Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-21 (of 21 Records) |
Query Trace: Breloff SP [original query] |
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Automated classification of the phases relevant to work-related musculoskeletal injury risks in residential roof shingle installation operations using machine learning
Dutta A , Breloff SP , Mahmud D , Dai F , Sinsel EW , Warren CM , Wu JZ . Buildings 2023 13 (6) Awkward kneeling in sloped shingle installation operations exposes roofers to knee musculoskeletal disorder (MSD) risks. To address the varying levels of risk associated with different phases of shingle installation, this research investigated utilizing machine learning to automatically classify seven distinct phases in a typical shingle installation task. The classification process relied on analyzing knee kinematics data and roof slope information. Nine participants were recruited and performed simulated shingle installation tasks while kneeling on a sloped wooden platform. The knee kinematics data were collected using an optical motion capture system. Three supervised machine learning classification methods (i.e., k-nearest neighbors (KNNs), decision tree (DT), and random forest (RF)) were selected for evaluation. The KNN classifier provided the best performance for overall accuracy. The results substantiated the feasibility of applying machine learning in classifying shingle installation phases from workers’ knee joint rotation and roof slope angles, which may help facilitate method and tool development for automated knee MSD risk surveillance and assessment among roofers. © 2023 by the authors. |
Deep learning-based estimation of whole-body kinematics from multi-view images
Nguyen KX , Zheng L , Hawke AL , Carey RE , Breloff SP , Li K , Peng X . Comput Vision Image Understanding 2023 235 It is necessary to analyze the whole-body kinematics (including joint locations and joint angles) to assess risks of fatal and musculoskeletal injuries in occupational tasks. Human pose estimation has gotten more attention in recent years as a method to minimize the errors in determining joint locations. However, the joint angles are not often estimated, nor is the quality of joint angle estimation assessed. In this paper, we presented an end-to-end approach on direct joint angle estimation from multi-view images. Our method leveraged the volumetric pose representation and mapped the rotation representation to a continuous space where each rotation was uniquely represented. We also presented a new kinematic dataset in the domain of residential roofing with a data processing pipeline to generate necessary annotations for the supervised training procedure on direct joint angle estimation. We achieved a mean angle error of 7.19° on the new Roofing dataset and 8.41° on the Human3.6M dataset, paving the way for employment of on-site kinematic analysis using multi-view images. © 2023 Elsevier Inc. |
Agreement of hip kinematics between two tracking marker configurations used with the coda pelvis during ergonomic roofing tasks
Moore KD , Hawke AL , Carey RE , Wu JZ , Breloff SP . J Mech Med Biol 2023 23 (3) The anterior and posterior iliac spine markers frequently used to define the pelvis, are commonly occluded during three-dimensional (3D) motion capture. The occlusion of these markers leads to the use of various tracking marker configurations on the pelvis, which affect kinematic results. The purpose of this investigation was to examine the agreement of CODA pelvis kinematic results when two different tracking marker configurations were used during roofing tasks. 3D motion data were collected on seven male subjects while mimicking two roofing tasks. Hip joint angles (HJAs) were computed using the CODA pelvis with two different tracking marker configurations, the trochanter tracking method (TTM), and virtual pelvis tracking method (VPTM). Agreement between tracking marker configurations was assessed using cross-correlations, bivariate correlations, mean absolute differences (MADs), and Bland-Altman (BA) plots. The correlations displayed no time lag and strong agreement (all r>0.83) between the HJA from the VPTM and TTM, suggesting the timing occurrence of variables are comparable between the two tracking marker configurations. The MAD between the VPTM and TTM displayed magnitude differences, but most of the differences were within a clinically acceptable range. Caution should still be used when comparing kinematic results between various tracking marker configurations, as differences exist. © 2023 World Scientific Publishing Company. |
Video-Based 3D pose estimation for residential roofing
