Occupational Health and Industrial Hygiene Commons^™

How Effective Is The Filtration Of ‘Kn95’ Filtering Facepiece Respirators During The Covid-19 Pandemic?, Clothilde Brochot, Mohamed Nejib Saidi, Ali Bahloul

Études primaires

Objectives

The high demand of filtering facepiece respirators (FFRs) worldwide during the period of the COVID-19 pandemic has led to a critical situation for decision-makers regarding their supply. After authorizing the use of FFRs certified by other regions of the world, decision-makers in many countries have published alerts, particularly concerning the ‘KN95’ type.

Methods

This paper investigated the filtration performance of different FFRs using an experimental setup already employed during several studies on FFRs filtration performance. Its high-resolution measuring devices permit to determine filtration performance according to the normative criteria: the pressure drop and the filtration efficiency. Eight different FFRs …

Numerical Investigation Of The Earplug Contribution To The Low-Frequency Objective Occlusion Effect Induced By Bone-Conducted Stimulation, Kevin Carillo, Olivier Doutres, Franck Sgard

Études primaires

The use of earplugs is commonly associated with an increased perception of the bone-conducted part of one's own physiological noise. This phenomenon is referred to as occlusion effect and is most prominent at low frequencies. Several factors influence the occlusion effect, such as the ear anatomy; the bone-conducted stimulation; and the type of occlusion device and its fit, insertion depth, and material properties. The latter factor is of great interest to potentially reduce the occlusion effect of passive earplugs. This paper investigates the mechanism(s) of contribution of earplugs to the objective occlusion effect. A two-dimensional axi-symmetric finite element model of …

New Taxonomy For Assessing Manual Material Handlers’ Footstep Patterns, Jasmin Vallée-Marcotte, Antoine Muller, Xavier Robert-Lachaine, Véronique Fecteau, Denys Denis, André Plamondon, Philippe Corbeil

Études primaires

Current taxonomies for assessing foot strategies in manual material handling lack exhaustive classification of foot movements and foot positioning. They also fail to consider different instants of the task as checkpoints to relate foot strategies. The goal of the study was first to develop a new taxonomy to assess foot positions and motions considering those limitations. The second goal was to assess reliability and reproducibility using raw agreement percentages, Cohen's kappa, prevalence-adjusted, bias-adjusted kappa and Gwet's AC1. A filmed task consisted of transferring boxes from one pallet to another. Intra- and inter-rater reliability were assessed reviewing 23% and 10%, respectively, …

Simulation Of The Objective Occlusion Effect Induced By Bone-Conducted Stimulation Using A Three-Dimensional Finite-Element Model Of A Human Head, Huiyang Xu, Franck Sgard, Kévin Carillo, Éric Wagnac, Jacques De Guise

Études primaires

The occlusion effect (OE) refers to the phenomenon that more bone-conducted physiological sounds are transmitted into the earcanal when it is blocked and may cause discomfort on users of hearing protection devices. Models have been proposed to study the OE as they can help understand the physical mechanisms and can be used to evaluate the individual contribution on the OE of the factors that may affect it (i.e., occlusion device, ear anatomy, and stimulation). The existing finite element models developed to study the OE are limited by their truncated ear geometries. In order to progress in the understanding of the …

Assessing The Comfort Of Earplugs: Development And Validation Of The French Version Of The Coprod Questionnaire, Jonathan Terroir, Nellie Perrin, Pascal Wild, Olivier Doutres, Franck Sgard, Chantal Gauvin, Alessia Negrini

Études primaires

Earplugs are a common form of protection for workers exposed to hazardous noise levels. Their comfort directly impacts the effective protection by influencing their consistent and correct use. Nevertheless, comfort definition may vary according to the studies. Thus, a previous review of the literature has shown that to improve our understanding of perceived comfort and to reduce measurement variability, it is advisable to consider comfort through a multidimensional construct (physical, acoustical, functional and psychological). On this basis, the COPROD (COnfort des PROtections auDitives/COmfort of hearing PROtection Devices) questionnaire was developed. It is intended for people working in noisy environments. Nine …

Combined Puncture And Cutting Of Soft-Coated Fabrics By A Pointed Blade: Energy, Force, And Stress Failure Criteria, Ennouri Triki, Chantal Gauvin

