Torso Segment Parameter Prediction in Working Adults

2018 ◽  
Vol 62 (1) ◽  
pp. 1257-1261
Author(s):  
Zachary Merrill ◽  
Subashan Perera ◽  
Rakié Cham
Keyword(s):  
Statistical Models ◽  
Injury Risk ◽  
Center Of Mass ◽  
Whole Body ◽  
Radius Of Gyration ◽  
Working Adults ◽  
Biomechanical Models ◽  
Scan Data ◽  
Body Segment Parameters ◽  
The Impact

Body segment parameters (BSPs) such as segment mass, center of mass, and radius of gyration are used as inputs in static and dynamic ergonomic and biomechanical models used to predict joint and muscle forces, and related risks of musculoskeletal injury. Because these models are sensitive to BSP values, accurate and representative parameters are necessary for injury risk prediction. While previous studies have determined segment parameters in the general population, as well as the impact of age and obesity levels on these parameters, estimated errors in the prediction of BSPs can be as large as 40% (Durkin, 2003). Thus, more precise values are required for attempting to predict injury risk in individuals. This study aims to provide statistical models for predicting torso segment parameters in working adults using whole body dual energy x-ray absorptiometry (DXA) scan data along with a set of anthropometric measurements. The statistical models were developed on a training subset of the study population, and validated on a testing subset. When comparing the model predictions to the actual BSPs of the testing subset, the predictions were, on average, within 5% of the calculated parameters, while previously developed predictions (de Leva, 1996) had average errors of up to 30%, indicating that the new statistical models greatly increase the accuracy in predicting BSPs.

Impact of Age and Body Mass Index on Anthropometry in Working Adults

2017 ◽  
Vol 61 (1) ◽  
pp. 1341-1345 ◽  
Author(s):  
Zachary Merrill ◽  
April Chambers ◽  
Rakié Cham
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Center Of Mass ◽  
Biomechanical Model ◽  
Whole Body ◽  
Working Adults ◽  
Biomechanical Models ◽  
Scan Data ◽  
Body Segment Parameters ◽  
The Impact

Body segment parameters (BSPs) such as segment mass and center of mass are used as inputs in ergonomic design and biomechanical models to predict the risk of musculoskeletal injuries. These models have been shown to be sensitive to the BSP values used as inputs, demonstrating the necessity of using accurate and representative parameters. This study aims to provide accurate BSPs by quantifying the impact of age and body mass index on torso and thigh mass and center of mass in working adults using whole body dual energy x-ray absorptiometry (DXA) scan data. The results showed significant effects of gender, age, and body mass index (BMI) on torso and thigh mass and center of mass, as well as significant effects of age and BMI within genders, indicating that age, gender, and BMI need to be taken into account when predicting BSPs in order to calculate representative ergonomic and biomechanical model outputs.

scholarly journals Differences in Geriatric Anthropometric Data Between DXA-Based Subject-Specific Estimates and Non-Age-Specific Traditional Regression Models

2011 ◽  
Vol 27 (3) ◽  
pp. 197-206 ◽  
Author(s):  
April J. Chambers ◽  
Alison L. Sukits ◽  
Jean L. McCrory ◽  
Rakié Cham
Keyword(s):  
Regression Models ◽  
Whole Body ◽  
Radius Of Gyration ◽  
Specific Method ◽  
Body Segment ◽  
Anthropometric Data ◽  
Subject Specific ◽  
And Gender ◽  
Body Segment Parameters ◽  
The Impact

Age, obesity, and gender can have a significant impact on the anthropometrics of adults aged 65 and older. The aim of this study was to investigate differences in body segment parameters derived using two methods: (1) a dual-energy x-ray absorptiometry (DXA) subject-specific method (Chambers et al., 2010) and (2) traditional regression models (de Leva, 1996). The impact of aging, gender, and obesity on the potential differences between these methods was examined. Eighty-three healthy older adults were recruited for participation. Participants underwent a whole-body DXA scan (Hologic QDR 1000/W). Mass, length, center of mass, and radius of gyration were determined for each segment. In addition, traditional regressions were used to estimate these parameters (de Leva, 1996). A mixed linear regression model was performed (α = 0.05). Method type was significant in every variable of interest except forearm segment mass. The obesity and gender differences that we observed translate into differences associated with using traditional regressions to predict anthropometric variables in an aging population. Our data point to a need to consider age, obesity, and gender when utilizing anthropometric data sets and to develop regression models that accurately predict body segment parameters in the geriatric population, considering gender and obesity.

