A nonlinear dynamics of trunk kinematics during manual lifting tasks

Khalaf, Tamer M.; Karwowski, Waldemar; Sapkota, Nabin

doi:10.3233/wor-141880

Cited by 5 publications

(2 citation statements)

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“…The results of the muscle activities analysis indicated variable responses to the differences in workload intensity concerning the frequency of lifting and ambient oxygen content, both in combination with wearing the safety shoe type during different replications. This result suggests that different musculoskeletal system components followed different strategies in response to workload intensities, as recommended by Khalaf [80].…”

Section: Discussionmentioning

confidence: 69%

Effect of Ambient Oxygen Content, Safety Shoe Type, and Lifting Frequency on Subject’s MAWL and Physiological Responses

Ghaleb

Ramadan

Badwelan

et al. 2019

IJERPH

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Objective: The purpose of this study was to evaluate the lifting capabilities of individuals in hypoxia when they wear different types of safety shoes and to investigate the behavior of the physiological responses induced by the lifting process associated with those variables. Methods: An experimental design was used, based on two sessions. The first was training and acclimatization session, then an experimental lifting phase. A total of ten male students of King Saud University were recruited in the study. A four-way repeated measures design, with four independent variables and six dependent variables, was used in this research. The independent variables that were studied in the experimental lifting phase were: ambient oxygen content (15%, 18%, and 21%), safety shoes type (light-duty, medium-duty, and heavy-duty), lifting frequency (1 and 4 lifts/min), and replication (first and second trials). The dependent variables were also: maximum acceptable weights lifting using the psychophysical technique, heart rate (HR), electromyography (EMG) of (biceps brachii, trapezius, anterior deltoid, and erector spinae), safety shoes discomfort rating, rating of perceived exertion, and ambient oxygen discomfort rating. Results: The maximum acceptable weights lifting that were selected by participants at lower levels of the independent variables (ambient oxygen content 21%, lifting frequency 1 lift/min, and first replication) were significantly higher than at high levels of the independent variables (ambient oxygen content 15%, lifting frequency 4 lift/min, and second replication). Several interaction effects were also significant. Conclusions: It provides evidence that the ambient oxygen content increases the intensity of workload in lifting tasks. It showed that oxygen content affects the psychophysical selection of maximum acceptable weights lifting and the physiological responses represented in muscular activities and heart rate. It suggests that ambient oxygen content must be considered along with the type of safety shoes worn when the lifting task at altitudes occurs.

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Section: Discussionmentioning

confidence: 69%

Effect of Ambient Oxygen Content, Safety Shoe Type, and Lifting Frequency on Subject’s MAWL and Physiological Responses

Ghaleb

Ramadan

Badwelan

et al. 2019

IJERPH

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“…A key point, which is also neglected, is that repetitive lifting is a complex dynamic task (Chen, 2000) with nonlinear dynamical properties of biomechanical responses (Khalaf et al, 2015). Recent research evidence supports the fact that linear measures quantify the magnitude of variation in a series of data irrespective of their order in the distribution.…”

Section: Introductionmentioning

confidence: 99%

A Comprehensive Evaluation of Spine Kinematics, Kinetics, and Trunk Muscle Activities During Fatigue-Induced Repetitive Lifting

et al. 2021

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Objective Spine kinematics, kinetics, and trunk muscle activities were evaluated during different stages of a fatigue-induced symmetric lifting task over time. Background Due to neuromuscular adaptations, postural behaviors of workers during lifting tasks are affected by fatigue. Comprehensive aspects of these adaptations remain to be investigated. Method Eighteen volunteers repeatedly lifted a box until perceived exhaustion. Body center of mass (CoM), trunk and box kinematics, and feet center of pressure (CoP) were estimated by a motion capture system and force-plate. Electromyographic (EMG) signals of trunk/abdominal muscles were assessed using linear and nonlinear approaches. The L5-S1 compressive force (Fc) was predicted via a biomechanical model. A two-way multivariate analysis of variance (MANOVA) was performed to examine the effects of five blocks of lifting cycle (C1 to C5) and lifting trial (T1 to T5), as independent variables, on kinematic, kinetic, and EMG-related measures. Results Significant effects of lifting trial blocks were found for CoM and CoP shift in the anterior–posterior direction (respectively p < .001 and p = .014), trunk angle ( p = .004), vertical box displacement ( p < .001), and Fc ( p = .005). EMG parameters indicated muscular fatigue with the extent of changes being muscle-specific. Conclusion Results emphasized variations in most kinematics/kinetics, and EMG-based indices, which further provided insight into the lifting behavior adaptations under dynamic fatiguing conditions. Application Movement and muscle-related variables, to a large extent, determine the magnitude of spinal loading, which is associated with low back pain.

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Nonlinear dynamical systems for theory and research in ergonomics

Guastello

2016

Ergonomics

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Nonlinear dynamical systems (NDS) theory offers new constructs, methods and explanations for phenomena that have in turn produced new paradigms of thinking within several disciplines of the behavioural sciences. This article explores the recent developments of NDS as a paradigm in ergonomics. The exposition includes its basic axioms, the primary constructs from elementary dynamics and so-called complexity theory, an overview of its methods, and growing areas of application within ergonomics. The applications considered here include: psychophysics, iconic displays, control theory, cognitive workload and fatigue, occupational accidents, resilience of systems, team coordination and synchronisation in systems. Although these applications make use of different subsets of NDS constructs, several of them share the general principles of the complex adaptive system. Practitioner Summary: Nonlinear dynamical systems theory reframes problems in ergonomics that involve complex systems as they change over time. The leading applications to date include psychophysics, control theory, cognitive workload and fatigue, biomechanics, occupational accidents, resilience of systems, team coordination and synchronisation of system components.

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A nonlinear dynamics of trunk kinematics during manual lifting tasks

Abstract: The findings support the importance of accounting for nonlinear dynamical properties of biomechanical responses to lifting tasks.

Cited by 5 publications

References 0 publications

Effect of Ambient Oxygen Content, Safety Shoe Type, and Lifting Frequency on Subject’s MAWL and Physiological Responses

Effect of Ambient Oxygen Content, Safety Shoe Type, and Lifting Frequency on Subject’s MAWL and Physiological Responses

A Comprehensive Evaluation of Spine Kinematics, Kinetics, and Trunk Muscle Activities During Fatigue-Induced Repetitive Lifting

Nonlinear dynamical systems for theory and research in ergonomics

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