Biomechanics Commons^™

Disability Reduction Following A Lumbar Stabilization Exercise Program For Low Back Pain: Large Vs. Small Improvement Subgroup Analyses Of Physical And Psychological Variables, Christian Larivière, Richard Preuss, Marie-France Coutu, Michael J. Sullivan, Nicolas Roy, Sharon M. Henry

Études primaires

Background: Little is known about why patients with low back pain (LBP) respond differently to treatment, and more specifically, to a lumbar stabilization exercise program. As a first step toward answering this question, the present study evaluates how subgroups of patients who demonstrate large and small clinical improvements differ in terms of physical and psychological changes during treatment. Methods: Participants (n = 110) performed the exercise program (clinical sessions and home exercises) over eight weeks, with 100 retained at six-month follow-up. Physical measures (lumbar segmental instability, motor control impairments, range of motion, trunk muscle endurance and physical performance tests) were …

Mise Au Point Et Validation D’Une Approche Terrain De Prédiction Des Chargements Au Dos Basée Sur Des Données De Laboratoire, Alain Delisle, François Thénault, André Plamondon, Hakim Mecheri

Rapports de recherche scientifique

Les troubles musculosquelettiques (TMS) et particulièrement ceux au bas du dos affectent de nombreux travailleuses et travailleurs chaque année au Québec (Vézina et al., 2011). Le chargement mécanique au bas dos est reconnu comme un facteur de risque pouvant mener au développement de maux de dos, et la manutention de charges peut occasionner des chargements importants et répétés. La façon habituelle de quantifier le chargement au dos des individus est d’estimer le moment qui s’exerce à l’articulation lombo-sacrée (L5/S1). L’estimation de ce moment se fait généralement en laboratoire et nécessite la connaissance de la position et de l’orientation de …

Analyse Du Concept De Marge De Manœuvre En Ergonomie Du Point De Vue Du Contrôle De La Motricité Humaine, Philippe Corbeil, André Plamondon, Denys Denis

Rapports de recherche scientifique

Le concept de marge de manœuvre se définit comme la liberté dont dispose un travailleur pour élaborer différentes façons de travailler afin de répondre aux exigences de production, et ce, sans effet défavorable sur sa santé (Coutarel, Caroly, Vézina et Daniellou, 2015; St-Vincent et al., 2011). Une forte charge de travail jumelée à une faible latitude décisionnelle restreint l’élaboration des gestes et pourrait pénaliser ainsi la santé des opérateurs. Les connaissances actuelles des façons de faire des manutentionnaires, qu’ils soient experts ou non, ne nous permettent pas d’apprécier dans sa totalité l’ampleur de cette liberté lorsqu’un individu doit répéter …

Submaximal Electromyography-Driven Musculoskeletal Modeling Of The Human Trunk During Static Tasks: Equilibrium And Stability Analyses, Farshid Ghezelbash, Aboulfazl Shirazi-Adl, Denis Gagnon, Ali Shahvarpour, Navid Arjmand, Amir Hossein Eskandari, Christian Larivière

Études primaires

Conventional electromyography-driven (EMG) musculoskeletal models are calibrated during maximum voluntary contraction (MVC) tasks, but individuals with low back pain cannot perform unbiased MVCs. To address this issue, EMG-driven models can be calibrated in submaximal tasks. However, the effects of maximal (when data points include the maximum contraction) and submaximal calibration techniques on model outputs (e.g., muscle forces, spinal loads) remain yet unknown. We calibrated a subject-specific EMG-driven model, using maximal/submaximal isometric contractions, and simulated different independent tasks. Both approaches satisfactorily predicted external moments (Pearson’s correlation ∼ 0.75; relative error = 44%), and removing calibration tasks under axial torques markedly improved …

Développement D’Un Outil Personnalisé D’Aide À La Décision En Vue De Minimiser Les Risques En Manutention Impliquant Des Postures Symétriques Et Asymétriques, Aboulfazl Shirazi-Adl, Navid Arjmand, André Plamondon

Rapports de recherche scientifique

Les charges excessives imposées sur la colonne vertébrale lombaire constituent un facteur de risques important pour les maux de dos. La modélisation biomécanique de la colonne vertébrale est la seule approche non invasive permettant d’estimer ces charges, mais la complexité de ces modèles limite leur utilisation par des ergonomes. Pour aider ces derniers à identifier des situations à risque de blessures au dos afin de limiter le chargement aux structures lombaires, il existe des outils d’aide à la décision comme l’équation de levage du NIOSH (Revised NIOSH Lifting Equation, Waters et al., 1993) ainsi que les tables …

