Occupational Health and Industrial Hygiene Commons^™

Structural Remodelling Of The Lumbar Multifidus, Thoracolumbar Fascia And Lateral Abdominal Wall Perimuscular Connective Tissues: A Cross-Sectional And Comparative Ultrasound Study, Christian Larivière, Richard Preuss, Dany H. Gagnon, Hakim Mecheri, Sharon M. Henry

Études primaires

Introduction

With low back pain (LBP), remodelling of the lumbar soft tissues involves both trunk muscles and neighbouring passive connective tissues. The aim of the present study was to compare three quantitative measures of these tissues, using ultrasound imaging (USI), among healthy controls and individuals with LBP.

Methods

USI measures from 30 healthy subjects and 34 patients with non-acute LBP were compared between groups and sexes. The measures employed were (1) lumbar multifidus echogenicity (fatty/fibrosis infiltration) at three vertebral levels; (2) posterior layer thickness of the thoracolumbar fascia, and (3) thickness of the perimuscular tissues surrounding the external oblique, internal …

Validation Of A Low-Cost Inertial Motion Capture System For Whole-Body Motion Analysis, X. Robert-Lachaine, H. Mecheri, A. Muller, C. Larue, A. Plamondon

Études primaires

While some low-cost inertial motion capture (IMC) systems are now commercially available, generally, they have not been evaluated against gold standard optical motion capture (OMC). The objective was to validate the low-cost Neuron IMC system with OMC. Whole-body kinematics were recorded on five healthy subjects during manual handling of boxes for about 32 min while wearing 17 magnetic and inertial measurement units with Optotrak clusters serving as a reference. The kinematical model was calibrated anatomically for OMC and with poses for IMC. Local coordinate systems were aligned with angular velocities to dissociate differences due to technology or kinematical model. Descriptive …

Feasibility Of Quantifying The Physical Exposure Of Materials Handlers In The Workplace With Magnetic And Inertial Measurement Units, Xavier Robert-Lachaine, Christian Larue, Denys Denis, Alain Delisle, Hakim Mecheri, Philippe Corbeil, André Plamondon

Études primaires

Handling tasks can expose workers to risk factors. The objective was to describe the feasibility of using magnetic and inertial measurement units (MIMUs) to quantify the physical exposure of materials handlers in the workplace. Full-body kinematics were obtained with MIMUs on 10 handlers gathering products ordered by retailers with a pallet truck. An observer classified the visual difference (VD) of segment orientation between a MIMUs avatar and video recordings in three categories (none, minor and major) for each product transfer. The feet, arms, shoulders and head were considered similar for ≥97% of observations. The trunk segment obtained the most differences …

Revisiting The Effect Of Manipulating Lumbar Stability With Load Magnitudes And Positions: The Effect Of Sex On Trunk Muscle Activation, Christian Larivière, Ali Shahvarpour, Christina Gravel, Myriam Gauvin, Anne-Marie Jean, Ariane Viau, Hakim Mecheri

Études primaires

Background

Lumbar spine stability is regularly studied by positioning different loads at different heights and distance and measuring trunk muscle activation changes. Some of these studies have reported sex differences, but this needs to be revisited while controlling for confounding factors.

Method

20 males and 20 females sustained three static standing postures, with various loads (0, 5 and 10% of body weight), to evaluate the effect of height and distance. Activation of 12 trunk muscles was recorded with surface electromyography (EMG).

Results

Females activated their external obliques a little more than males, with increases ranging between 1.5 and 2.3% of …

Vers Une Stratégie Intégrée De Prévention En Manutention : Document De Sensibilisation À La Prévention Des Troubles Musculosquelettiques (Tms) Reliés À Des Tâches De Manutention, Denys Denis, Edith Vinet

Guides

Destiné à tous les intervenants et les milieux de travail préoccupés par la prévention des troubles musculosquelettiques (TMS) reliés à des tâches de manutention, ce document propose une stratégie intégrée de prévention en manutention.