The acute effects of vibratory stimuli during exercise on the sensorimotor control of the shoulder complex: A pilot study

2021 ◽  
pp. 1-9
Author(s):  
Somu Kotoshiba ◽  
Noriaki Maeda ◽  
Masanori Morikawa ◽  
Mitsuhiro Yoshimi ◽  
Shogo Sakai ◽  
...  
Keyword(s):  
Upper Limb ◽  
Shoulder Joint ◽  
Injury Risk ◽  
Weight Bearing ◽  
Sensorimotor Control ◽  
Whole Body ◽  
Partial Weight Bearing ◽  
Serratus Anterior ◽  
The Impact ◽  
Partial Weight

BACKGROUND: Functional stability of the shoulder requires a balance of active forces, passive forces, and control subsystems of the joint complex. Although whole-body vibration enhances shoulder muscle function and proprioception, the impact of vibration on the sensorimotor control of the shoulder joint remains unclear. OBJECTIVE: To investigate the acute effect of vibratory stimuli on the sensorimotor control of the shoulder joint. METHODS: Fifteen male participants (age, 22.7 ± 2.3 years) were included and performed the exercise in a modified push-up position with partial weight-bearing on a vibration platform with and without vibratory stimuli. The vibration protocol included six sets lasting for 30 s each with a 30-s rest between sets. The main outcome measures included the upper limb static stability test, Upper Quarter Y Balance Test (UQYBT), and electromyography data of the upper limb. RESULTS: Vibratory stimuli resulted in an increased UQYBT score (all directions; P< 0.01) and infraspinatus, serratus anterior, and lower trapezius muscle activity (P< 0.05) between pre- and post-exercise versus the control condition. Stabilometric parameters showed no significant interaction between condition and time. CONCLUSIONS: Vibratory stimuli could maximize training benefits while limiting injury risk for athletes. Our findings could guide the development of rehabilitation programs for patients with shoulder instability.

scholarly journals The impact of tool selection on back and wrist injury risk in tying steel reinforcement bars: a single case experiment

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Helen Lingard ◽  
Isaac Selva Raj ◽  
Noel Lythgo ◽  
Olga Troynikov ◽  
Chris Fitzgerald
Keyword(s):  
Risk Factors ◽  
Injury Risk ◽  
Single Case ◽  
Wearable Sensors ◽  
Musculoskeletal Injury ◽  
Steel Reinforcement ◽  
Whole Body ◽  
Work Related ◽  
Trunk Inclination ◽  
The Impact

The paper explores the risk of work-related musculoskeletal injury in tying steel reinforcement bars. Three tools are compared to determine the extent to which ergonomic tools can reduce the risk of injury to the back and wrist in steel-tying. A whole body system of wearable sensors was used to measure biomechanical risk in tying. Three tools were assessed to determine their impact on the risk of work-related musculoskeletal injury when used at different heights. These were: a conventional pincer-cutting tool; a power-driven tying tool, and a long handled stapler tool. No tool was found to work best in all situations. The long handled stapler tool significantly reduced trunk inclination when used from ground to shoulder height, but produced higher trunk extension (backward bending) when used above shoulder height. The power tying tool did not reduce the need to bend when working at lower work heights. The power-tying tool produced significantly lower peak wrist flexion values compared to the conventional pincer-cutter tool at all work heights except overhead. The power tying tool involved significantly lower levels of wrist rotation than the conventional pincer-cutter tool at all work heights above knee level. Many assessments of ergonomic risk factors in construction rely on observational methods. The use of small, lightweight wearable sensors permits the objective measurement of biomechanical risk factors for work-related musculoskeletal injury, as well as providing objective performance data that can be used in the design and selection of task-specific tools. Our analysis of work by height also provides insight into the way in which risk factors and reduction opportunities afforded by different tools vary depending on the height at which work is to be performed.