Études primaires

Soft elastomer-coated fabrics are widely used in engineering and protective applications. Puncture cutting by sharp-tipped objects is one of the most common failure modes of protective gloves made of coated fabrics. In order to investigate the puncture-cutting process of soft elastomer-coated fabrics, we studied the mechanisms and mechanics of pointed-blade insertion into specimens cut out from four protective gloves. Experimental and analytical analyses showed that total energy and critical puncture-cutting force calculated analytically are both able to predict the puncture-cutting resistance of soft elastomer-coated fabrics measured experimentally. Total energy is obtained from the relationship between the puncture-cutting work and the …

Development And Characterization Of An Adaptable Aerosolized Methylene Diphenyl Diisocyanate Generation System, Simon Aubin, Loïc Wingert, Sébastien Gagné, Livain Breau, Jacques Lesage

Études primaires

Reactive semivolatile contaminants, such as isocyanates, can be particularly difficult to assess in occupational environments. While standard methods exist for isocyanates, there are still significant differences between the results they provide for various occupational environments or processes. This study presents the validation of a laboratory system for the generation of controlled atmospheres of isocyanates. A system consisting of different modules generated airborne methylene diphenyl diisocyanate (MDI) by nebulizing a solution into mixing and exposure chambers with control of flow rate, temperature, and relative humidity. Sampling was performed through an eight-port flow splitter that allowed only very slight within-test variability. MDI …

Effect Of Hearing And Head Protection On The Localization Of Tonal And Broadband Reverse Alarms, Chantal Laroche, Christian Giguère, Véronique Vaillancourt, Claudia Marleau, Marie-France Cadieux, Karina Laprise-Girard, Emily Gula, Véronique Carroll, Manuelle Bibeau, Hugues Nélisse

Études primaires

Objective

This study explored the effects of hearing protection devices (HPDs) and head protection on the ability of normal-hearing individuals to localize reverse alarms in background noise.

Background

Among factors potentially contributing to accidents involving heavy vehicles, reverse alarms can be difficult to localize in space, leading to errors in identifying the source of danger. Previous studies have shown that traditional tonal alarms are more difficult to localize than broadband alarms. In addition, HPDs and safety helmets may further impair localization.

Method

Standing in the middle of an array of eight loudspeakers, participants with and without HPDs (passive and level-dependent) …

Safety In The Quebec Construction Industry: An Overview Of And Possible Improvements In Hazardous Energy Control Using Lockout On Construction Sites By Electricians, Pipefitters, Refrigeration Mechanics And Construction Millwrights, Damien Burlet-Vienney, Yuvin Chinniah, Ayoub Nokra, Abdallah Ben Mosbah

Études primaires

Lack of proper energy control on construction sites leads to numerous worker fatalities every year. Energy control refers to the concept of lockout and other methods used in particular in North America. The aim of this exploratory research project was to achieve a better understanding of energy control practices in the Quebec construction industry for four trades: electricians, pipefitters, refrigeration mechanics and construction millwrights. For each trade, 10 or so semistructured interviews were conducted by means of an open-ended questionnaire, developed with reference to the current provincial regulatory requirements. The 95 experiences described by the 38 participants were compiled by …

Comparative Performance Of The Nanoscan And The Classic Smps In Determining N95 Filtering Facepiece Efficiency Against Nanoparticles, Clothilde Brochot, Fariborz Haghighat, Ali Bahloul

Études primaires

Nanoparticles are defined as particles with at least one dimension in the range of 1–100 nm. Due to the special properties of nanoparticles, they are used in many workplaces, thus leading to occupational exposure. Filtering facepieces (FFPs) are generally used in these workplaces to reduce the exposure. Many studies have measured FFP efficiency in laboratories using a scanning mobility particle sizer (SMPS). The aim of this study was to determine whether a NanoScan could be used to measure FFP efficiency against nanoparticles in workplaces for one type of N95 FFP. The results showed that the NanoScan gave maximum penetration and …

Adherence To A Home Exercise Programme Following A Clinical Programme For Non-Acute Non-Specific Low Back Pain: An Exploratory Study, Judith L'Heureux, Marie-France Coutu, Djamal Berbiche, Christian Larivière

Études primaires

Purpose:Lack of adherence to home exercise programmes is hypothesised to partially explain the modest clinical effects seen in patients with low back pain. This study explored the association between the main biopsychosocial factors and adherence using a theory-driven approach including the fear-avoidance model, the common-sense model and the working alliance concept.

