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Pre-placement strength and endurance testing.

Many employers are concerned about the legal ramifications of screening employees. None wants to be charged with discrimination. Until recently, the principal concerns were sex and age discrimination in violation of the Civil Rights Act of 1964. However, the enactment of the Americans with Disabilities Act (ADA) has prompted further concern about discrimination against the disabled.

Many risk managers have become increasingly frustrated with the challenge of controlling musculoskeletal injuries and cumulative trauma disorders. In recent years, back pain alone has had more impact on business and demanded more management attention than any other safety and health topic. Cumulative trauma disorders are also on the list of management's biggest headaches.

Attempts to eliminate manual and repetitive tasks from the workplace have often been difficult. In some cases the nature of operations may preclude the elimination of heavy, exhaustive work through engineering revision. When the technology does exist, the cost of automated or mechanical handling equipment is sometimes prohibitive and may require considerable time for acquisition and installation. Something can be done in the interim, however, to minimize employee exposure to injury while workplaces are suitably engineered.

One interim measure is pre-placement screening. The objective of pre-placement screening is to identify prospective employees who may be predisposed to injury so that they can be placed in positions where the risk of injury is minimized. While medical histories, physical examinations and X-rays are part of traditional pre-placement screening, these methods have not been totally effective in identifying people with histories of, or predisposition to, musculoskeletal injuries. A high incidence of sprain and strain injuries continues despite years of traditional screening.

During the past 15 years, there have been major developments in the ability to accurately assess the physical demands of a task and safely measure the strength of individual workers. This has led to the use of strength testing as a pre-placement screening technique.

The National Institute of Occupational Safety and Health (NIOSH) has identified worker strength as a major risk factor in musculoskeletal injuries. Studies by D.B. Chaffin and others at the University of Michigan have shown that workers are three times more likely to be injured when performing jobs for which they have not demonstrated strength capabilities equal to or exceeding the job requirements. The fact that strength plays such an important role in musculoskeletal injuries is not surprising. What is important is that recent studies have identified the level of exertion at which injuries occur; the level of risk can be predicted more accurately now than in the past; and the technology now exists to allow safe, accurate and predictive testing. These advances have made pre-placement strength and endurance testing (PPSET) a more practical, economical and legal alternative than in the past.


Will a strength and endurance testing program help control employee injuries? In answering this question, management must consider a number of factors: ergonomic evaluations, medical facilities, legal interpretation, economic feasibility and practicality. As management sorts through the question, a few logical steps should guide the thought process. High stress tasks - those causing musculoskeletal injury - should be evaluated by a qualified ergonomist. The evaluation should identify the hazard causing injury (work site analysis), quantify the physical demands of the task (media and computer models), offer corrective measures to reduce the hazard (engineering controls) and calculate the residual task demands remaining after engineering changes have been made. Residual task demands may be sufficient to warrant additional controls, and PPSET may be an appropriate administrative measure to control the exposure.

As part of their decision making, management may confer with external resources (medical/therapy providers, technical consultants) to determine what testing equipment and expertise are available. While a variety of test equipment and methods exists, test procedures should simulate actual forces and body posture(s) of the employee while the task is performed or stress the identical muscle groups to the extent that they are stressed when the task is performed. The latter is referred to as a standard test battery.

If testing is implemented, management should periodically evaluate the need for the PPSET program, taking into account any workplace or equipment modifications that may substantially reduce the physical demands of certain tasks.


Some employee groups are understandably concerned about PPSET. Females, older workers and the physically disabled are groups that may be adversely affected by strength and endurance standards. The purpose of pre-placement strength/endurance testing is to determine whether a prospective worker has the physical qualifications (e.g., strength or endurance) to perform the required tasks. Consequently, generally healthy people with low strength and no disability are as subject to disqualification as people with disabilities (qualified individuals). A good case may be made that strength tests are not "medical" exams because the tests do not require a physician to conduct or interpret results, and the tests are not designed to screen out unhealthy or disabled workers but rather workers with low strength levels. There is no question that the ADA may cause employers currently engaged in preplacement screening to modify their programs. However, if the program is properly validated according to existing Equal Employment Opportunity Commission (EEOC) guidelines, the program may continue to be valid and effective. The following section describes the EEOC's validation criteria for testing and includes some practical guidelines.