Combinant formation et intervention, cette stratégie repose sur la compréhension, l’observation et l’analyse de cinq principes d’action. Ces principes d’action sont les points communs de l’ensemble des techniques de manutention qu’utilisent les travailleurs. Chacun d’eux possède des repères d’observation caractéristiques. Les repères indiquent ainsi les compromis que le travailleur doit faire pour atteindre son objectif de préserver sa santé et sa sécurité, puisqu’ils sont liés aux …

Ultrasound Measures Of The Abdominal Wall In Patients With Low Back Pain Before And After An 8-Week Lumbar Stabilization Exercise Program, And Their Association With Clinical Outcomes, Christian Larivière, Sharon M. Henry, Dany H. Gagnon, Richard Preuss, Jean-Pierre Dumas

Études primaires

Background

Lumbar stabilization exercise programs (LSEPs) act positively on clinical outcome measures in patients with low back pain (LBP), but the underlying mechanisms are not well understood. Among the various neuromuscular mechanisms, a good candidate is better activation of the abdominal wall, as measured with rehabilitative ultrasound imaging (RUSI).

Objectives

To determine whether RUSI measures are (1) sensitive to LBP status and treatment (LSEP) and (2) correlate with clinical outcomes following the LSEP.

Design

An exploratory one-arm clinical trial with healthy participants as a control group.

Setting

LSEP was delivered in a clinical setting; outcomes were measured in a laboratory …

A Comparison Of Lumbar Spine And Muscle Loading Between Male And Female Workers During Box Transfers, Denis Gagnon, André Plamondon, Christian Larivière

Études primaires

There is a clear relationship between lumbar spine loading and back musculoskeletal disorders in manual materials handling. The incidence of back disorders is greater in women than men, and for similar work demands females are functioning closer to their physiological limit. It is crucial to study loading on the spine musculoskeletal system with actual handlers, including females, to better understand the risk of back disorders. Extrapolation from biomechanical studies conducted on unexperienced subjects (mainly males) might not be applicable to actual female workers. For male workers, expertise changes the lumbar spine flexion, passive spine resistance, and active/passive muscle forces. However, …

Trunk Postural Balance And Low Back Pain: Reliability And Relationship With Clinical Changes Following A Lumbar Stabilization Exercise Program, Ali Shahvarpour, Dany H. Gagnon, Richard Preuss, Sharon M. Henry, Christian Larivière

Études primaires

Lumbar stabilization programs reduce pain and disability, but the mechanisms of action underlying this treatment are unknown. Trunk postural control during unstable sitting represents a surrogate measure of motor control mechanisms involved to maintain the dynamic stability of the spine. This exploratory study aimed to determine the reliability of trunk postural control measures over an 8-week interval, their sensitivity to low back pain status and treatment and their relationship with clinical outcomes. Trunk postural control measures were determined in patients with low back pain before and after an 8-week lumbar stabilization exercise program. Healthy controls were assessed over the same …

The Effect Of Wearing A Lumbar Belt On Biomechanical And Psychological Outcomes Related To Maximal Flexion-Extension Motion And Manual Material Handling, Ali Shahvarpour, Richard Preuss, Michael J.L. Sullivan, Alessia Negrini, Christian Larivière

Études primaires

Workers with low back pain (LBP) may benefit from wearing a lumbar belt (LB), but the biomechanical and psychological mechanisms involved are not fully understood. Two types of flexible LB (extensible and non-extensible) were compared to a control condition (no LB) regarding pain-related (pain, fear of pain and catastrophizing) and biomechanical (range of motion – ROM) outcomes related to two tasks: maximal trunk flexion-extension and manual material handling. Healthy controls and participants with LBP were tested. During both tasks, the two LBs reduced the lumbar ROM in participants with LBP in the same way as healthy controls. This was observed …

An Analysis Of The Physiological And Psychological Wellbeing Of Irish Naval Service Personnel, Cliodhna Sargent