Effect of Trunk Segment Boundary Definitions on Frontal Plane Segment Inertial Calculations

2018 ◽  
Vol 34 (3) ◽  
pp. 232-235 ◽  
Author(s):  
Zachary Merrill ◽  
Grace Bova ◽  
April Chambers ◽  
Rakié Cham
Keyword(s):  
Center Of Mass ◽  
Frontal Plane ◽  
Dual Energy ◽  
Segment Length ◽  
Radius Of Gyration ◽  
Morbidly Obese ◽  
Mass Center ◽  
X Ray ◽  
Trunk Segment ◽  
The Impact

When defining trunk body segment parameters, such as segment length, mass, center of mass location, and radius of gyration, it is necessary to understand and define consistent, anatomically relevant segment boundaries. In addition to the differences in reported trunk parameters due to different data collection and analysis methods (such as cadaver studies and imaging methods), many previous publications have also used differing definitions of the trunk segment. The objective of this study was to determine the effect of differences in trunk segment definitions and obesity on the calculated mass, center of mass, and radius of gyration using dual-energy X-ray absorptiometry anthropometry calculations. Twenty-three participants were recruited in normal weight and morbidly obese body mass index categories. A frontal plane dual-energy X-ray absorptiometry scan was taken of each participant, and 3 trunk segment delineations used by Chambers, de Leva, and Zatsiorsky were used to calculate the trunk parameters. The results showed statistically significant effects of segmentation definition and obesity on the trunk parameters calculated. Because of the potential impacts on static modeling and inverse dynamics calculations, it is important to determine which trunk segmentations are most appropriate for specific applications and to account for the impact of obesity within individuals.

scholarly journals THE INFLUENCE OF IMPACT SPEED ON CHEST INJURY OUTCOME IN WHOLE BODY FRONTAL SLED IMPACTS

Transport ◽  
2021 ◽  
Vol 35 (6) ◽  
pp. 669-678
Author(s):  
Sen Xiao ◽  
Fuhao Mo ◽  
Jikuang Yang ◽  
Jing Huang ◽  
Zhi Xiao ◽  
...  
Keyword(s):  
Injury Risk ◽  
Human Subjects ◽  
Chest Injury ◽  
Whole Body ◽  
Fe Model ◽  
Virtual Design ◽  
Test Configuration ◽  
Impact Speed ◽  
Chest Injuries ◽  
The Impact

While the seatbelt restraint has significantly improved occupant safety, the protection efficiency still needs further enhance to reduce the consequence of the crash. Influence of seatbelt restraint loading on chest injury under 40 km/h has been tested and documented. However, a comprehensive profiling of the efficiency of restraint systems with various impact speeds has not yet been sufficiently reported. The purpose of this study is to analyse the effect of the seatbelt loadings on chest injuries at different impact speeds utilizing a high bio-fidelity human body Finite Element (FE) model. Based on the whole-body frontal sled test configuration, the current simulation is setup using a substitute of Post-Mortem Human Subjects (PMHS). Chest injury outcomes from simulations are analysed in terms of design variables, such as seatbelt position parameters and collision speed in a full factorial experimental design. These outcomes are specifically referred to strain-based injury probabilities and four-point chest deflections caused by the change of the parameters. The results indicate that impact speed does influence chest injury outcome. The ribcage injury risk for more than 3 fractured ribs will increase from around 40 to nearly 100% when the impact speed change from 20 to 40 km/h if the seatbelt positioned at the middle-sternum of this study. Great injuries to the chest are mainly caused by the change of inertia, which indicates that chest injuries are greatly affected by the impact speed. Furthermore, the rib fracture risk and chest deflection are nonlinearly correlated with the change of the seatbelt position parameters. The study approach can serve as a reference for seatbelt virtual design. Meanwhile, it also provides basis for the research of chest injury mechanism.

scholarly journals Monitoring the Performance of Alpine Skiers with Inertial Motion Units: Practical and Methodological Considerations

2021 ◽  
Author(s):  
Matej Supej ◽  
H-C Holmberg
Keyword(s):  
Inertial Sensors ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Whole Body ◽  
Navigation Systems ◽  
Inertial Motion ◽  
Biomechanical Models ◽  
Alpine Skiers ◽  
Satellite Navigation Systems ◽  
Methodological Considerations

AbstractAlthough reliable feedback is crucial to improving the performance of competitive alpine skiers, the coach's eye may not be sensitive enough to detect small, but highly significant “mistakes”. Monitoring of the performance of alpine ski racers by inertial motion units (IMU) has proven to be of value in this context and here we summarize practical and methodological aspects of this approach. Methodologically, the IMUs employed should combine high sampling frequencies with minimal signal drift. The sensors should be positioned to sense the movement of the bones in a given body segment while being protected as much as possible against impact with the ski gates. The data obtained, often synchronized with input from Global Satellite Navigation Systems (GNSS), are usually refined utilizing advanced biomechanical models and other computerized approaches. In practice, the combination of inertial sensors and GNSS allows accurate monitoring of skiing kinematics (technique) and the movement of the skier’s center-of-mass, also allowing analysis of both whole-body vibrations (WBV) and loss of mechanical energy. Presentation of the findings to coaches and athletes can be facilitated by synchronizing them with video recordings. Recent advances in IMU technology, including miniaturization, wireless communication, direct storage of data in the cloud, and processing with artificial intelligence may allow these sensors, in-combination with GNSS, to become real-time virtual alpine ski coaches, perhaps the next step in the development of this sport.