Structural Remodeling Of The Lumbar Multifidus, Thoracolumbar Fascia And Lateral Abdominal Wall Perimuscular Connective Tissues: A Search For Its Potential Determinants, Christian Larivière, Sharon M. Henry, Richard Preuss

Études primaires

Recently remodeling of lumbar soft tissues has received increased research attention. However, the major determinants that influence remodeling need to be elucidated in order to understand the impact of different rehabilitation modalities on tissue remodeling. The main aim of this study was to explore the between-subject variance of different measures of lumbar soft tissues quantified with rehabilitative ultrasound imaging (RUSI). RUSI measures (n = 8) were collected from 30 subjects without and 34 patients with LBP: (1) lumbar multifidus (LM) echogenicity (fatty infiltration/fibrosis) at three vertebral levels (L3/L4, L4/L5 and L5/S1) (n = 3); (2) posterior layer thickness …

The Effect Of Extensible And Non-Extensible Lumbosacral Orthoses On Anticipatory Postural Adjustments In Participants With Low Back Pain And Healthy Controls, Christian Larivière, Richard Preuss

Études primaires

Background

Wearing a lumbosacral orthosis (LSO) is known to influence spine mechanics, but less is known about how LSOs affect motor control. Whether the use of a LSO can negatively affect motor control of the lumbar spine is still under debate.

Objective

The current study examined the immediate effects of two flexible LSOs (extensible and non-extensible) on the anticipatory postural adjustments that prepare the spine for a predictable perturbation.

Design

A comparative study using a repeated measures design in a laboratory setting.

Methods

Healthy controls (n = 20) and participants with low back pain (n = 40) performed a rapid …

Is Postural Control During Unstable Sitting A Proxy Measure For Determinants Associated With Lumbar Stability?, Christian Larivière, Richard Preuss, Daniel Ludvig, Sharon M. Henry

Études primaires

Abstract

The aim of this study was to test whether determinants associated with lumbar stability can predict performance during unstable sitting (trunk postural control - TPC). If confirmed, unstable sitting could be viewed as a proxy measure for these determinants. Wobbling chair motion was measured in 58 subjects with an inertial sensor, and six outcomes were computed (mean frequency and velocity, frequency dispersion, two variables from the sway density analysis and Lyapunov exponent - short interval) to represent TPC performance. Subjects also performed five other trunk neuromuscular tests to quantify the thickness of back and abdominal muscles and …

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 …

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 …

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 …

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: …

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 …

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 …

Effects Of Footstrike Pattern On Low Back Posture, Shock Attenuation, And Comfort During Running, Traci L. Delgado, Emilia Kubera-Shelton, Robert R. Robb

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: Barefoot running (BF) is popular in the running community. Biomechanical changes occur with BF, especially when initial contact changes from rearfoot strike (RFS) to forefoot strike (FFS). In addition, changes in lumbar spine range of motion (ROM), particularly involving lumbar lordosis, have been associated with increased low back pain (LBP). However it is not known how changing from RFS to FFS affects lumbar lordosis or LBP. Thus, the purpose of this study was to determine if a change from RFS to FFS would change lumbar lordosis, and/or decrease shock attenuation, and/or change comfort levels in healthy recreational/experienced runners.

Methods: …

The Effect Of Floor Sitting Posture On Low-Back Pain, Knee Pain And Hip Pain Among Kuwaiti Men, Sameera H. Al-Jedi

Rehabilitation Sciences Theses & Dissertations

Background and Purpose. Ground resting posture is common in Kuwait and other Arab communities. Kuwaiti men gather daily, especially on weekend nights socializing in the Diwaniya. Diwaniya is a special room in every Kuwaiti house. The Diwaniya is traditionally furnished with seating cushions and pillows. Men are seated on the floor in a tailor-sitting posture for long periods of time. The tailor-sitting posture flexes the trunk. hips, and knees. The flexion position has been shown to decrease the lumbar lordosis and increase joint compression in hips and knees. However there are no studies about the effect of floor sitting …