There are several criteria that preplacement tests must meet to be considered legal and valid and to put a company in a position to avoid charges of discrimination. First, tests must be validated by the employer with the assistance of consultants (legal, medical and technical). However, management should understand that test procedures may still be challenged in the courts, even though the organization and its consultants agreed that the procedure has met accepted criteria. Accordingly, documentation of the validation process is very important.

Pre-placement tests should not present any undue risk of injury to those being tested and should be administered by trained technicians and professionals. Employers could face liability claims and lawsuits if employees are injured during the test. An unsafe test is one that exposes employees to higher stresses than they are capable of sustaining, one that does not permit them to remove the load passively or to regulate their exertion, or one that places employees in unstable postures while exerting a force. Test equipment itself should not expose employees to sharp edges, pinch points, fall hazards or other mechanical hazards. Conversely, safe tests are those where subjects can regulate stress levels and voluntarily release the device without bearing any additional load or exposing themselves to additional hazards.

Management may look to outside medical or technical consultants to administer the tests, or they may select other options. Testing options include: sending employees to an outside clinic that provides trained staff and proper equipment; retaining a provider with mobile equipment and trained staff to do testing at the employer's facility; purchasing the equipment and training internal staff; or retaining an external provider to administer tests using employer-owned equipment.

Another important criterion is reliability, which refers to the ability of a test to repeatedly produce consistent results. For instance, with no further intervention or changes, a person should be able to exhibit approximately (the coefficient of variation between tests should be less than 15 percent) the same strength level each time the test is taken. The information provided by the test battery must be convertible to a quantitative value, without which a valid standard cannot be established. There is no single value, standard or rate established for PPSETs. The nature of the test itself, the human characteristic being measured (strength, endurance, metabolic rate) and the job demands establish the standard.

Where strength and endurance tests are concerned, job-specific criteria imply the test reasonably simulates job strength and endurance requirements while using the same muscle groups and postures used on the job. Meeting job-specific criteria is important in establishing legal test validity.

It should be noted that a test procedure may be legally valid even if the test discriminates against a group or individual. Discrimination can be categorized as having disparate treatment or disparate impact. Disparate treatment can be defined as a condition where a group of people is treated less favorably. For example, if females were eliminated as candidates to perform certain jobs because their strength levels, as a group, are lower than males'. The specific group is singled out directly as being unqualified.

A definition of disparate impact is a condition where a group of people is "indirectly" screened out, although the screening practice appears neutral to all groups. For instance, one segment of the population may be more predisposed to a specific medical condition than others. If the test happens to screen out people possessing factors that lead to that condition, then the more predisposed group is singled out, indirectly.

An employer can justify disparate treatment and impact if lie or she can provide that the condition being screened (e.g., strength, endurance, color blindness, etc.) is job related or that there is some other business necessity (e.g., a company that does security consulting or guard service has a business necessity that its employees have reasonably clean criminal records). in the case of PPSET, employers will be required to demonstrate that the specific strength or endurance level is job related. This is part of the validation process; management should confer with legal counsel on this issue. If a company has a choice between several tests that will yield the same results, the test that results in the least disparate treatment or impact is the test that should be chosen.

Predictability, as a criterion, means that individuals not meeting the standard are at greater risk of injury than those who meet or exceed it. Various academic institutions and insurers have conducted studies supporting this. The studies chosen to demonstrate predictability at your company should be based on the job characteristics that are tested. Technical consultants should be able to identify the studies on which predictability of their test method is based.