Methods: A repeated measures design was used. During and after an eight-week clinical exercise programme, 48 participants with non-acute and disabling low back pain followed a home exercise programme. Questionnaires assessed home exercise adherence and biopsychosocial factors at baseline, after the eight-week clinical programme and at the six-month follow-up. …

On Site Comparison Of The Osha 42, Asset Ez4-Nco, Iso-Chek, Dan And Cip10 Methods For Measuring Toluene Diisocyanate (Tdi) At A Polyurethane Foam Factory, Simon Aubin, El Mekki Hamdi, Audrey Joly, Philippe Sarazin, Jacques Lesage, Livain Breau, Mark Spence, Sébastien Gagné

Études primaires

Because of the semi-volatile nature of diisocyanates (being airborne in both physical vapor and particulate phases), their high reactivity and low occupational exposure limits, diisocyanate exposure evaluation has been challenging for industrial hygienists and laboratories. The objective of this study was to compare the toluene diisocyanate (2,4 and 2,6 isomers, TDI) concentration measured by five methods in a flexible polyurethane foam factory using different collection or derivatization approaches. The methods used were: OSHA 42 modified (filter, 1-(2-pyridyl)piperazine) (OSHA), Asset EZ4-NCO (denuder and filter, dibutylamine) (Asset), Iso-Chek (double-filter, 9-(N-methylaminomethyl) anthracene and 1,2-methoxyphenylpiperazine), DAN (filter, 1,8-diaminonaphthalene), and CIP10 (centrifugation, 1,2-methoxyphenylpiperazine). Particle real-time …

Three-Month Efficacy Of Three Knee Braces In The Treatment Of Medial Knee Osteoarthritis In A Randomized Crossover Trial, Xavier Robert-Lachaine, Yoann Dessery, Étienne L. Belzile, Sylvie Turmel, Philippe Corbeil

Études primaires

Immediate biomechanical and functional effects of knee braces are often reported, however, the duration and type of knee brace treatment for knee osteoarthritis (KOA) remain unclear. The objective was to evaluate usage, comfort, pain, and knee adduction moment (KAM) of three knee braces each worn 3 months by patients. Twenty-four patients with KOA were assigned in a randomized crossover trial a valgus three-point bending system brace (V3P-brace), an unloader brace with valgus and external rotation functions (VER-brace) and a stabilizing brace used after ligament injuries (ACL-brace). Functional questionnaires and gait assessment were carried out before and after each brace wear …

Subject-Specific Regression Equations To Estimate Lower Spinal Loads During Symmetric And Asymmetric Static Lifting, F. Ghezelbash, A. Shirazi-Adl, Z. El Ouaaid, A. Plamondon, N. Arjmand

Études primaires

Workplace safety assessment, personalized treatment design and back pain prevention programs require accurate subject-specific estimation of spinal loads. Since no noninvasive method can directly estimate spinal loads, easy-to-use regression equations that are constructed based on the results of complex musculoskeletal models appear as viable alternatives. Thus, we aim to develop subject-specific regression equations of L4-L5 and L5-S1 shear and compression forces during various symmetric/asymmetric tasks using a nonlinear personalized finite element musculoskeletal trunk model. Kinematics and electromyography (EMG) activities of 19 young healthy subjects were collected during 64 different symmetric/asymmetric tasks. To investigate the reliability and accuracy of the musculoskeletal …

Theoretical Investigation Of The Low Frequency Fundamental Mechanism Of The Objective Occlusion Effect Induced By Bone-Conducted Stimulation, Kevin Carillo, Olivier Doutres, Franck Sgard

Études primaires

The objective occlusion effect induced by bone-conducted stimulation refers to the low frequency acoustic pressure increase that results from occluding the ear canal opening. This phenomenon is commonly interpreted as follows: the bone-conducted sound “leaks” through the earcanal opening and is “trapped” by the occlusion device. This instinctive interpretation misrepresents the fundamental mechanism of the occlusion effect related to the earcanal impedance increase and already highlighted by existing electro-acoustic models. However, these models simplify the earcanal wall vibration (i.e., the origin of the phenomenon) to a volume velocity source which, in the authors' opinion, (i) hinders an exhaustive comprehension of …

A Validated Uplc-Ms/Ms Method For The Determination Of Aliphatic And Aromatic Isocyanate Exposure In Human Urine, Maggy Lépine, Lekha Sleno, Jacques Lesage, Sébastien Gagné

