Physiological and biomechanical responses to a prolonged repetitive asymmetric lifting activity

Ergonomics ◽  
2014 ◽  
Vol 57 (4) ◽  
pp. 575-588 ◽  
Author(s):  
Jay P. Mehta ◽  
Steven A. Lavender ◽  
Richard J. Jagacinski
Author(s):  
Xueke Wang ◽  
Steven A. Lavender ◽  
Carolyn Sommerich

Objective: To explore the change of muscular and biomechanical responses in different load stability and visual access conditions during an asymmetric lifting task. Background: Previous studies found that lifting unstable loads resulted in changes to the biomechanical loads experienced by the spine and upper extremities. However, researchers have not extensively investigated behaviors when people lift potentially unstable loads. It was hypothesized that lifting a potentially unstable load can lead to changes in lifting behavior, which may be mitigated by visual access to the load. Method: Fourteen volunteers lifted either a stable load or a potentially unstable load that could move within the container during the lifting task. In half of the lifting conditions, the box was covered to restrict visual access when lifting. Spine kinematic and kinetic measures and surface electromyographic (EMG) signals from back, shoulder, and arm muscles were obtained. Results: Lifts of the stable load were faster and generally had higher peak muscle activations than lifts of the potentially unstable load. Participants had less spine flexion when handling the potentially unstable load without visual access. Conclusion: When lifting and moving a potentially unstable load that could lead to a perturbation, people tended to lift the container more slowly comparing with lifting a stable load, which in turn reduced the peak muscle activities. Application: In industry, there are many work situations where workers need to lift or carry unstable loads that can shift during transport. Providing visual access to the load may help mitigate some of these effects.


Author(s):  
Rahid Zaman ◽  
Yujiang Xiang ◽  
Jazmin Cruz ◽  
James Yang

In this study, the three-dimensional (3D) asymmetric maximum weight lifting is predicted using an inverse-dynamics-based optimization method considering dynamic joint torque limits. The dynamic joint torque limits are functions of joint angles and angular velocities, and imposed on the hip, knee, ankle, wrist, elbow, shoulder, and lumbar spine joints. The 3D model has 40 degrees of freedom (DOFs) including 34 physical revolute joints and 6 global joints. A multi-objective optimization (MOO) problem is solved by simultaneously maximizing box weight and minimizing the sum of joint torque squares. A total of 12 male subjects were recruited to conduct maximum weight box lifting using squat-lifting strategy. Finally, the predicted lifting motion, ground reaction forces, and maximum lifting weight are validated with the experimental data. The prediction results agree well with the experimental data and the model’s predictive capability is demonstrated. This is the first study that uses MOO to predict maximum lifting weight and 3D asymmetric lifting motion while considering dynamic joint torque limits. The proposed method has the potential to prevent individuals’ risk of injury for lifting.


1987 ◽  
Vol 31 (4) ◽  
pp. 462-466 ◽  
Author(s):  
Sean Gallagher ◽  
Richard L. Unger ◽  
E. William Rossi

The purpose of this study was to examine the lifting capacity of low-seam coal miners in four restricted work postures (roof heights of 36″, 40″, 44″, and 48″), investigate the associated metabolic costs, and to examine electromyographic (EMG) data from eight trunk muscles during the lifting procedure. Subjects were thirteen underground miners accustomed to handling materials in restricted work postures. Each subject performed two twenty-minute periods of asymmetric lifting in each of four postures during the day of testing. The frequency of lifting was 10 lifts per minute. A specially designed lifting box incorporated microswitches in one handle of the box and another in the bottom of the box, in order to examine the trunk muscle function at specific points during the lfting cycle. The data collected will be used by the Bureau of Mines to make recommendations for lifting materials in low-seam coal mines.


