Step 3: Collect Health and Medical Evidence

Begin your review from the date of your last equipment or process change. Gather information on the extent of WMSDs from OSHA logs of work-related injuries and illnesses, company medical records, workers’ compensation claims, insurance claims, absentee records, and job transfer applications.

You can calculate incidence rates based on the number of new cases reported and the total hours worked in a calendar year. Incidence rates for partial years can be calculated using hours worked through the time period in question. Incident rates are typically computed for the Total Recordable Cases incidents (TRC rate includes both cases with and without lost workdays) and for those cases with only Days Away, Restricted days or Transferred to another job (DART). When the total hours worked by all workers is not available, an estimate of 2,000 hours per year for each full time worker can be used. Compare incidence rates to those of other departments, other industries, other occupations, or the nation using The U.S. Bureau of Labor Statisticsexternal icon.

The incidence rate equation is calculated by the number of new cases per 100 worker years (which is equivalent to 200,000 work hours.

A prevalence rate is calculated when considering all active cases in a given time period regardless of when the case originated.

Use interviews and symptom surveys to identify the onset and nature of possible WMSDs that might otherwise go unnoticed. Surveys ask for the usual background information (age, sex, occupational history, present job tile, etc.) along with the nature, onset, location, timing, duration, and severity of MSD symptoms. Surveys also inquire about symptoms at previous jobs, the difficulty of job tasks, and medical history. You may include a body map so that workers can illustrate their discomfort. Administer surveys that are anonymous, voluntary, and to be completed on work time only. Rank-order the frequency and severity of complaints for each body part, then average this data for each department and/or job. Out of respect for workers’ personal information, use surveys only if the company is prepared to act on the results.

Gather evidence of WMSDs from periodic medical exams designed and administered by a health care provider. Workers give their medical history and complete a physical exam. Health care providers may also ask workers to complete range of motion tests, tenderness tests, etc. and report if they feel any pain. Physicians conducting medical exams should have no prior knowledge of workers’ existing diseases or job titles. WMSDs are present when MSDs in a certain part of the body are associated with a particular job function. Incidence rates and prevalence rates of MSDs are confirmed and specified by interviews, symptom surveys, and medical exams. For example, cashiers have more WMSDs in their hands and wrists than other supermarket workers, and those who perform more/longer checkout tasks have the most MSD problems.

Brannick, Levine, & Morgeson (2007) define job analysis as the study of a job and all of its components. The tasks of any job can be described in terms of tools, equipment, materials, workstation layout, physical environment, job demands, or organizational climate. A human resources professional or other experienced personnel conducts a job analysis to be able to describe everything that happens on the job. There is no standard protocol for conducting a job analysis to assess MSD hazards, so you may want to follow these objectives:

1. Obtain a complete description of the job, including the time needed to complete each task.
2. Ask employees if the way their job is done has changed over time.
3. Divide the job into tasks and actions.
4. Count and categorize the risk factors in each task and action. Consider work postures, workstation layouts, work surface heights, and reach distances. With work surfaces, consider slip resistance, hardness, and surface edges. Also consider the sizes, weights, and vibration of tools that workers use.
5. Determine the underlying cause for risk factors in each task and action. Don’t forget to consider whole body vibrations and other demands of the physical working environment. You can use biomechanics to measure muscle force and spinal disc pressure, physiological tests to measure oxygen consumption and heart rate, or psychological tests to measure perceived exertion.
6. Record the severity, frequency, and duration of each risk factor.

It may be difficult to determine what level or amount of exposure is harmful to your workers. NIOSH uses a variety of approaches to determine the appropriate job analysis for each workplace situation. You can use the NIOSH Lifting Equation to assess the risks associated with lifting and lowering tasks. You can compare the muscle strength required to perform a task to the strength of the individual workers performing this task. You can ask your workers to determine what they consider acceptable working conditions.

Current assessment tools can be found on the Washington State Department of Labor & Industriesexternal icon, Ohio Bureau of Workers’ Compensationexternal icon, Ergonomics – Thomas E. Bernardexternal icon, Cornell University Ergonomics Webexternal icon, AIHA Ergonomic Assessment toolkitpdf iconexternal icon and AIHA Flowchart to aide selection of an ergonomic assessment toolpdf iconexternal icon: