for low back pain in work settings.

Pilot Quality Improvement Study of SafeBack

Caregivers, including nurses, personal support workers, and family caregivers, have a high risk of low back pain due to the patient-handling postures they use. Often, caregivers place the needs of the care recipient above their own. This means that caregivers may use postures that put them at risk of injury. Often times, these caregivers may not even be aware of the potential for injury due to their posture selection. Therefore, there is a need for easy-to-use, inexpensive, and accessible education and training tools that can be used to guide the use of safer patient-handling postures. To address this need, we have developed SafeBack: a mobile application for estimating low back forces in either real-time or from photographs taken of the postures in need of evaluation. The app requires user- posturing of skeleton, and the input of anthropometric and load data before low back compression forces can be estimated. The purpose of this study was to run a pilot quality improvement study to gather user feedback about the SafeBack App. The results show that the App, in its current form, has acceptable usability, but that improvements are needed before it can be used as a post ure training and/or injury prevention tool.

Prevalence of occupation-related pain among baristas and an examination of low back and shoulder demand during the preparation of espresso-based beverages

Many baristas complain of low back pain (LBP) and upper extremity discomfort while at work. This study documented the prevalence of LBP and shoulder pain, via questionnaire, among a population of baristas to determine whether cumulative low back loads and shoulder moments are associated with pain reporting. Fifty-nine baristas completed the questionnaire; ten were also video-recorded for biomechanical analysis while making espresso beverages and cumulative and peak low back loads and shoulder moments were calculated. Seventy-three percent of those who completed the questionnaire reported having experienced LBP, and half attributed this pain to their job as a barista. Furthermore, 68% reported having experienced shoulder pain and half also attributed this pain to their job. Those who suffered from LBP had higher peak low back compression and those with shoulder pain had, in general, higher moments about their dominant shoulder.

1B2-1 持ち上げ動作によって生じる椎間板圧縮力の比較

1B2-1 持ち上げ動作によって生じる椎間板圧縮力の比較