Effect of Upper and Lower Extremity Control Strategies on Predicted Injury Risk During Simulated Forward Falls: A Study in Healthy Young Adults

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
JiaHsuan Lo ◽  
James A. Ashton-Miller
Keyword(s):  
Kinetic Energy ◽  
Injury Risk ◽  
Impact Force ◽  
The Body ◽  
Whole Body ◽  
Joint Control ◽  
Negative Work ◽  
Impact Forces ◽  
Hip Flexion ◽  
The Impact

Fall-related wrist fractures are common at any age. We used a seven-link, sagittally symmetric, biomechanical model to test the hypothesis that systematically alterations in the configuration of the body during a forward fall from standing height can significantly influence the impact force on the wrists. Movement of each joint was accomplished by a pair of agonist and antagonist joint muscle torque actuators with assigned torque-angle, torque-velocity, and neuromuscular latency properties. Proportional-derivative joint controllers were used to achieve desired target body segment configurations in the pre- and∕or postground contact phases of the fall. Outcome measures included wrist impact forces and whole-body kinetic energy at impact in the best, and worst, case impact injury risk scenarios. The results showed that peak wrist impact force ranged from less than 1kN to more than 2.5kN, reflecting a fourfold difference in whole-body kinetic energy at impact (from less than 40J to more than 160J) over the range of precontact hip and knee joint angles used at impact. A reduction in the whole-body kinetic energy at impact was primarily associated with increasing negative work associated with hip flexion. Altering upper extremity configuration prior to impact significantly reduced the peak wrist impact force by up to 58% (from 919Nto2212N). Increased peak wrist impact forces associated greater shoulder flexion and less elbow flexion. Increasing postcontact arm retraction can reduce the peak wrist impact force by 28% (from 1491Nto1078N), but postcontact hip and knee rotations had a relatively small effect on the peak wrist impact force (8% reduction; from 1411Nto1303N). In summary, the choice of the joint control strategy during a forward fall can significantly affect the risk of wrist injury. The most effective strategy was to increase the negative work during hip flexion in order to dissipate kinetic energy thereby reducing the loss in potential energy prior to first impact. Extended hip or elbow configurations should be avoided in order to reduce forearm impact forces.

Transport and Chronic Injuries Caused by Improper Use of Cell Phones：Evidences from 41 Studies (Preprint)

2020 ◽  
Author(s):  
Xinxi Cao ◽  
Yangyang Cheng ◽  
Chenjie Xu ◽  
Yabing Hou ◽  
Hongxi Yang ◽  
...  
Keyword(s):  
Human Body ◽  
Cell Phone ◽  
Injury Risk ◽  
Negative Impact ◽  
Mental Disease ◽  
Cell Phones ◽  
Cell Phone Use ◽  
Improper Use ◽  
Chronic Injuries ◽  
The Impact

BACKGROUND Cell phone use brought convenience to people, but using phones for a long period of time or in the wrong way and with a wrong posture might cause damage to the human body. OBJECTIVE To assess the impact of improper cell phone use on transport and chronic injuries. METHODS Studies were systematically searched in PubMed, EMBASE, Cochrane, and Web of Science up to April 4, 2019 and relevant reviews were searched to identify additional studies. A random-effects model was used to estimate the overall pooled estimates. RESULTS Cell phone users were at a higher risk for transport injuries (RR: 1.37, 95%CI: 1.221.55), long-term use of cell phones increased the transport injury risk to non-use or short-term use (RR: 2.10, 95% CI: 1.632.70). Neoplasm risk caused by cell phone use was 1.07 times that of non-use (95% CI: 1.011.14); Compared with non-use, cell phone use had a higher risk of eye disease, with a risk of 2.03 (95% CI: 1.273.23), the risk of mental disease was 1.26 (95% CI: 1.171.35), the risk of neurological disorder was 1.16 (95% CI: 1.021.32), and a pooled risk of other chronic injuries was 1.20 (95% CI: 0.981.59). CONCLUSIONS Cell phone use at inappropriate situations has a negative impact on the human body. Therefore, it is necessary to use cell phones correctly and reasonably.

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