Theses

Whilst all military cohorts have been seen to experience both physiological and psychological stressors during occupational duties, the naval service experience different stressors due the prolonged periods of time spent at sea. Research has analysed some of these stressors however many them have focused on how individuals are affected because of time spent in combat zones. The Irish Naval Service (INS) is an organisation under the Irish Defence Forces organisation and as such many of its physiological and psychological assessment procedures have come from the Defenee Forces. Very limited researeh has been carried out in relation to the INS as …

Accuracy And Repeatability Of Single-Pose Calibration Of Inertial Measurement Units For Whole-Body Motion Analysis, Xavier Robert-Lachaine, Hakim Mecheri, Christian Larue, André Plamondon

Études primaires

Portable inertial measurement units (IMUs) are suitable for motion analysis outside the laboratory. However, IMUs depend on the calibration of each body segment to measure human movement. Different calibration approaches have been developed for simplicity of use or similarity to laboratory motion analysis, but they have not been extensively examined. The main objective of the study was to determine the accuracy and repeatability of two common single-pose calibrations (N-pose and T-pose) under different conditions of placement (self-placement and passive placement), as well as their similarity to laboratory analysis based on anatomical landmarks. A further aim of the study was to …

Difference Between Male And Female Workers Lifting The Same Relative Load When Palletizing Boxes, André Plamondon, Christian Larivière, Denys Denis, Hakim Mecheri, Iuliana Nastasia

Études primaires

A few biomechanical studies have contrasted the work techniques of female and male workers during manual material handling (MMH). A recent study showed that female workers differed from males mostly in the strategy they used to lift 15-kg boxes from the ground, especially regarding task duration, knee and back postures and interjoint coordination. However, the lifting technique difference observed in females compared to males was perhaps due to a strength differences. The objective of this study was to test whether female workers would repeat the same lifting technique with a load adjusted to their overall strength (females: 10 kg; males: …

Effect Of Local Magnetic Field Disturbances On Inertial Measurement Units Accuracy, Xavier Robert-Lachaine, Hakim Mecheri, Christian Larue, André Plamondon

Études primaires

Inertial measurement units (IMUs), a practical motion analysis technology for field acquisition, have magnetometers to improve segment orientation estimation. However, sensitivity to magnetic disturbances can affect their accuracy. The objective of this study was to determine the joint angles accuracy of IMUs under different timing of magnetic disturbances of various durations and to evaluate a few correction methods. Kinematics from 12 individuals were obtained simultaneously with an Xsens system where an Optotrak cluster acting as the reference system was affixed to each IMU. A handling task was executed under normal laboratory conditions and imposed magnetic disturbances. Joint angle RMSE was …

The Effect Of An 8-Week Stabilization Exercise Program On The Lumbopelvic Rhythm And Flexion-Relaxation Phenomenon, Ali Shahvarpour, Sharon M. Henry, Richard Preuss, Hakim Mecheri, Christian Larivière

Études primaires

Background

Lumbar stabilization exercise programs should normalize the aberrant movements patterns often observed in patients with low back pain. This study aimed to determine the effect of an 8-week lumbar stabilization program on EMG/kinematics measures of the aberrant movement patterns in such patients. A secondary goal was to assess the 8-week test-retest reliability of these measures.

Methods

The patients followed an 8-week lumbar stabilization program while no intervention was carried out on the controls. Before and after this period, kinematics of the spine along with the EMG of paraspinal muscles were recorded during trunk maximal flexion-extension. ANOVAs tested the effect …

Validation Of Inertial Measurement Units With An Optoelectronic System For Whole-Body Motion Analysis, Xavier Robert-Lachaine, Hakim Mecheri, Christian Larue, André Plamondon

Études primaires

The potential of inertial measurement units (IMUs) for ergonomics applications appears promising. However, previous IMUs validation studies have been incomplete regarding aspects of joints analysed, complexity of movements and duration of trials. The objective was to determine the technological error and biomechanical model differences between IMUs and an optoelectronic system and evaluate the effect of task complexity and duration. Whole-body kinematics from 12 participants was recorded simultaneously with a full-body Xsens system where an Optotrak cluster was fixed on every IMU. Short functional movements and long manual material handling tasks were performed and joint angles were compared between the two …