Wang R , Zheng L , Hawke AL , Carey RE , Breloff SP , Li K , Peng X . Comput Methods Biomech Biomed Eng Imaging Vis 2022 1-9 Residential roofers are often exposed to awkward postures and motions in a prolonged time, which may not only reduce their body stability and increase fall potential, but also increase the risk of musculoskeletal disorders (MSDs). To assess their risks of fatal and musculoskeletal injuries, it is crucial to capture 3D body poses of workers during roofing tasks. In this paper, we proposed a novel two-stage motion estimation approach based on a convolution neural network to estimate residential roofer’s body poses using three-view video data. Our approach includes two stages: (1) use of an offline multi-view model to estimate the 3D pose in a single frame; (2) use of a multi-frame model to apply temporal convolutions to refine the multi-view outputs. The performance of the approach was evaluated by comparing our estimation with the gold-standard marker-based 3D human pose during one of the common residential roofing tasks–shingle installation. The evaluation results show that the proposed multi-frame model can effectively improve the accuracy of the coordinate sequence. Moreover, these results prove that the proposed video-based motion estimation approach can efficiently and accurately locate 3D body joints and pave the way for future onsite motion analysis during roofing activities. © This work was authored as part of the Contributor’s official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law. |
Spatiotemporal gait parameters while cross-slope residential roof walking
Breloff SP , Carey RE , Wade C , Waddell DE . Int J Ind Ergon 2022 87 Falls from residential roofs account for 80% of roofing industry fatalities. Furthermore, roofing work represents 44.7% of work in residual construction specialty trades and residential roofers count for 2.1% of overall workers in construction, with an anticipated growth in roofers of 14.9% by 2024. The purpose of the study was to evaluate the alterations in spatiotemporal gait parameters while traversing along a 6/12 pitched residential roof segment. Eighteen of the nineteen calculated spatiotemporal variables were statistically, significantly changed by walking across a 6/12 pitched simulated residential roof. The study clearly demonstrates that spatiotemporal gait variables increase and decrease while traversing across a residential roof. The changes in spatiotemporal parameters might suggest alterations to a person's balance system resulting in an increased risk of falling. The knowledge generated in the current study will be relevant to the residential roofing industry when it can be used in educational materials to increase awareness of how a roofer's altered gait while working on a pitched roof may increase their falling risk. © 2021 |
Natural prioritization tendencies during texting while walking
Brennan AC , Breloff SP . J Musculoskelet Res 2021 24 (3) Dual tasking (DT), or completing more than one task concurrently, has become a common practice. 1 This practice requires the allocation of one's limited attentional resources to different tasks in a proportion that allows for the safe execution and completion of both tasks.1 With nearly 70% of the adult and teen population owning a cell phone,2 it is unsurprising that cell phone-based DTs have become an everyday occurrence in the lives of many. Copyright © 2021 American Medical Association. All rights reserved. |
Application of Data Fusion via Canonical Polyadic Decomposition in Risk Assessment of Musculoskeletal Disorders in Construction: Procedure and Stability Evaluation
Dutta A , Breloff SP , Dai F , Sinsel EW , Warren CM , Carey RE , Wu JZ . J Constr Eng Manage 2021 147 (8) Missing data is a common problem in data collection for work-related musculoskeletal disorder (WMSD) risk-assessment studies. It can cause incompleteness of risk indicators, leading to erroneous conclusion on potential risk factors. Previous studies suggested that data fusion is a potential way to solve this issue. This research evaluated the numerical stability of a data fusion technique that applies canonical polyadic decomposition (CPD) for WMSD risk assessment in construction. Two knee WMSD risk-related data sets - three-dimensional (3D) knee rotation (kinematics) and electromyography (EMG) of five knee postural muscles - collected from previous studies were fused for the evaluation. By comparing the consistency performance with and without data fusion, it revealed that for all low to high proportion of missing data (10%-70%) from both kinematics and EMG data sets, the WMSD risk assessment using fused data sets outperformed using unfused kinematics data sets. For large proportions of missing data (>50%) from both kinematics and EMG data sets, better performance was observed by using fused data sets in comparison with unfused EMG data sets. These findings suggest that data fusion using CPD generates a more reliable risk assessment compared with data sets with missing values and therefore is an effective approach for remedying missing data in WMSD risk evaluation. © 2021 American Society of Civil Engineers. |
An alternative method for analyzing the slip potential of workers on sloped surfaces
Dong RG , Wu JZ , Dai F , Breloff SP . Saf Sci 2021 133 Slips and falls on sloped roof surfaces remain an important safety issue among construction workers. The slip potential has been conventionally analyzed and assessed primarily based on ground reaction forces, which cannot differentiate the specific roles of each of the force factors (e.g., workers’ motions-induced dynamic forces and slope-induced static forces) contributing to the slip potential. Their differentiation may enhance the understanding of the slip mechanisms on the sloped roof surfaces and help develop effective walking and working strategies/tactics to minimize the dangerous slips on the elevated roofs. Hence, the objective of this study is to develop a biodynamic method as an additional tool for analyzing the slip potential of a worker walking or working on sloped roof surfaces. A whole-body biodynamic model is