Effectiveness of and preference for a picture-based home office ergonomics assessment compared to a traditional in-person office ergonomics assessment: A case study from a Canadian University during the COVID-19 pandemic.

During the COVID-19 pandemic, telework best practices decreased in importance compared to the need for social distancing. It is important that ergonomics assessments for home office workstations are equally as effective as assessment for traditional offices to maintain teleworker wellbeing. The purpose of this case study is to compare a remote, picture-based, home office assessment to a traditional, in-person, office assessment for employees of one Canadian University.

The effect of training and workstation adjustability on teleworker discomfort during the COVID-19 pandemic.

Technological advancements have increased occupational flexibility for employees and employers alike. However, while effective telework requires planning, the COVID-19 pandemic required many employees to quickly shift to working from home without ensuring that the requirements for telework were in place. This study evaluated the transition to telework on university faculty and staff and investigated the effect of one's telework setup and ergonomics training on work-related discomfort in the at-home environment.

Evaluating movement performance: What you see isn't necessarily what you get.

With the goal of reducing injury and enhancing performance, movement screening tools score an individual's movements against a standard and because it is a predictor of injury symmetry is often included in the score. Movement quality screening tools only consider kinematic asymmetry, which may underestimate the degree of asymmetry present during movement. Consider joint forces: if these forces are atypical, additional stress is created and control is reduced, which can lead to injury if the asymmetry is not addressed.

Using an accelerometer and the step-up-and-over test to evaluate the knee function of patients with anterior cruciate ligament reconstruction.

Background: Evaluating the dynamic knee function of patients after anterior cruciate ligament reconstruction is a challenge. A variety of objective tests have been developed but for various reasons few are regularly used in the clinic. It may be practical to perform the step-up-and-over test with an accelerometer.

An Accelerometer as an Alternative to a Force Plate for the Step-Up-and-Over Test.

The step-up-and-over test has been used successfully to examine knee function after knee injury. Knee function is quantified using the following variables extracted from force plate data: the maximal force exerted during the lift, the maximal impact force at landing, and the total time to complete the step. For various reasons, including space and cost, it is unlikely that all clinicians will have access to a force plate.

The effect of sustained static kneeling on kinetic and kinematic knee joint gait parameters.

Despite epidemiological evidence for kneeling as an occupational risk factor for knee osteoarthritis, biomechanical evidence is lacking. Gait knee joint mechanics, a common measure used to study knee osteoarthritis initiation, were used in the present study to investigate the effect of sustained static kneeling on the knee. Ten healthy male subjects (24.

Subjective and objective analysis of three water pump systems carried by forest firefighters.

Background: The Mark 3 (M3) water power pump is an integral piece of wildfire fighting equipment. However, it is provided to fire stations without a carrying harness. The currently-used carrying harness is very uncomfortable, especially when carrying the pumps considerable distance in a forest to reach a water source.

Shouldering the load: A review of Joan Stevenson's work on occupational lifting and design evaluation of load carriage equipment.

Objective: In this paper, Dr. Joan Stevenson's work on assessment of the effects of lifting, supporting and transporting loads is reviewed. A defining attribute of this work is the use of objective, biomechanical measures as the basis from which a fuller understanding of all factors affecting worker performance can be obtained, and how such performance should be measured and evaluated.

Relationship between stair ambulation with and without a handrail and centre of pressure velocities during stair ascent and descent.

Introduction: Stair ambulation is one of the most challenging and hazardous types of locomotion for older adults and often requires the adoption of compensatory strategies such as increased handrail use to mitigate disability and increase stability. Centre of pressure velocity (VCOP) describes the neuromuscular response to shifts of the body's centre of mass and serves as an indicator of stability. Knowledge of VCOP may provide some understanding of strategies to improve measured and perceived stability during stair negotiation.

Local dynamic stability of the lifting kinematic chain.

While a stable trunk and centre of mass (CoM) trajectory are required during lifting, it is unclear how stability is controlled. Thirty healthy participants (15M, 15F) performed repetitive, symmetric lifting at 10 cycles per minute for 3 min with a load-in-hands equivalent to 10% of their maximum back strength. Short- and long-term maximum finite-time Lyapunov exponents (λ(max-s) and λ(max-l)), describing responses to small (local) perturbations, estimated the local dynamic stability of the foot, shank, thigh, pelvis, lower back, and upper back segments.

Case study: a novel biomechanical approach for evaluating extended body armor systems.

To combat the devastating effects of improvised explosive devices (IEDs), body armor that provides extended coverage has been developed. However, this extended coverage increases the armor's weight and may restrict movement. Throughout this case study, a novel technique to assess several armor systems was investigated.

Patients with osteoarthritic knees have shorter orientation and tangent indicatrices during gait.

Background: This study introduces two novel outcomes that could be used to identify people with knee osteoarthritis from healthy controls. These outcomes examine the lengths of paths on a sphere derived from knee angle and knee position during gait.

Methods: Participants with moderate knee osteoarthritis (n=47) and no knee pathology (n=51) walked overground.

Differentiation of young and older adult stair climbing gait using principal component analysis.

Introduction: Principal component analysis (PCA) has been used to reduce the volume of gait data and can also be used to identify the differences between populations. This approach has not been used on stair climbing gait data. Our objective was to use PCA to compare the gait patterns between young and older adults during stair climbing.

Reliability of lower limb alignment measures using an established landmark-based method with a customized computer software program.

The objective of the study was to evaluate the reliability of frontal plane lower limb alignment measures using a landmark-based method by (1) comparing inter- and intra-reader reliability between measurements of alignment obtained manually with those using a computer program, and (2) determining inter- and intra-reader reliability of computer-assisted alignment measures from full-limb radiographs. An established method for measuring alignment was used, involving selection of 10 femoral and tibial bone landmarks. (1) To compare manual and computer methods, we used digital images and matching paper copies of five alignment patterns simulating healthy and malaligned limbs drawn using AutoCAD.

