Vacuum level effects on knee contact force for unilateral transtibial amputees with elevated vacuum suspension.

The elevated vacuum suspension system (EVSS) has demonstrated unique health benefits for amputees, but the effect of vacuum pressure values on knee contact force (KCF) is still unclear. The objective of this study was to investigate the effect of vacuum levels on KCF for unilateral transtibial amputees (UTA) using the EVSS. Three-dimensional gait was modeled for 9 UTA with five vacuum levels (0-20inHg [67.

Vacuum level effects on gait characteristics for unilateral transtibial amputees with elevated vacuum suspension.

Background: The elevated vacuum suspension system has demonstrated unique health benefits for amputees, but the effect of vacuum pressure values on gait characteristics is still unclear. The purpose of this study was to investigate the effects of elevated vacuum levels on temporal parameters, kinematics and kinetics for unilateral transtibial amputees.

Methods: Three-dimensional gait analysis was conducted in 9 unilateral transtibial amputees walking at a controlled speed with five vacuum levels ranging from 0 to 20inHg, and also in 9 able-bodied subjects walking at self-preferred speed.

Evaluation of knee joint forces during kneeling work with different kneepads.

The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors.

Evaluation of a force plate system for measuring center of pressure in railroad ballast.

Traditional biomechanical analyses have focused primarily on the human gait across hard, flat surfaces and provide little information about human locomotion as a function of work environment or terrain. The purpose of this study was evaluation of a force plate system for measure of center of pressure (COP) in railroad ballast by comparing its accuracy across three surface conditions (hard surface, mainline ballast and walking ballast) with two configurations (level and 7° cross-slope). Custom walkways and an isolation fixture were developed to rigidly attach a force plate beneath ballast surfaces to collect the COP.

Effects of bed height on the biomechanics of hospital bed entry and egress.

Background: Although a significant proportion of patient falls in hospitals occur in the vicinity of the hospital bed, little is known about the contribution of bed height to fall risk.

Objective: To compare lower extremity joint torques and angles during hospital bed entry and egress at two bed heights.

Methods: Twelve adults (age > 55) were purposively selected and had variety of strength and mobility limitations.

The effect of toe marker placement error on joint kinematics and muscle forces using OpenSim gait simulation.

Marker placement can be a significant source of error in biomechanical studies of human movement. The toe marker placement error is amplified by footwear since the toe marker placement on the shoe only relies on an approximation of underlying anatomical landmarks. Three total knee replacement subjects were recruited and three self-speed gait trials per subject were collected.

The influence of deformation height on estimating the center of pressure during level and cross-slope walking on sand.

Force plates are frequently used to collect the ground reaction forces (GRF) and center of pressure (COP) during gait. The calculated COP is affected by the material type and thickness covering the top surface. If the surface is deformable, these effects can be significant.

The Safety of Hospital Beds: Ingress, Egress, and In-Bed Mobility.

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients' ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down.

The effect of ergonomic laparoscopic tool handle design on performance and efficiency.

Background: Many factors can affect a surgeon's performance in the operating room; these may include surgeon comfort, ergonomics of tool handle design, and fatigue. A laparoscopic tool handle designed with ergonomic considerations (pistol grip) was tested against a current market tool with a traditional pinch grip handle. The goal of this study is to quantify the impact ergonomic design considerations which have on surgeon performance.

Association between lifting and use of medication for low back pain: results from the Backworks Prospective Cohort Study.

Objective: To evaluate relationships between lifting and lowering of loads and risk of low back pain resulting in medication use (M-LBP).

Methods: At baseline, worker demographics, psychosocial factors, hobbies, LBP history, and lifting and lowering (quantified using the Revised NIOSH Lifting Equation) were assessed. A cohort of 258 incident-eligible workers was followed up for 4.

The NIOSH lifting equation and low-back pain, Part 2: Association with seeking care in the backworks prospective cohort study.

Objective: The aim of this study was to investigate the relationship between the revised NIOSH lifting equation (RNLE) and risk of seeking care for low-back pain (SC-LBP).

Background: The RNLE is commonly used to quantify low-back physical stressors from lifting/lowering of loads in workplaces. There is no prospective study on relationship between RNLE and SC-LBP.

The NIOSH lifting equation and low-back pain, Part 1: Association with low-back pain in the backworks prospective cohort study.

Objective: The aim of this study was to evaluate relationships between the revised NIOSH lifting equation (RNLE) and risk of low-back pain (LBP).

Background: The RNLE is commonly used to quantify job physical stressors to the low back from lifting and/or lowering of loads. There is no prospective study on the relationship between RNLE and LBP that includes accounting for relevant covariates.

An improved OpenSim gait model with multiple degrees of freedom knee joint and knee ligaments.

Musculoskeletal models are widely used to investigate joint kinematics and predict muscle force during gait. However, the knee is usually simplified as a one degree of freedom joint and knee ligaments are neglected. The aim of this study was to develop an OpenSim gait model with enhanced knee structures.