proposed and used to develop the alternative method, in which the slip potential is expressed as an analytical function of its major controlling factors including coefficient of friction, slope angle, and biodynamic forces. Some experimental data available in the literature are used to demonstrate the application of the proposed method. The results suggest that the slope may not change the basic trends of the biodynamic forces, but the slope may affect their magnitudes, which can be explained using the system's energy equation also derived from the whole-body biodynamic model. The analytical results suggest that reducing the body acceleration in uphill direction or the deceleration in downhill direction can reduce the slip potential. ‘Zigging’ and ‘zagging’ walking on a sloped surface may also reduce the slip potential, as it reduces the effective slope angle. The proposed biodynamic theory can be used to enhance the safety guidelines not only for roofers but also for people walking on ramps, inclined walkways, and mountain terrains. |
Inclination angles during cross-slope roof walking
Breloff SP , Carey RE , Wade C , Waddell DE . Saf Sci 2020 132 Residential roofers have the highest rate of falls in the construction sector with injuries and fatalities costing billions of dollars annually. The sloped roof surface is the most predominant component within the residential roof work environment. Postural stability on a sloped work environment is not well studied. Calculating inclination angles (IAs) using the lateral ankle marker could be a quality measure to determine how cross-slope roof walking will influence stability. Will cross-slope roof-walking effect anterior-posterior (AP) and medial-lateral (ML) IAs in adult males? Eleven adult males participated in two testing sessions-level and cross-slope roof gait session on a 6/12 pitched roof segment. Changes in AP and ML IAs between conditions were compared at: heel strike (HS) and toe off (TO). Legs were analyzed separately due to the cross-slope walking. The left foot was 'higher' on the sloped roof and the right was 'lower.' Significant increases (p <= 0.006) in IAs were observed due to the sloped roof in all conditions except the AP 'lower' leg (p = 0.136). Increases in IA suggest a decrease in postural stability as the body will result in greater sway compared to a natural posture. Increases in AP IAs may cause slipping in the anterior or posterior direction as the normal force will decrease during HS and TO. In the ML direction, fall risk is increased and more stress is placed on the hip abductors in order to reduce falling. Thus traversing a sloped roof surface reduces stability of healthy workers and escalates injury/fall risk factors. |
Fusing imperfect experimental data for risk assessment of musculoskeletal disorders in construction using canonical polyadic decomposition
Dutta A , Breloff SP , Dai F , Sinsel EW , Carey RE , Warren CM , Wu JZ . Autom Constr 2020 119 Field or laboratory data collected for work-related musculoskeletal disorder (WMSD) risk assessment in construction often becomes unreliable as a large amount of data go missing due to technology-induced errors, instrument failures or sometimes at random. Missing data can adversely affect the assessment conclusions. This study proposes a method that applies Canonical Polyadic Decomposition (CPD) tensor decomposition to fuse multiple sparse risk-related datasets and fill in missing data by leveraging the correlation among multiple risk indicators within those datasets. Two knee WMSD risk-related datasets—3D knee rotation (kinematics) and electromyography (EMG) of five knee postural muscles—collected from previous studies were used for the validation and demonstration of the proposed method. The analysis results revealed that for a large portion of missing values (40%), the proposed method can generate a fused dataset that provides reliable risk assessment results highly consistent (70%–87%) with those obtained from the original experimental datasets. This signified the usefulness of the proposed method for use in WMSD risk assessment studies when data collection is affected by a significant amount of missing data, which will facilitate reliable assessment of WMSD risks among construction workers. In the future, findings of this study will be implemented to explore whether, and to what extent, the fused dataset outperforms the datasets with missing values by comparing consistencies of the risk assessment results obtained from these datasets for further investigation of the fusion performance. |
The effect of various cell phone related activities on gait kinematics