The practical business issues associated with implementing a PPSET program may warrant more management attention than the legal issues addressed earlier. The practicality of pre-placement fitness testing depends on an employer's operations. For example, it may be practical from a business standpoint to test warehouse employees who are routinely involved in manual material handling. Their principal job involves moving, lifting, pulling and pushing - all tasks creating risk of musculoskeletal injury. On the other hand, it would be less practical to test light assembly workers whose exposure to heavy lifting is minimal. Strength testing should be considered for workers whose performance depends on strength and/or endurance of certain muscle groups.

In some cases an employer should answer the question, "If an applicant were to demonstrate marginal strength/endurance levels, would we still be inclined to offer employment based on skill level?" This situation may apply when hiring individuals with technical skills (e.g., maintenance personnel or machinists). While these employees may be exposed to strenuous tasks during the workday, their principal job involves utilizing the technical skills for which they were hired. Strength testing is not likely to be an appropriate control - other measures such as training or lifting aids will better control the exposure to injury.


A PPSET program may significantly increase screening costs. Compared to more common pre-placement medical tests, strength and endurance tests are more expensive. A battery of tests performed externally may exceed $100 per person, depending on the test and the market. Employers who choose to purchase equipment should perform a cost/benefit analysis that includes: initial capital expense, cost of job assessments, validation of testing protocol, program maintenance costs and potential savings from fewer injuries.

While some preliminary job assessments can be done internally, outside assistance will most likely be needed. Proposals from contractors should include costs for program assessment, validation and maintenance. It is not necessary to complete preliminary job assessments before making inquiries and requesting proposals from service providers. Consultants will often provide much of the information needed to determine the practicality and cost of the program before their "meter" starts to run.

Other elements of cost justification can be less tangible than the direct cost and predicted savings. For instance, the non-compensable lost time and medical care costs related to the injuries that will be prevented with a testing program in place should be estimated. Consider the extent of wages required to pay the injured employee's replacement. Increased productivity and efficiency of workers meeting or exceeding the physical standard, compared to workers not meeting the standard, can be quantified. There have also been studies indicating that proper job placement resulting from strength testing may help reduce other non-musculoskeletal injuries as well.

Management should consider time and staff issues associated with the program. Training and program administration time could be substantial, particularly in the early stages of implementation. Maintenance of a program generally involves retaining contractors (or internal staff) to provide service, record keeping, injury tracking and periodic program review.

Other time elements include the time to conduct the actual test. Existing employees bidding for jobs that require testing will be off the job for the amount of time it takes to undergo testing. How long will they be away from the job to undergo testing? Will it be off-site or on-site? Will they be paid? If testing is on-site, time involvement may be lower, but employees may expect to be paid. Offsite testing consumes more time but can be scheduled before or after business hours.


Some may consider that installing a PPSET program is impractical in plants with a unionized work force. While it is reasonable to expect that the union may view the program with suspicion, it is unreasonable to assume that they will reject the concept entirely. Union leadership should be advised of the company's plans early in the process to ensure that union concerns are addressed. The common ground for agreement should be the sustained safety and health of employees and the non-discriminatory feature of the program.

Seniority is a concern normally covered by a labor agreement (rather than by statute). Where more than one worker bids on a job, the more senior person may have bidding rights to the job and be the first choice. If a strength standard is in place, however, it is conceivable that a junior person may qualify over a more senior employee. To solve this dilemma, the labor agreement can provide that the "most senior person meeting the physical "qualifications" is entitled to the job.


There are a number of methods that have been validated and used to measure strength and endurance on the job. The following is not a recommendation of any one test, but a description of available methods. Dynamic tests involve measuring the physical limits of specific muscle groups while an employee performs a physical task through a range of motion. Although dynamic tests are difficult to standardize and validate because the range of motion required to perform a task presents too many variables, they more closely simulate actual work.

Isometric tests measure strength of specific muscle groups while the person sustains one posture. The measured strength represents that of the position and muscle group being measured. Consequently, the maximum strength of a person may not be measured because the position in which the subject can exert his or her maximum strength is not the position chosen for the test.