2001 ◽  
Vol 32 (6) ◽  
pp. 541-547 ◽  
Author(s):  
Thomas G. Bobick ◽  
Jean-Louis Belard ◽  
Hongwei Hsiao ◽  
James T. Wassell

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Narayan Yoganandan ◽  
Cameron R. Bass ◽  
Liming Voo ◽  
Frank A. Pintar

There is an increased need to develop female-specific injury criteria and anthropomorphic test devices (dummies) for military and automotive environments, especially as women take occupational roles traditionally reserved for men. Although some exhaustive reviews on the biomechanics and injuries of the human spine have appeared in clinical and bioengineering literatures, focus has been largely ignored on the difference between male and female cervical spine responses and characteristics. Current neck injury criteria for automotive dummies for assessing crashworthiness and occupant safety are obtained from animal and human cadaver experiments, computational modeling, and human volunteer studies. They are also used in the military. Since the average human female spines are smaller than average male spines, metrics specific to the female population may be derived using simple geometric scaling, based on the assumption that male and female spines are geometrically scalable. However, as described in this technical brief, studies have shown that the biomechanical responses between males and females do not obey strict geometric similitude. Anatomical differences in terms of the structural component geometry are also different between the two cervical spines. Postural, physiological, and motion responses under automotive scenarios are also different. This technical brief, focused on such nonuniform differences, underscores the need to conduct female spine-specific evaluations/experiments to derive injury criteria for this important group of the population.


2017 ◽  
Vol 37 (3) ◽  
pp. 611-618 ◽  
Author(s):  
Bin Yang ◽  
Zheng Shi ◽  
Qun Wang ◽  
Feng Xiao ◽  
Tong-Tong Gu ◽  
...  

This study is based on a real finite element human head–neck model and concentrates on its numerical vibration characteristic. Frequency spectrum and mode shapes of the finite element model of human head–neck under mechanical vibration have been calculated. These vibration characteristics are in good agreement with the previous studies. The simulated fundamental frequency of 35.25 Hz is fairly similar to the published documents, and rarely reported modal responses such as “mastication” and flipping of nasal lateral cartilages modes, however, are introduced by our three-dimensional modal analysis. These additional modes may be of interest to surgeons or clinicians who are specialized in temporomandibular or rhinoplasty joint disorder. Modal validation in terms of modal shapes proposes a necessity for elaborate modeling to identify each individual part’s extra frequencies. Furthermore, it also studies the influence of damping on resonant frequencies and biomechanical responses. It is discovered that damping has an inverse proportionality between damping effect on natural frequency and that on biomechanical responses.


2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Noor Arifah Azwani Abdul Yamin ◽  
Khairul Salleh Basaruddin ◽  
Ahmad Faizal Salleh ◽  
Mohammad Shahril Salim ◽  
Wan Zuki Azman Wan Muhamad

Objective. The aim of this study was to investigate the effects of surface stiffness on multisegment foot kinematics and temporal parameters during running. Methods. Eighteen male subjects ran on three different surfaces (i.e., concrete, artificial grass, and rubber) in both heeled running shoes (HS) and minimal running shoes (MS). Both these shoes had dissimilar sole profiles. The heeled shoes had a higher sole at the heel, a thick base, and arch support, whereas the minimal shoes had a flat base sole. Indeed, the studied biomechanical parameters responded differently in the different footwear during running. Subjects ran in recreational mode speed while 3D foot kinematics (i.e., joint rotation and peak medial longitudinal arch (MLA) angle) were determined using a motion capture system (Qualysis, Gothenburg, Sweden). Information on stance time and plantar fascia strain (PFS) was also collected. Results. Running on different surface stiffness was found to significantly affect the peak MLA angles and stance times for both HS and MS conditions. However, the results showed that the joint rotation angles were not sensitive to surface stiffness. Also, PFS showed no relationship with surface stiffness, as the results were varied as the surface stiffness was changed. Conclusion. The surface stiffness significantly contributed towards the effects of peak MLA angle and stance time. These findings may enhance the understanding of biomechanical responses on various running surfaces stiffness in different shoe conditions.


Ergonomics ◽  
1998 ◽  
Vol 41 (6) ◽  
pp. 817-834 ◽  
Author(s):  
WILLIAM S. MARRAS ◽  
KERMIT G. DAVIS
Keyword(s):  

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