Effect of foot movement and an elastic lumbar back support on spinal loading during free-dynamic symmetric and asymmetric lifting exertions (original) (raw)
Related papers
Evaluation of spinal loading during lowering and lifting
Clinical Biomechanics, 1998
Objective. To estimate the three-dimensional spinal loads during various lifting and lowering tasks. Design. The in viva measurements of the trunk dynamics, moments, and myoelectric activity were used as inputs into an electromyographic-assisted model used to predict the three-dimensional spinal loads. Background. Previous studies of eccentric motions have investigated muscle activity, trunk strength, and trunk moments. A void in the body of knowledge exists in that none of these studies investigated spinal loading. Methods. Ten subjects lifted (40" of flexion to 00) and lowered (0" of flexion to 40") boxes while positioned in a structure that restrained the pelvis and hips. The tasks were performed under isokinetic trunk velocities of 5, 10, 20, 40, and 80 deg s-l while holding a box with weights of 9.1, 18.2, and 27.3 kg. Results. Lowering strength was found to be 56% greater than lifting strength. The lowering tasks produced significantly higher compression forces but lower anterior-posterior shear Forces than the lifting tasks. The differences in the spinal loads produced by the two lifting tasks were attributed to differences in coactivity and unequal lifting moments (i.e. holding the box farther away from the body). Conclusions. The nature of the spinal loads that occur during lowering and lifting were significantly different. The difference in spinal loads may be explained by different lifting styles. Relevance This study revealed the importance of investigating lowering as well as lifting since these types of motions result in drastically different EMG-torque relationships and, ultimately, different spinal loading patterns. Furthermore, this study indicates the importance of taking into account differences in lifting style (trunk moments) and the coactivity of the trunk muscles when estimating loads on the spine.
Safety and Health at Work, 2020
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2020
Abstract-Low-back pain and injury are responsible for a major portion of lost workdays and injury compensation claims. The use of back support belts has been forwarded as a counter measure towards reducing low-back injuries in the industrial setting. PURPOSE: The purpose of this study was to determine if a back support belt relieves stresses encountered by the lumbar spine during stoop type lifting and potentially reduce the risk of injury. METHODS: Twelve male participants (49.7±3.7 years) performed two sessions of stooped type lifting with a loaded milk crate (11.5 kg), at 4 repetitions per minute, for 15 minutes in accordance with the NIOSH lifting equation. One lifting session was performed without a support belt, while the other with a support belt. Three sets of fluoroscopic images were collected with the participants positioned at the initiation (flexed trunk), mid-range, and completion of the lift (erect standing). The first series of images were collected under a noload con...
Comparison of spinal loads in kneeling and standing postures during manual materials handling
PsycEXTRA Dataset
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 freedynamic 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.
Loads on the lumbar spine during a work capacity assessment test
Work, 2004
Many clinicians and employers utilise work-related assessment tools for the purposes of identifying whether or not the performance of a specific job exposes an individual to a heightened risk of developing a low back injury. However, research has shown that some of these tools have not been assessed for validity or reliability, and thus may not accurately assess the risk associated with a particular activity. An example of a test employed by some Australian private industries is the Work Capacity Assessment Test, which is a procedure that is commonly used to screen potential employees and evaluate those workers returning to the workplace following injury. This research was designed to simulate the lifting component of the Work Capacity Assessment Test and involved a series of lifts ranging from 2.5 kg to 22.5 kg. Six subjects performed this task, whilst being assessed using two-dimensional videography and surface electromyography. The two-dimensional kinematic data were input into the 4D WATBAK software to quantify the compression forces acting between L4 and L5 during each performance. Results of this study showed that spinal compression and paraspinal muscle activity increased incrementally from the 2.5 kg lift to the 22.5 kg lift, whilst abdominal muscle activity also increased across the lifts. This study demonstrated that lifting masses of 22.5 kg or more can produce loads on the spine that are considered potentially hazardous, when compared to safe lifting guidelines, and indicated that there is a clear concern for the use of such lifting tasks in the evaluation of workers following injury.
Applied Ergonomics, 2001
Back injuries are a serious problem for nursing personnel who perform frequent patient-handling activities. Common prevention strategies include body mechanics education, technique training, and ergonomic interventions such as the introduction of assistive equipment. This investigation assessed and compared the e!ectiveness of two patient-handling approaches to reducing injury risk. One strategy involved using improved patient-handling technique with existing equipment, and the other approach aimed at eliminating manual patient handling through the use of additional mechanical and other assistive equipment. Both intervention arms received training in back care, patient assessment, and use of the equipment available on their particular wards. An analysis of compliance with interventions and the e!ects of patient-handling methods on both peak and cumulative spinal compression and shear during various tasks was conducted. Results showed greater compliance with interventions that incorporated new assistive patient-handling equipment, as opposed to those consisting of education and technique training alone. In several tasks, subjects who were untrained or non-compliant with interventions experienced signi"cantly higher peak spinal loading. However, patient-handling tasks conducted with the aid of assistive equipment took substantially longer than those performed manually. This, along with variations in techniques, led to increases in cumulative spinal loading with the use of patient-handling equipment on some tasks. Thus, the use of mechanical assistive devices may not always be the best approach to reducing back injuries in all situations. No single intervention can be recommended; instead all patient-handling tasks should be examined separately to determine which methods maximize reductions in both peak and cumulative lumbar forces during a manoeuver.