Obesity And Obesity Shape Markedly Influence Spine Biomechanics: A Subject-Specific Risk Assessment Model, Farshid Ghezelbash, Aboulfazl Shirazi-Adl, André Plamondon, Navid Arjmand, Mohammad Parnianpour

Études primaires

Underlying mechanisms of obesity-related back pain remain unexplored. Thus, we aim to determine the effect of obesity and its shapes on the spinal loads and the associated risks of injury. Obesity shapes were initially constructed by principal component analysis based on datasets on 5852 obese individuals. Spinal loads, cycles to vertebral failure and trunk stability margin were estimated in a subject-specific trunk model taking account of personalized musculature, passive ligamentous spine, obesity shapes, segmental weights, spine kinematics and bone mineral density. Three obesity shapes (mean and extreme abdominal circumferences) at three body weights (BWs) of 86, 98 and 109 kg …

A Biomechanical Comparison Between Expert And Novice Manual Materials Handlers Using A Multi-Joint Emg-Assisted Optimization Musculoskeletal Model Of The Lumbar Spine, Denis Gagnon, André Plamondon, Christian Larivière

Études primaires

Expertise is a key factor modulating the risk of low back disorders (LBD). Through years of practice in the workplace, the typical expert acquires high level specific skills and maintains a clean record of work-related injuries. Ergonomic observations of manual materials handling (MMH) tasks show that expert techniques differ from those of novices, leading to the idea that expert techniques are safer. Biomechanical studies of MMH tasks performed by experts/novices report mixed results for kinematic/kinetic variables, evoking potential internal effect of expertise. In the context of series of box transfers simulated by actual workers, detailed internal loads predicted by a …

Subject-Specific Biomechanics Of Trunk: Musculoskeletal Scaling, Internal Loads And Intradiscal Pressure Estimation, F. Ghezelbash, A. Shirazi-Adl, N. Arjmand, Z. El-Ouaaid, A. Plamondon

Études primaires

Development of a subject-specific computational musculoskeletal trunk model (accounting for age, sex, body weight and body height), estimation of muscle forces and internal loads as well as subsequent validation by comparison with measured intradiscal pressure in various lifting tasks are novel, important and challenging. The objective of the present study is twofold. First, it aims to update and personalize the passive and active structures in an existing musculoskeletal kinematics-driven finite element model. The scaling scheme used an existing imaging database and biomechanical principles to adjust muscle geometries/cross-sectional-areas and passive joint geometry/properties in accordance with subjects’ sex, age, body weight and …

Effects Of Sex, Age, Body Height And Body Weight On Spinal Loads: Sensitivity Analyses In A Subject-Specific Trunk Musculoskeletal Model, F. Ghezelbash, A. Shirazi-Adl, N. Arjmand, Z. El-Ouaaid, A. Plamondon, J. R. Meakin

Études primaires

Subject-specific parameters influence spinal loads and the risk of back disorders but their relative effects are not well understood. The objective of this study is to investigate the effects of changes in age (35–60 years), sex (male, female), body height (BH: 150–190 cm) and body weight (BW: 50–120 kg) on spinal loads in a full-factorial simulation using a personalized (spine kinematics, geometry, musculature and passive properties) kinematics driven musculoskeletal trunk finite element model. Segmental weight distribution (magnitude and location along the trunk) was estimated by a novel technique to accurately represent obesity. Five symmetric sagittal loading conditions were considered, and …

Trunk Postural Control In Unstable Sitting: Effect Of Sex And Low Back Pain Status, Christian Larivière, Dany H. Gagnon, Hakim Mecheri

Études primaires

Background

Adequate neuromuscular control of the lumbar spine is required to prevent lumbar injuries. A trunk postural control test protocol, controlling for the influence of body size on performance, was implemented to carry out between-subject comparisons. The aim of this study was to assess the effect of sex and low back pain status with the use of two measures of trunk postural control, the first based on chair motion, and the second based on trunk motion.