Brennan AC , Breloff SP . J Musculoskelet Res 2019 22 Background: With cell phone use and ownership on the rise, daily circumstances often require individuals to divide attentional resources between walking and a cell phone-related task. This division of attention has been found to detrimentally effect task performance, making pedestrian cell phone usage an increasing safety concern. However, most studies have investigated the impact of dual-Tasks on situational awareness and few have focused on tasks other than texting. Therefore, this study aimed to investigate the effect of various cell phone-related tasks on lower limb kinematics during walking. Methods: Fourteen healthy, college-Aged subjects completed gait analysis trials in five walking conditions, one single-Task walking condition and four dual task conditions: Walk+Converse, Walk+Read (Simple), Walk+Read (Difficult), and Walk+Text. Subjects' movements were recorded with a motion capture system and peak sagittal plane lower extremity joint angles, gait velocity, and stride length were calculated. Results: Of the eight kinematic outcome measures analyzed, all but one revealed some significant (p < 0.05) differences between dual-Task walking conditions. Gait velocity and stride length both decreased due to the addition of the dual tasking, with the magnitude of the reduction becoming more apparent with the increased difficulty of the cell phone-based task. Conclusion: This study supports a fundamental change to gait kinematics in response to cell phone use while walking, with the magnitude of impact being directly related to the complexity of the secondary task. The significant changes to gait kinematics in complex dual-Task situations could present a threat to balance. |
Effects of working posture and roof slope on activation of lower limb muscles during shingle installation
Dutta A , Breloff SP , Dai F , Sinsel EW , Warren CM , Carey RE , Wu JZ . Ergonomics 2020 63 (9) 1-17 Awkward and extreme kneeling during roofing generates high muscular tension which can lead to knee musculoskeletal disorders (MSDs) among roofers. However, the combined impact of roof slope and kneeling posture on the activation of the knee postural muscles and their association to potential knee MSD risks among roofers have not been studied. The current study evaluated the effects of kneeling posture and roof slope on the activation of major knee postural muscles during shingle installation via a laboratory assessment. Maximum normalized electromyography (EMG) data were collected from knee flexor and extensor muscles of seven subjects, who mimicked the shingle installation process on a slope-configurable wooden platform. The results revealed a significant increase in knee muscle activation during simulated shingle installation on sloped rooftops. Given the fact that increased muscle activation of knee postural muscles has been associated with knee MSDs, roof slope and awkward kneeling posture can be considered as potential knee MSD risk factors.Practitioner Summary: This study demonstrated significant effects of roof slope and kneeling posture on the peak activation of knee postural muscles. The findings of this study suggested that residential roofers could be exposed to a greater risk of developing knee MSDs with the increase of roof slope during shingle installation due to increased muscle loading. |
The effect of blood glucose on quiet standing balance in young healthy individuals
Breloff SP , Bachman JL , Lugade VA , Stuka AD . Biomed Eng (Singapore) 2020 32 (2) Falling is one of the leading causes of accidental injury and death among elderly adults and construction workers, with costs exceeding US31 billion each year. Having good balance reduces the likelihood of falling - therefore it is important to determine which possible factors might influence balance. The purpose of this study was to determine if consuming three different types of breakfast altered blood glucose levels in such a way that young healthy individual's balance control was compromised. Balance was then measured while the subjects completed single- and dual-task standing trials with eyes open and closed. Although changing blood glucose did alter quiet standing balance - as measured by the separation distance between the COG and COP, the velocity of the COM, and the total distance traveled by the COG and COP along the anterior-posterior (AP) and medial-lateral (ML) axes - the results were contradictory to what was hypothesized. Subjects with lower blood glucose swayed less than those with higher blood glucose. This could potentially be due to the habitual skipping of breakfast in young adults. Though the changing of blood glucose did influence quiet standing balance of young healthy adults, it was not in a way which increased the risk of falling. |
Kneeling trunk kinematics during simulated sloped roof shingle installation
Breloff SP , Carey RE , Dutta A , Sinsel EW , Warren CM , Dai F , Wu JZ . Int J Ind Ergon 2020 77 Trunk musculoskeletal disorders are common among residential roofers. Addressing this problem requires a better understanding of the movements required to complete working tasks, such as affixing shingles on a sloped residential roof. We analyzed the extent to which the trunk kinematics during a shingling process are altered due to different angles of roof slope. Eight male subjects completed a kneeling shingle installation process on three differently sloped roof surfaces. The magnitude of the trunk kinematics was significantly influenced by both slope and task phase of the shingling process, depending on the metric. The results unequivocally point to roof slope and task phase as significant factors altering trunk kinematics. However, extension of the results to roofing workers should be done carefully, depending on the degree to which the study protocol represents the natural setting. Future studies on shingle installation in residential roofing should absolutely consider capturing a wider array of shingling procedures in order to encapsulate all the possible methods that are used due to the lack of a standardized procedure. |
