Time to onset of pain: effects of magnitude and location for static pressures applied to the plantar foot.

Mechanisms that cause foot discomfort during prolonged standing are poorly understood. There is currently no method for evaluating discomfort associated with low levels of static pressure that are typical during standing. Pain thresholds were measured for 20 healthy participants by applying five levels of static pressure at different plantar foot locations.

Effects of anti-fatigue mats on perceived discomfort and weight-shifting during prolonged standing.

Objective: The aim of this experiment was to investigate the effects of anti-fatigue mats on perceived discomfort and behavioral responses (weight-shifting between the feet) during prolonged standing.

Background: Prolonged standing is a common requirement in the workplace and is a well-known cause of discomfort. Anti-fatigue mats have been shown to reduce discomfort resulting from standing, but no study has identified a particular mat that performs better than others or examined the relationship between discomfort and weight-shifting.

The effect of prolonged standing on touch sensitivity threshold of the foot: a pilot study.

Objective: To determine the effect of prolonged standing on touch sensitivity of the foot.

Design: An observational study with replications.

Setting: University laboratory.

Risk factors for lower extremity fatigue among assembly plant workers.

Background: Work-related fatigue of the lower extremities is a known cause of lost productivity and significant employer costs. Common workplace solutions to reduce fatigue levels include anti-fatigue matting, shoe orthoses, or sit/stand work stations. However, assessment of these anti-fatigue measures within the workplace has been limited.

Risk factors for foot and ankle disorders among assembly plant workers.

Background: Jobs that necessitate prolonged standing and walking activities are commonly associated with worker's complaints of foot and ankle pain. The objective of this study was to determine the relative contributions of work activity (time spent standing, walking, or sitting), floor surface characteristics, weight, BMI, age, foot biomechanics, and other demographic and medical history factors to the prevalence of foot and ankle disorders.

Methods: A cross-sectional observational study design was used to evaluate employees of an engine manufacturing plant.

Inter-worker variability in lower body postures during assembly line work: implications for exposure assessment.

This study evaluated inter-worker variability in lower body posture and work activity during highly-structured assembly line work. Data were collected from 79 unique assembly line workstations in an engine manufacturing plant. Because the plant utilized work teams, 4-8 workers rotated through each workstation.

Risk factors for plantar fasciitis among assembly plant workers.

Objective: The objective of this study was to determine the relative contributions of work activity (time spent standing, walking, or sitting), floor surface characteristics, weight, body mass index, age, foot biomechanics, and other demographic and medical history factors to the prevalence of plantar fasciitis.

Design: A cross-sectional observational study design was used.

Setting: The study site was an automobile engine assembly plant.

The effects of insertion method and force on hand clearance envelopes for rubber hose insertion tasks.

Objective: The aim of this study was to determine how hand space for manual insertion of flexible hoses is affected by insertion method and force.

Background: Adequate space is needed during assembly tasks in which workers join parts together with their hands. Hose installations are an example of such a task.

Analysis of the Third National Health and Nutrition Examination Survey (NHANES III) using expert ratings of job categories.

Background: Few epidemiologic studies have addressed the exposure-response relationships between work activities and symptomatic knee osteoarthritis (OA). This analysis used data from a national survey and ergonomists' ratings to address this issue.

Methods: Interview and knee X-ray data were obtained from the Third National Health and Nutrition Examination Survey.

Expert consensus ratings of job categories from the Third National Health and Nutrition Examination Survey (NHANES III).

Background: A method of occupational physical exposure assessment is needed to improve analyses using large data sets (e.g., national surveys) that provide only job title/category information as a proxy for exposure.

Using process control concepts to model conditions required for sudden-onset occupational injuries.

Sudden-onset injury results from a momentary energy exchange between an agent and host, producing immediately discernible tissue damage. These injuries are common in both occupational and nonoccupational settings; typical causes include falls, mechanical contact/crushing, exposure to temperature extremes, and exposure to electrical current. We review epidemiologic and engineering approaches to injury prevention and propose a process control model for describing risk-of-exposure to injury agents during the Pre-event phase of sudden-onset injury.

Effects of low back disability status on lower back discomfort during sustained and cyclical trunk flexion.

A laboratory study was conducted to determine the effects of back disability status on endurance time and perceived discomfort during trunk flexion. Eighty participants (40 with chronic or recurrent low back pain (CRLBP), 40 pain-free) were tested. The trunk was flexed to 15 degrees, 30 degrees, 45 degrees and 60 degrees under three conditions: 1) continuous static flexion; 2) cyclical flexion with 20% rest; and 3) cyclical flexion with 40% rest.

Case studies of ergonomic interventions in automotive parts distribution operations.

Ergonomic job analysis, intervention design, and intervention implementation are essential components of an ergonomics program designed to reduce worker exposure to risk factors associated with musculoskeletal disorders. As part of a 4-year study to reduce overexertion injuries in the service parts division of a major automaker, intervention case studies were identified that could be used at multiple facilities across the division. Interventions were developed and implemented.

Using multiple information sources to identify opportunities for ergonomic interventions in automotive parts distribution: a case study.