Études primaires

4,4′-Methylenediphenyldiisocyanate (MDI), toluenediisocyanate (2,4-TDI and 2,6-TDI), and 1,6′-hexamethylenediisocyanate (HDI) are all commonly used in the production of polyurethane-containing materials in different application areas. Workers exposed occupationally to these compounds may develop sensitization with the potential to lead to asthma. Isocyanates are metabolized in vivo by conjugation to macromolecules and/or by acetylation prior to being eliminated in urine. The hydrolysis of urine samples releases free amine compounds from these metabolites as biomarkers of exposure, specific to each parent isocyanate: 4,4′-methylenedianiline (MDA), toluenediamine (2,4-TDA and 2,6-TDA), and hexamethylenediamine (HDA). To address the need for a validated method that could be used for …

Development Of A Method For Quantification Of Toluene Diisocyanate And Methylenediphenyl Diisocyanate Migration From Polyurethane Foam Sample Surface To Artificial Sweat By Hplc-Uv-Ms, Aleksandra Donchenko, Simon Aubin, Sébastien Gagné, Mark Spence, Livain Breau, Jacques Lesage

Études primaires

The US Environmental protection agency (EPA) has published guidance that includes test procedures for evaluating indoor exposure to chemicals from products. One of the test procedures represents the migration test for evaluating potential dermal exposure from home furniture. Such an evaluation involves the chemical measurement of the sweat which is currently unavailable in the literature. The objective of this project was to develop and validate an analytical method for quantification of migration of 4,4′-methylenediphenyl diisocyanate (MDI), 2,6-toluene diisocyanate (2,6-TDI) and 2,4-toluene diisocyanate (2,4-TDI) from a polyurethane (PU) flexible foam to artificial sweat that meets the recommendations of the EPA test …

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 …

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 …

On-Site Comparison Of The Osha 47, Asset Ez4-Nco, Iso-Chek, Dan, And Cip10 Methods For Measuring Methylene Diphenyl Diisocyanate (Mdi) At An Oriented-Strand Board (Osb) Factory, Simon Aubin, El Mekki Hamdi, Audrey Joly, Philippe Sarazin, Jacques Lesage, Livain Breau, Mark Spence, Sébastien Gagné

Études primaires

Diisocyanates are occupational contaminants and known sensitizers causing irritation (skin and respiratory tract) as well as occupational asthma. Because of their physicochemical properties (semi-volatile and high reactivity) and low occupational limits, diisocyanate exposure evaluation is still a challenge nowadays for industrial hygienists and laboratories. The objective of this study was to compare the methylene diphenyl diisocyanate (MDI) concentrations measured by five methods using different collection or derivatization approaches in an oriented-strand board (OSB) factory. The methods used were: OSHA 47 (filter, 1-(2-pyridyl)piperazine) (OSHA), Asset EZ4-NCO (denuder and filter, dibutylamine) (Asset), Iso-Chek (double-filter, 9-(N-methylaminomethyl) anthracene and 1,2-methoxyphenylpiperazine), DAN (filter, 1,8-diaminonaphthalene), and …

Performance Of Mechanical Filters Used In General Ventilation Against Nanoparticles, Clothilde Brochot, Pooya Abdolghader, Fariborz Haghighat, Ali Bahloul

Études primaires

With an equal mass, nanoparticles (NP) have a higher toxicity than particles with the same chemical composition but with larger surface area. However, the toxicological knowledge concerning NP is still insufficient to establish limit values of exposure. To seek the lowest exposure level, filtration is a simple and effective way to capture particles, including NP. According to ANSI/ASHRAE 52.2 standard, ventilation filters efficiency is tested for particles ranging from 0.3 to 10.0 μm. Performances of entire filters for NP are still very limited and particle size of 300 nm (0.3 μm) is commonly used as the most penetrating particle size …

Qualitative Knowledge Of Filtering Facepiece Respirators For Filtration Performance Tests During The Covid-19 Pandemic, Clothilde Brochot, Mohamed Nejib Saidi, Ali Bahloul

Études primaires

Background: During the COVID-19 pandemic, the pressure on health centers to obtain certified N95 filtering facepiece respirators (N95 FFRs) and the pressure on the FFRs production sector led to a diversification of FFRs’ supply chains, with the approval of several government authorities.

Objective: The main issue then becomes whether these purchased FFRs are as effective as the FFRs commonly used in the pre-COVID-19 period.