The effect of lifting speed on cumulative and peak biomechanical loading for symmetric lifting tasks.

Background: To determine the influence of lifting speed and type on peak and cumulative back compressive force (BCF) and shoulder moment (SM) loads during symmetric lifting. Another aim of the study was to compare static and dynamic lifting models.

Methods: Ten male participants performed a floor-to-shoulder, floor-to-waist, and waist-to-shoulder lift at three different speeds [slow (0.

Study protocol title: a prospective cohort study of low back pain.

Background: Few prospective cohort studies of workplace low back pain (LBP) with quantified job physical exposure have been performed. There are few prospective epidemiological studies for LBP occupational risk factors and reported data generally have few adjustments for many personal and psychosocial factors.

Methods/design: A multi-center prospective cohort study has been incepted to quantify risk factors for LBP and potentially develop improved methods for designing and analyzing jobs.

Prediction of peak back compressive forces as a function of lifting speed and compressive forces at lift origin and destination - a pilot study.

Objectives: To determine the feasibility of predicting static and dynamic peak back-compressive forces based on (1) static back compressive force values at the lift origin and destination and (2) lifting speed.

Methods: Ten male subjects performed symmetric mid-sagittal floor-to-shoulder, floor-to-waist, and waist-to-shoulder lifts at three different speeds (slow, medium, and fast), and with two different loads (light and heavy). Two-dimensional kinematics and kinetics were captured.

The WISTAH hand study: a prospective cohort study of distal upper extremity musculoskeletal disorders.

Background: Few prospective cohort studies of distal upper extremity musculoskeletal disorders have been performed. Past studies have provided somewhat conflicting evidence for occupational risk factors and have largely reported data without adjustments for many personal and psychosocial factors.

Methods/design: A multi-center prospective cohort study was incepted to quantify risk factors for distal upper extremity musculoskeletal disorders and potentially develop improved methods for analyzing jobs.

Typical whole body vibration exposure magnitudes encountered in the open pit mining industry.

According to recent research, a causal link has been established between occupational exposure to whole body vibration and an increased occurrence of low back pain. To aid in the further development of an in-house health and safety program for a large open pit mining facility interested in reducing back pain among its operators, whole body vibration magnitudes were characterized for a range of jobs. Specifically, thirty-five individual jobs from five different areas across the facility were evaluated for tri-axial acceleration levels during normal operating conditions.

A revised back compressive force estimation model for ergonomic evaluation of lifting tasks.

Occupational back pain and injury are common and costly issues. Biomechanical models are often used to quantify job risk by estimating back muscle forces. In general, the most accurate models are also the most complex, creating demand for models that are both straightforward and accurate.

Development of a carpal tunnel syndrome screening method using structured interviews and vibrotactile testing.

Carpal tunnel syndrome (CTS) is a debilitating and expensive health problem. An inexpensive screening method that would differentiate between people who do not have CTS and those that may have CTS would be useful. The screening methodology investigated here had two phases: a structured interview and provocative vibrotactile testing (VT).

Effects of prolonged wrist flexion on transmission of sensory information in carpal tunnel syndrome.

Unlabelled: Carpal tunnel syndrome presents a constellation of symptoms which include discomfort (eg, pain, paraesthesia) and diminished sense of touch. This exploratory study simultaneously measured changes in tactile threshold and discomfort ratings during prolonged wrist flexion in symptomatic patients from a rehabilitation clinic and from a control population. Prolonged (15 min) wrist flexion significantly increased tactile threshold and discomfort ratings above baseline levels in both symptomatic and control populations.

Job level risk assessment using task level ACGIH hand activity level TLV scores: a pilot study.

Existing upper extremity musculoskeletal disorder analytical tools are primarily intended for single or mono-task jobs. However, many jobs contain more than 1 task and some include job rotation. This case/control study investigates methods of modifying an existing tool, the American Conference of Governmental Industrial Hygienists (ACGIH) Hand Activity Level (HAL) Threshold Limit Value (TLV), to assess the upper extremity risk of multi-task jobs.

Job level risk assessment using task level strain index scores: a pilot study.

This paper explores 2 methods of modifying the Strain Index (SI) to assess the ergonomic risk of multi-task jobs. Twenty-eight automotive jobs (15 cases and 13 controls) were studied. The first method is based on the maximum task SI score, and the second method is modeled on the NIOSH Composite Lifting Index (CLI) algorithm, named cumulative assessment of risk to the distal upper extremity (CARD).

High-risk head and neck movements at high G and interventions to reduce associated neck injury.

Background: Neck injuries are a significant concern for aviators of high performance aircraft. A recent comprehensive technical report on cervical spinal injury associated with exposure to sustained acceleration, from NATO's Research and Technology Organization, recommended delineating the neck muscles used by aviators in this flying environment and developing improved neck muscle strengthening programs in an attempt to reduce such injuries.

Methods: A review of current literature was conducted in the fields of biomechanics, ergonomics, orthopedics, neurology, neurosurgery, rehabilitative medicine, and aerospace medicine.