Spine loading in patients with low back pain during asymmetric lifting exertions
The Spine Journal, 2004
BACKGROUND CONTEXT: Recurrent low back pain (LBP) is a common and costly problem that might be related to increased spine loads in those with LBP. However, we know little about how the spine is loaded when those with LBP perform lifting exertions. PURPOSE: Document spine loading patterns of patients with LBP performing symmetric and asymmetric lifting exertions compared with asymptomatic individuals performing the same tasks. STUDY DESIGN: Spine loadings during lifting exertions that varied in asymmetric origin as well as horizontal and vertical distance from the spine were compared between asymptomatic subjects and patients with LBP. METHODS: Sixty-two patients with LBP and 61 asymptomatic individuals performed a variety of lifting exertions that varied in lift origin horizontal and vertical position (region), lift asymmetry position and weight lifted. An electromyography-assisted model was used to evaluate spine loading in each subject during the lifting exertions. Differences in spine loading between the LBP and asymptomatic subjects were noted as a function of the experimental variables. RESULTS: Patients with LBP experienced greater spine compression and shear forces when performing lifting tasks compared with asymptomatic individuals. The least taxing conditions resulted in some of the greatest differences between LBP and asymptomatic individuals. CONCLUSIONS: Greater levels of antagonistic muscle coactivation resulted in increases in spine loading for patients with LBP. Specific lifting conditions that tend to exacerbate loading can be identified by means of physical workplace requirements. These findings may impact acceptable return-to-work conditions for those with LBP.
International Journal of Industrial Ergonomics, 1998
The experiment reported in this paper evaluated changes in lifting posture, static lifting strength and the estimated L3/L4 spinal compressive force resulting from the use of an abdominal support or 'back' belt. Torso posture and maximum static lift strength were measured for eight male and eight female subjects using symmetric and asymmetric hand positions at calf height and elbow height. Body posture, and hand forces were also used as input to a threedimensional static biomechanical model of the torso used to estimate L3/L4 spinal compressive force. The results showed axial twist of the torso to be significantly lower for calf height asymmetric exertions when the abdominal support belt was worn. The measured reduction in axial twist was approximately four degrees. No other significant effects on posture due to the support belt were found. Static lift strength was not significantly increased or reduced when the support belt was used. Predicted spinal compressive force was significantly lower when a support belt was worn (2840 N compared to 3125 N when the belt was not worn). Overall, the results of the experiment demonstrate a very limited benefit to the user of abdominal support belts, primarily due to reduced or restricted motion during asymmetric and lower-level lifts. Relevance to industry Back belts are commonly used in industry to mitigate manual materials handling hazards. One assumption often made by those recommending the use of back belts is that they substantially reduce the bending and twisting of the torso. The experiment reported in this paper tests this assumption and provides information on the utility of back belts. 1998 Elsevier Science B.V. All rights reserved.
Lumbar loading during lifting: a comparative study of three measurement techniques
Journal of Electromyography and Kinesiology, 2001
Low back loading during occupational lifting is thought to be an important causative factor in the development of low back pain. In order to regulate spinal loading in the workplace, it is necessary to measure it accurately. Various methods have been developed to do this, but each has its own limitations, and none can be considered a "gold standard". The purpose of the current study was to compare the results of three contrasting techniques in order to gain insight into possible sources of error to which each is susceptible. The three techniques were a linked segment model (LSM), an electromyographic (EMG)-based model, and a neural network (NN) that used both EMG and inertial sensing techniques. All three techniques were applied simultaneously to calculate spinal loading when eight volunteers performed a total of eight lifts in a laboratory setting. Averaged results showed that, in comparison with the LSM, the EMG technique calculated a 25.5±33.4% higher peak torque and the NN technique a 17.3±10.5% lower peak torque. Differences between the techniques varied with lifting speed and method of lifting, and could be attributed to differences in anthropometric assumptions, antagonistic muscle activity, damping of transient force peaks by body tissues, and, specific to the NN, underestimation of trunk flexion. The results of the current study urge to reconsider the validity of other models by independent comparisons.