Methods: The most efficient way is to test these FFRs under normative conditions. The setup used here allows to measure the pressure drop Δp (mbar) and the filtration efficiency E (%) of FFRs with a constant …

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 …

A Transfer Matrix Model Of The Iec 60318-4 Ear Simulator: Application To The Simulation Of Earplug Insertion Loss, Yu Luan, Franck Sgard, Simon Benacchio, Hugues Nélisse, Olivier Doutres

Études primaires

The IEC 60318-4 ear simulator is used to measure the insertion loss (IL) of earplugs in the ear canal of an acoustical test fixture (ATF) and is designed to represent an average acoustic impedance (in a reference plane) of the human ear. The ear simulator is usually modeled using a lumped parameter model (LPM) which has frequency limitations and inadequately accounts for the thermo-viscous effects in the simulator. The simulator numerical models that can better deal with the thermo-viscous phenomena often lack essential geometric details. Most related studies also suffer from the lack of experimental validation of the models. Therefore, …

Procedure To Measure The Penetration Of One Mechanical Filter For Nanoparticles: Validation By Comparison, Pooya Abdolghader, Clothilde Brochot, Fariborz Haghighat, Ali Bahloul

Études primaires

Nanoparticles (NPs) are particles of less than or equal to 100 nm in diameter. Due to their size, they have a significant effect on health and safety of people. Capture of these NPs in general ventilation systems by filters remains one of the most widely used means of protection due to its relative simplicity of implementation and its effectiveness for capturing various size of particles. In North America, filters used in general ventilation systems are tested by the ANSI/ASHRAE Standard 52.2 and are graded according to their efficiency, which is a function of particle diameter. However, the current standard limits …

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 …

Filtration Of Nanoparticles Applied In General Ventilation, Clothilde Brochot, Pooya Abdolghader, Fariborz Haghighat, Ali Bahloul

Études primaires

Nanoparticles (NPs) are particles with a diameter less than or equal to 100 nm. Because of their size, they pose a major challenge to workers’ health and safety. General ventilation is one of the solutions in order to minimize both occupational and general exposure.

In North America, ventilation filters are tested according to ANSI/ASHRAE Standard 52.2 and rated according to their efficiency results as a function of particle diameter. The most penetrating particle size (MPPS) is commonly accepted as being 300 nm, but it no longer represents the worst-case scenario in terms of particle diameter and filter penetration.

The purpose …

Halogenated Flame Retardants And Organophosphate Esters In The Air Of Electronic Waste Recycling Facilities: Evidence Of High Concentrations And Multiple Exposures, Sabrina Gravel, Jérôme Lavoué, Bouchra Bakhiyi, Miriam L. Diamond, Liisa M. Jantunen, Jacques Lavoie, Brigitte Roberge, Marc-André Verner, Joseph Zayed, France Labrèche

Études primaires

Background

In response to a worldwide increase in production of electronic waste, the e-recycling industry is rapidly rowing. E-recycling workers are exposed to many potentially toxic contaminants, among which flame retardants (FRs), mainly suspected of being endocrine disruptors, are thought to be the most prevalent.

Objective

To conduct an exposure assessment of four chemical groups of FRs in Canadian e-recycling facilities, and to identify the main cofactors of exposure.

Methods

Personal air samples were collected over a workday for 85 workers in six e-recycling facilities, grouped into three facility sizes, and for 15 workers in control commercial waste facilities. Total …

Maintaining Lumbar Spine Stability: A Study Of The Specific And Combined Effects Of Abdominal Activation And Lumbosacral Orthosis On Lumbar Intrinsic Stiffness, Christian Larivière, Jean-Alexandre Boucher, Hakim Mecheri, Daniel Ludvig

Études primaires

Abstract

Background:

Two potential interventions for enhancing lumbar stability are to actively increase abdominal muscle activity, either through the abdominal drawing-in maneuver (ADIM) or bracing, and passively increase lumbar stiffness using a lumbosacral orthosis (LSO).

Objective:

To compare the increase in lumbar stiffness after 2 active interventions (ADIM versus bracing) and 1 passive intervention (LSO), and to evaluate the combined effect of active (abdominal bracing) and passive interventions.

Methods:

In this experimental and comparative study, lumbar stiffness, a surrogate measure of lumbar stability, was estimated in 25 healthy individuals during 7 trunk perturbation conditions: (1) control, (2) ADIM, (3) bracing …