An essential activity in any ergonomics program is determining specific work locations and activities where physical demands place workers at increased risk of sustaining an overexertion injury. To do this, safety and health professionals rely on a variety of information sources to identify and prioritize opportunities for ergonomic interventions. As part of a 4-year project to reduce overexertion injuries in the service parts division of a major auto maker, a study was performed in 19 parts distribution centers to evaluate the contributions of the following information sources in identifying specific high-risk work locations and activities: (1) archival medical/injury records, (2) identification of "problem tasks" by plant-based ergonomic committees, (3) facility walk-throughs by experienced ergonomists, and (4) detailed ergonomic job analyses.

Developing ergonomic solutions for prevention of musculoskeletal disorder disability.

Numerous models have been proposed to help understand the relationship between personal and work factors that affect participation in work. The authors use a generic version of these models as a framework for identifying gaps between job demands and worker capacities. They describe metrics for assessing factors associated with causing or aggravating musculoskeletal disorders.

Shoulder disorders and postural stress in automobile assembly work.

Objectives: A case-referent study was conducted in an automobile assembly plant to evaluate the risk of shoulder disorders associated with nonneutral postures.

Methods: The cases were workers who reported shoulder pain to the plant clinic during a 10-month period and met symptom criteria (pain frequency or duration in the past year) in an interview; more than one-half also had positive findings in a physical examination. The referents were randomly selected workers who were free of shoulder disorders according to the clinic records, the interview, and the physical examination.

Workplace risk factors and occupational musculoskeletal disorders, Part 2: A review of biomechanical and psychophysical research on risk factors associated with upper extremity disorders.

Injuries and disorders caused by overexertion and repetitive motion are the leading causes of compensable lost-time cases in the United States. Epidemiological and laboratory-based research methods have been used to evaluate the significance of various risk factors associated with overuse injuries and disorders. The National Institute for Occupational Safety and Health performed a comprehensive review of over 600 epidemiological studies in 1997 and concluded that there was evidence of a causal relationship between workplace exposures to forceful exertions, repetition, awkward posture, and vibration and disorders of the neck, shoulder, and upper extremities.

Workplace risk factors and occupational musculoskeletal disorders, Part 1: A review of biomechanical and psychophysical research on risk factors associated with low-back pain.

Injuries and disorders caused by overexertion and repetitive motion are the leading causes of compensable lost-time cases in the United States. Epidemiological and laboratory-based research methods have been used to evaluate the significance of various risk factors associated with overuse injuries and disorders. The National Institute for Occupational Safety and Health performed a comprehensive review of over 600 epidemiological studies in 1997 and concluded that there was evidence of a causal relationship between low-back injuries and disorders and workplace exposures to forceful exertions, awkward posture, and vibration.

Work-related musculoskeletal disorders: comparison of data sources for surveillance.

Work-related upper extremity musculoskeletal disorders "associated with repeated trauma" account for more than 60% of all newly reported occupational illness, 332,000 in 1994 according to the U.S. Department of Labor.

The effect of size and fabric weight of protective coveralls on range of gross body motions.

This study evaluated the effects of garment size and fabric weight on range-of-motion (ROM). Ten male subjects performed a series of twelve gross body movements while wearing each of nine similarly styled coveralls. The coveralls were undersized, appropriately sized, and oversized, and were constructed from three different weights of poly/cotton fabric.

Median sensory distal amplitude and latency: comparisons between nonexposed managerial/professional employees and industrial workers.

To test for associations between occupation and median nerve dysfunction, measures of median motor and median and ulnar sensory amplitude and distal latency were compared among three populations: control subjects without occupational exposure to highly forceful or repetitive hand exertions (N = 105), industrial workers with hand/wrist symptoms (N = 103), and asymptomatic industrial workers (N = 137). Mean sensory amplitudes were significantly smaller (p < 0.05) and motor and sensory distal latencies were significantly longer (p < 0.

Perceived exertion and discomfort associated with driving screws at various work locations and at different work frequencies.

Eighteen subjects drove screws with air-powered tools into perforated sheet metal at three vertical and two horizontal work locations using three different work paces (8, 10, and 12 screws/min). Subjects drove screws with a pistol-shaped tool on the vertical orientation at knee, elbow, and shoulder height. They used an in-line tool to drive screws on the horizontal surface.

A checklist for evaluating ergonomic risk factors associated with upper extremity cumulative trauma disorders.

A two-page checklist for determining the presence of ergonomic risk factors associated with the development of upper extremity cumulative trauma disorders (e.g., repetitiveness, local mechanical contact stresses, forceful manual exertions, awkward postures, and hand tool usage) was developed and evaluated as part of a joint labour-management ergonomics intervention programme.

Back disorders and nonneutral trunk postures of automobile assembly workers.

A case-referent study was conducted in an automobile assembly plant to evaluate the health effect of trunk postures, such as bending and twisting, that deviate from anatomically neutral. Cases of back disorders were all those of workers who reported back pain to the medical department in a ten-month period and met the severity criteria of an interview. The referents were randomly selected workers free of back pain according to medical department records, an interview, and an examination.