Identifying potentially risky phases leading to knee musculoskeletal disorders during shingle installation operations
Dutta A , Breloff SP , Dai F , Sinsel EW , Warren CM , Wu JZ . J Constr Eng Manage 2020 146 (3) Repeated and prolonged awkward kneeling can result in musculoskeletal disorders (MSD) in construction roofers. However, a task-specific risk assessment for roofers' knee injuries is still missing in the literature. This study identified a ranking-based ergonomic method for suggesting potentially risky phases that may increase knee MSD risk during shingle installation operations. On a slope-adjustable wooden platform in a laboratory setting, nine subjects performed shingle installations that included seven phases: (1) reaching for shingles, (2) placing shingles, (3) grabbing nail gun, (4) moving to first nailing position, (5) nailing shingles, (6) replacing nail gun, and (7) returning to upright position. Flexion, abduction, adduction, and internal and external knee rotations were measured to assess relative risks of these phases by ranking them with a scoring model. The ranking results revealed that the phases of placing shingles and nailing shingles lead to the most knee MSD risk exposure, and awkward flexion, abduction, and adduction involved in these phases can significantly contribute to the potential knee MSD risk measurement. By using the ranking-based method, this study suggested that certain phases of the shingle installation process may increase knee MSD risk, which is useful for developing effective interventions to reduce knee injury risk exposures from roof shingle installation. |
Are knee savers and knee pads a viable intervention to reduce lower extremity musculoskeletal disorder risk in residential roofers
Breloff SP , Sinsel EW , Dutta A , Carey RE , Warren CM , Dai F , Ning S , Wu JZ . Int J Ind Ergon 2019 74 One factor commonly associated with musculoskeletal disorder risk is extreme postures. To lessen this risk, extreme postures should be reduced using proactive and prevention-focused methods. The effect of combinations of two interventions, knee pads and knee savers, on lower extremity kinematics during deep or near full flexion kneeling on differently sloped surfaces was analyzed. Nine male subjects were requested to keep a typical resting posture while kneeling on a sloped roofing simulator with and without knee pads and knee savers. Three-dimensional peak knee kinematics were recording using a motion capture system. The kinematic data were analyzed with a two-way—4(intervention) X 3(slope)—repeated measure analysis of variance (ANOVA). It was observed that knee pads did not alter lower extremity kinematics in a way that may reduce musculoskeletal injury risk, but they do provide comfort. Knee savers did statistically significantly reduce peak lower extremity kinematics, however these changes were small and it is uncertain if the changes will reduce musculoskeletal injury risk. This study has provided initial data that supports the use of knee savers as a potential intervention to reduce musculoskeletal disorder risk due to lower extremity joint angles on a sloped surface, nonetheless, further testing involving other musculoskeletal disorder risk factors is needed prior to a conclusive recommendation. |
Biomechanical modeling of deep squatting: Effects of the interface contact between posterior thigh and shank
Wu JZ , Sinsel EW , Carey RE , Zheng L , Warren CM , Breloff SP . J Biomech 2019 96 109333 Epidemiological studies indicate that occupational activities that require extended deep knee flexion or kneeling are associated with a higher prevalence of knee osteoarthritis. In many sport activities, such as a catcher in a baseball or a softball game, athletes have to make repetitive deep squatting motions, which have been associated with the development of osteochondritis dissecans. Excessive deep knee flexion postures may cause excessive loading in the knee joint. In deep knee flexion postures, the posterior aspect of the shank will contact the posterior thigh, resulting in a compressive force within the soft tissues. The current study was aimed at analyzing the effects of the posterior thigh/shank contact on the joint loading during deep knee flexion in a natural knee. An existing, whole body model with detailed anatomical components of the knee (AnyBody) has been adopted and modified for this study. The effects of the posterior thigh/shank contact were evaluated by comparing the results of the inverse dynamic analysis for two scenarios: with and without the posterior thigh/shank contact force. Our results showed that, in a deep squatting posture (knee flexion 120+ degrees), the posterior thigh/shank contact helps reduce the patellofemoral (PF) and tibiofemoral (TF) normal contact forces by 42% and 57%, respectively. |
Assessing work-related risk factors for musculoskeletal knee disorders in construction roofing tasks