Isometric tests are easier to standardize because the static position reduces the number of variables involved and improves accuracy. The problem arises in validating that the test positions chosen represent the highest stress placed on the person during the actual work.

Test standardization is a typical problem in validating test procedures. It would be best for a company to use a standardized test procedure because this results in a more consistent test protocol, the time to administer the test is minimized, and the procedure can be repeated more effectively and accurately.

Iso-kinetric tests are a combination of static and dynamic tests where resistance is usually produced by the subject employee. The subject is under no further stress when he or she stops exerting force against the testing unit. This makes it a safer test than straight weight lifting (dynamic) tests. Also, the strength measurement is taken through a range of motion. This closely simulates an actual task and ensures that the subject's maximum strength is measured.

Iso-kinetic test equipment is generally more sophisticated than static strength equipment and costs considerably more, with equipment selling for $20,000 to $30,000. However, it may be the most valid testing method available.

Psycho-physical refers to testing procedures where the subject decides when his or her maximum strength has been achieved. The subject's perception of his or her limits is measured and the technician records the measurements. Psycho-physical tests can be dynamic or static.

Job simulation can be used to measure a prospective employee's physical ability to perform a task. The subject is asked to perform a series of tasks actually performed in the course of work. The risk of injury is greater than with other tests unless other job hazards can be designed out of the test. This may not be possible since job simulation may require subjects to exceed their limits in an attempt to complete the test.

The tests described above are primarily used to measure maximum strength while performing specific tasks. Metabolic expenditure is a form of endurance testing that measures physical ability (calorie expenditure) over a period of time while performing a series of physically demanding tasks. This would be best suited for placement in jobs that are continuously strenuous but do not necessarily require maximum strength.

Devices used in endurance testing, such as treadmills, exercycles, etc., are capable of measuring the subject's vital signs after a certain amount of work is performed. The subject has the ability to stop exercising and remove the stress at will.

Isometric strength testing is generally thought to be safer than dynamic testing. Additionally, studies have shown that isometric strength closely correlates to dynamic strength. Since isometric (static) tests are easier to standardize and more economical, they are more widely used. However, iso-kinetic equipment has become more popular and is now available through local medical and rehabilitation clinics. Companies therefore need not invest in the equipment, but can contract the services of the clinic that owns and operates the equipment. Some firms will take the equipment to the plant site in mobile units.

Pre-placement strength and endurance testing is only one part of an effective hazard control and injury management strategy. However, a properly designed program can help reduce employee injuries. Increased productivity, less turnover and lower. workers'compensation costs are common benefits as well.




In addition to its use as a preplacement screening technique, strength and endurance testing can benefit employers in other ways as well, such as rehabilitation, claims litigation, general fitness and improved job design.

Evaluation of the extent of injury and/or rehabilitation progress is a very common use of physical testing. Using such quantitative methods to evaluate an injured person's strength level provides a more objective means to determine ability to return to work and the level of physical activity a person can assume. It reduces the employer's dependence on the subjective views of the treating physician, which are often based partly on the injured worker's perception of his or her ability to return to work.

Strength and endurance testing also provides an accurate, objective measurement of the extent of disability, permanent or temporary, of a workers'compensation claimant. The extent to which these tests can be used will depend largely on the guidelines governing the assignment of disability in each state.

If maintained at a plant, test equipment can be easily converted to exercise devices to contribute to better overall fitness of the work force, improved morale and reduced medical claim costs. Finally, worker strength can now be objectively measured so that tasks and workstations can be designed based on the worker's physical capacity and ability. The guesswork can be taken out of job design because an employee's physical ability can be defined in advance. Facility engineers then ensure task demands are maintained below worker capacity.

W. Patrick Dolney is assistant vice president with M&M Protection Consultants in Cleveland, OH. This article is adapted from a technical paper published by M&M Protection Consultants.
COPYRIGHT 1993 Risk Management Society Publishing, Inc.
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Title Annotation:includes related article on additional uses of physical testing
Author:Dolney, W. Patrick
Publication:Risk Management
Date:May 1, 1993
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