The free moment in walking and its change with foot rotation angle.

Background: This investigation characterized the time-history pattern of the free moment (FM) during walking and, additionally, assessed whether walking with either an internally or externally rotated foot position altered the FM's time-history.

Methods: Force plate and foot kinematic data were acquired simultaneously for 11 healthy subjects (6 males, 5 females) while walking at their self-selected comfortable speed in 3 foot rotation conditions (normal, internal and external). The FM was calculated and normalized by the product of each participant's body weight and height prior to extraction of peak FM, occurrence of peak FM in stance and net relative impulse.

A comparison between a new model and current models for estimating trunk segment inertial parameters.

Modeling of the body segments to estimate segment inertial parameters is required in the kinetic analysis of human motion. A new geometric model for the trunk has been developed that uses various cross-sectional shapes to estimate segment volume and adopts a non-uniform density function that is gender-specific. The goal of this study was to test the accuracy of the new model for estimating the trunk's inertial parameters by comparing it to the more current models used in biomechanical research.

Mechanical factors relate to pain in knee osteoarthritis.

Background: Pain experienced by people with knee osteoarthritis is related to psychosocial factors and damage to articular tissues and/or the pain pathway itself. Mechanical factors have been speculated to trigger this pain experience; yet mechanics have not been identified as a source of pain in this population. The purpose of this study was to identify whether mechanics could explain variance in pain intensity in people with knee osteoarthritis.

Effect of foot rotation on knee kinetics and hamstring activation in older adults with and without signs of knee osteoarthritis.

Background: To determine the effects of changing the natural foot progression angle during gait (internal and external foot rotation) on the knee's adduction moment, lateral-medial shear force, and the ratio of medial-lateral hamstring muscle activation in those with signs of knee osteoarthritis and a matched healthy control group.

Methods: Twelve subjects with signs of knee osteoarthritis and 12 matched healthy control subjects were evaluated. A 3D gait analysis system calculated forces and moments at the knee while the subjects walked in three conditions: (1) normal foot position, (2) external foot rotation, (3) internal foot rotation.

Changes in the medial-lateral hamstring activation ratio with foot rotation during lower limb exercise.

This paper investigated whether the ratio of medial-lateral hamstring muscular activation could be altered with changes in foot rotation position (both internal and external rotation) during three standard lower limb exercises. It has been suggested that those with medial compartment knee OA activate the lateral hamstrings more than the medial to help unload the diseased compartment; therefore, preferential activation of this muscle during lower limb exercise may help to further decrease the stresses on the articular cartilage and be an effective intervention for knee OA and lateral hamstring injury. Thirteen healthy young adult subjects were tested and average medial and lateral hamstring EMG data during the full exercise, as well as the concentric and eccentric phases, were used to calculate the medial-lateral (M-L) hamstring activation ratio for each exercise and foot position.

Trunk density profile estimates from dual X-ray absorptiometry.

Accurate body segment parameters are necessary to estimate joint loads when using biomechanical models. Geometric methods can provide individualized data for these models but the accuracy of the geometric methods depends on accurate segment density estimates. The trunk, which is important in many biomechanical models, has the largest variability in density along its length.

Knee biomechanics of alternate stair ambulation patterns.

Purpose: This study compared the kinematics and kinetics of the knee joint during traditional step-over-step (SOS) and compensatory step-by-step lead-leg (SBSL) and trail-leg (SBST) stair ambulation patterns.

Methods: Seventeen (M:9) healthy adults completed five trials of ascent and descent using three different stepping patterns: 1) SBSL, 2) SBST, and 3) SOS. Kinematics and kinetics were collected with an optoelectronic motion-tracking system and a force plate embedded into a four-step staircase.

Self-efficacy mediates walking performance in older adults with knee osteoarthritis.

Background: Self-efficacy is a determinant of walking performance in older adults with knee osteoarthritis. We examined whether self-efficacy mediated the effect of age, psychosocial, impairment, and mechanical factors on walking performance.

Methods: Fifty-four participants with knee osteoarthritis completed the Six Minute Walk test and Arthritis Self-Efficacy Scale.

The effect of internal and external foot rotation on the adduction moment and lateral-medial shear force at the knee during gait.

It has been hypothesised that those with medial compartment knee osteoarthritis tend to externally rotate their foot during gait in order to unload the diseased compartment. This has been found to decrease the adduction moment at the knee during late stance, although the effects of foot rotation on shear forces at the knee have not yet been determined. Also, the effects of internal foot rotation on the knee during gait are not clear.

The influence of gait pattern on signs of knee osteoarthritis in older adults over a 5-11 year follow-up period: a case study analysis.

There is evidence that joint load is a factor in the development of osteoarthritis (OA) and, while altered gait profiles have been linked with OA, it is unknown if abnormal gait is a cause or effect of the disease. While the knee's adduction moment has been implicated in the development and progression of knee OA, it is also known that shearing forces are detrimental to the health of cartilage. The purpose of this pilot study was to examine the adduction moment and gait shear forces to determine if they may lead to signs of knee OA in older adults as they age.

Role of knee kinematics and kinetics on performance and disability in people with medial compartment knee osteoarthritis.

Background: Although gait characteristics have been well documented in people with knee osteoarthritis, little is known about the relationships between gait characteristics and performance or disability. Our purpose was to examine the role of knee kinematics and kinetics on walking performance and disability in people with knee osteoarthritis. We also examined whether pain mediated the relationship between the knee adduction moment and performance or disability.