Methods

Thirty-six subjects (with and without low back pain) performed three 60-s trunk postural control trials with their eyes closed while seated on an …

Identification Of Intrinsic And Reflexive Contributions To Low-Back Stiffness: Medium-Term Reliability And Construct Validity, Christian Lariviere, Daniel Ludvig, Robert Kearney, Hakim Mecheri, Jean-Maxime Caron, Richard Preuss

Études primaires

This study aimed at testing the reliability and construct validity of a trunk perturbation protocol (TPP) that estimates the intrinsic and reflexive contributions to low-back stiffness. The TPP consists of a series of pseudorandom position-controlled trunk perturbations in an apparatus measuring forces and displacements at the harness surrounding the thorax. Intrinsic and reflexive contributions to low-back stiffness were estimated using a system identification procedure, leading to 12 parameters. Study 1 methods (reliability): 30 subjects performed five 75- s trials, on each of two separate days (eight weeks apart). Reliability was assessed using the generalizability theory, which allowed computing indexes of …

Beyond Basic Exercise Guidelines: Is Sitting Really The New Smoking?, Mary Stenson

Forum Lectures

The "Just Stand" movement has recently gained a foothold at CSB|SJU with the addition of sit-stand workstations in Clemens Library, Murray Hall, and several faculty and staff offices. Researchers have been studying "sitting disease," more formally termed sedentary physiology, for over a decade and have begun to conclude that simply meeting exercise guidelines is not enough to reduce risk for chronic diseases. An individual can be physically active and lead a sedentary lifestyle. The two are not mutually exclusive. The average American adult, even those who meet the general exercise guidelines, spends 55% of their waking hours sedentary. Sedentary behaviors …

Physical Fitness Characteristics Of An Active Firefighter Population Serving An Urban Area, Michael R. Antolini

Theses and Dissertations (Comprehensive)

Firefighters require a high level of physical fitness in order to meet the demands of their profession. While physical fitness testing is required to join the department, firefighters are not subject to further formal exercise testing throughout the duration of their careers. Active, career firefighters were tested on a variety of physical fitness measures related to body composition, strength, power, and endurance over three testing sessions. 49 firefighters (40.5 ± 8.3 yr, 89.5 ± 13.0 kg, 27.8 ± 3.6 kg/m2) were found to have a resting heart rate of 57.7 ± 8.2 bpm, blood pressure of 121.5 ± 11.9/71.5 ± …

Firefighter Fitness-For-Duty Medical Screening: A Peer Review Quality Improvement Pilot, Julie Collings Rochefort

UNLV Theses, Dissertations, Professional Papers, and Capstones

Despite the overwhelming evidence that sudden cardiac death is the most frequent cause of firefighter fatalities, many fire departments do not have a program to measure or maintain basic firefighter fitness and health. This project evaluated and compared medical screening outcomes of four industrial fire brigades within a multinational oil and gas corporation and introduced a quality improvement plan. The goal of this project was to apply the evidence and measure outcomes to determine the most effective way to ensure that firefighters in a corporate setting are healthy. This was accomplished by utilizing established guidelines in developing an educational program …

Effect Of A Work Site Exercise Program On Selected Fitness And Psychological Parameters, Kristen Ann Christiansen

UNLV Theses, Dissertations, Professional Papers, and Capstones

The increasing rates of obesity continue to threaten the vitality of our nation. Health care costs are soaring and chronic diseases are reaching even the youngest populations. Physical activity is an integral component in reversing the obesity epidemic and improving the health of today's workforce. The present study sought to determine the effect of a work site exercise program on select fitness and psychological parameters. Five female employees participated in a six-week exercise program utilizing HealthBeat(TM) outdoor exercise equipment in a circuit fashion for 30 minutes, 2 days per week. Eighty percent of participants were categorized as sedentary or low-active …