Breloff SP , Dutta A , Dai F , Sinsel EW , Warren CM , Ning X , Wu JZ . Appl Ergon 2019 81 102901 Roofers often suffer from musculoskeletal disorders (MSDs) to their knees due to spending a large amount of time kneeling while performing work-related roofing activities on sloped rooftops. Several ergonomic studies have identified kneeling as a potential risk factor for knee injuries and disorders. Existing biomechanical models and sensor technologies used to assess work-related risk factors for different construction trades are not applicable in roof work settings especially on slanted rooftop surfaces. This work assesses the impacts of work-related factors, namely working posture and roof slope, on the potential risk of developing knee MSDs due to residential roofing tasks in a laboratory setting. Nine human subjects participated in the experiment and mimicked shingle installation on a slope-configurable wooden platform. Maximum angles of right and left knee flexion, abduction, adduction, and axial rotation (internal and external) were measured as risk indicators using a motion capture system under different roof slope settings. The results demonstrated that roof slope, working posture and their interaction may have significant impacts on developing knee MSDs during roofing activities. Knees are likely to be exposed to increased risk of MSDs due to working in a dynamic kneeling posture during shingle installation. In our study, flexion in both knees and adduction in the right knee were found lower in high-pitched rooftops; however, abduction in the left knee and internal rotation in the right knee were found higher during shingle installation. Hence proper attention is needed for these situations. This study provides useful information about the impact of roof work settings on knee MSDs development, which may facilitate effective interventions such as education, training, and tools to prevent knee injuries in construction roofing tasks. |
Lower extremity kinematics of cross-slope roof walking
Breloff SP , Wade C , Waddell DE . Appl Ergon 2019 75 134-142 Working conditions of residential roofers expose them to a unique sloped environment. The purpose of this study is to determine in what way traversing across a sloped/roof surface alters lower extremity kinematics of the upslope and downslope legs compared to level walking. College aged males negotiated across a pitched (26 degrees) roof segment during which lower extremity three-dimensional kinematics were calculated. One foot was higher on the slope and one was lower for the duration of cross slope walking. Overall, cross-slope walking on a 26 degree roof significantly altered 77% of the measured lower extremity variables compared to level self-selected pace walking. The data suggest that roof pitch incite significant differences in crossslope walking of the kinematics in the lower extremity between the upslope and down slope limbs when compared to level surface walking. These alterations could temporarily alter proprioception which may in turn lead to increased falls and musculoskeletal injury, though further study is needed. |
Multi-segmented trunk motion of healthy non-elderly adults in different decades of life
Breloff SP , Chou LS . Biomed Eng (Singapore) 2017 29 (4) Traditionally, gait analysis models the trunk as one rigid body segment. This approach has limitations; it does not capture all the movements of this area of the body throughout locomotion. Lower-extremity-gait kinematics do not routinely change in healthy non-elderly adults in different decades of life; however, it is unknown if trunk kinematics will be altered during different activities of daily living as a function of age. The purpose of this study was to determine if a previously validated multi-segmented trunk model would detect trunk movement variations in non-elderly healthy adults in different decades of life. Thirty-four non-elderly healthy adults in various decades of life (20-29 years, 30-39 years, 40-49 years, and 50-59 years) completed two tasks of ambulatory daily living (level walking and stair descent). Trunk maximum angle during the gait cycle, timing of the trunk maximum angle during the gait cycle and trunk range of motion were examined using analysis of variance procedures. Findings are that age group did not affect the trunk kinematics of individuals in different decades of life, but that may not represent the experiences of elderly individuals. |
Three-dimensional multi-segmented spine joint reaction forces during common workplace physical demands/activities of daily living
Breloff SP , Chou LS . Biomed Eng (Singapore) 2017 29 (4) 1750025 Objective: The quantification of inter-segmental spine joint reaction forces during common workplace physical demands. Background: Many spine reaction force models have focused on the L5/S1 or L4/L5 joints to quantify the vertebral joint reaction forces. However, the L5/S1 or L4/L5 approach neglects most of the intervertebral joints. Methods: The current study presents a clinically applicable and noninvasive model which calculates the spinal joint reaction forces at six different regions of the spine. Subjects completed four ambulatory activities of daily living: level walking, obstacle crossing, stair ascent, and stair descent. Results: Peak joint spinal reaction forces were compared between tasks and spine regions. Differences existed in the bodyweight normalized vertical joint reaction forces where the walking (8.05±3.19N/kg) task had significantly smaller peak reaction forces than the stair descent (12.12±1.32N/kg) agreeing with lower extremity data comparing walking and stair descent tasks. Conclusion: This method appears to be effective in estimating the joint reaction forces using a segmental spine model. The results suggesting the main effect of peak reactions forces in the segmental spine can be influenced by task. |
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