Vocational Injury Management

Vocational Assessment/Rehabilitation

Isokinetics machines are routinely used in injury management world wide. They are accepted as reliable, reproducible and valid for the assessment and rehabilitation of injuries by the clinical and research communities. Each year literally thousands of peer reviewed pieces of research are produced on the uses of isokinetics machines in medicine.

In the last decade isokinetics machines have been increasingly used in vocational assessment and rehabilitation (the assessment and rehabilitation of injuries in the work place setting) mainly in the USA.

Isokinetics machines can actually perform many different types of tests. Strength, endurance and range can all be tested either statically (isometrically) or dynamically (isotonically or isokinetically). In the dynamic tests both concentric and eccentric contractions can be assessed (allowing both raising and lowering to be assessed). Proprioception (ability to judge position in space and how fast any motion is) can also be fully assessed. Added together isokinetics machines are in fact the only assessment tool to allow all aspects of musculoskeletal and neuromuscular performance to be full analysed.

In vocational assessment/rehabilitation the main type of test used is the concentric isokinetic test. This is the most common test as it replicates most activities we perform in everyday and work tasks. 

Isokinetic tests are unique in that the machine will match the maximal effort of the person being tested. It does not matter if the subject can generate allot of force or very little. The isokinetics machine will match the force and adapt 2000 times per second (this is faster than the body adapts). As the isokinetic test is dynamic (it requires movement) it offers the ability to see the performance through range and at different speeds (from slow to fast motions). If the subject has pain or limitation due to musculoskeletal or neuromuscular factors the machine will adapt with the subject reducing its output appropriately.

Subjects with genuine problems will produce consistently low results.

Whilst subjects with no problems will produce consistently good results.

Subjects trying to fake an injury will give inconsistent results (know as high co-efficience of variance a mathematically generated number seen in the results).

As the test is dynamic rather than static force curves are plotted along the motion scale. Maximal effort will produce similar curves with respect to amplitude and shape. Someone faking an injury, (a symptom magnifier) will produce inconsistent curve shapes and these are all shown in the produced reports.

In vocational assessment/rehabilitation the results of Isokinetic Evaluation are normally used to identify employees who will or will not be able to return to their full role and those who are injury magnifying (faking injury).

For those who can return to their full role it allows the development of return to full duties plans. This will often include a framework for modified (or alternative) duties and a relevant time frame.

For those unlikely to ever return to full duties it offers the basis of an offer of alternative employment.

For those unable to return to any work duties it offers a framework of current abilities and limitations.

Isokinetic Evaluation provides an important objective evaluation of current ability and / or impairment. The assessment offers a bridge between perceived ability/impairment and actual ability/impairment. It is deployed most commonly in the injury recovery phase. Isokinetic Evaluation provides a means for a shift from injury absence to a vocational feasibility assessment offering attainable goals with the view to return to full duties.

The Process:

The process of vocational assessment/rehabilitation usually involves an initial assessment covering the following key points:

Initial assessment.

A isokinetic functional capacity evaluation (FCE) normally comprises;


A comprehensive screening and specific testing process leading to diagnostic classification or, as appropriate, to a referral to another practitioner. Examination has three components: history, systems review, and tests/measures.


A dynamic process in which the physio/physical therapist makes clinical judgments based on data gathered during the examination.

Overall the evaluation normally focuses on key areas:


A present competence to perform an observable behavior or a behavior which results in an observable product.


An activity is the execution of a task or action by an individual.

Activity limitation.

Activity limitations are difficulties an individual may have in executing activities.


The highest probable level of functioning of an individual in a given domain at a point in time.


Impairments are problems in body function or structure such as a significant deviation or loss.

Job analysis.

The process of analyzing job duties and responsibilities to quantify functional job demands or performance expectations.

Job description.

A general statement of job duties and responsibilities.

Participation Restrictions.

Participation restrictions are problems an individual may experience during involvement in life situations.


What an individual does in his or her current environment. Performance is affected by a number of factors including behavioral attitudes, injury, pain and environmental and social stressors.

All reports offer high levels of validity (they contain what is technically known as content validity). This is demonstrated by the data showing that the content of a selection procedure is representative of important aspects of performance on the job. In work-injury management, FCEs are often used in case closure and may end in court decisions. Therefore, it is critical that FCEs are reliable and valid. For FCE tests to be reliable and valid, specific criteria must be met with regards to reliability, reproducibility and validity of the test. The factors involved in each of these areas are described in the Isokinetic FCE validity description:

If the employee is then sent for targeted rehabilitation Isokinetic evaluation can be used as follow up assessment/s once adaptation/s and or interventions have taken place.

Following Assessment

The assessment focuses on answering the referrer’s questions, and supplying them with the following information:

Can the employee perform their current role at this point.

Will the employee be able to return to their original role.

Are adaptations required to facilitate return to full duties.

What are the current physical abilities and limitations for alternative role. Is the employee likely to require re-deployment or alternative duties.

For employees who will return to full duties the following is addressed.

Designing a programme of exercises and or functional activities for the employee.

With an emphasis on strengthening and / or decreasing fatigue to help them get back into their full duties.

Modified duties (if required) are suggested in relation to the individuals capacity and the work place.

The return to full duties schedule of hours is defined, and advice is given on how to gradually increase the working hours over the appropriate length of time.

Provide regular monitoring of the employee during the process. Follow up assessments can be carried out to ensure progress and re-evaluate progress. This supports both the employee and employer through the process.

Rehabilitation recommendations/requirements.


Accelerates return to work whilst limiting (‘sick leave’) the amount of time the employee is absent form the work place.

Reduces costs to the employer in both work days lost and minimization of sickness absence management costs.

Early resolution of issues reduces the negative impact of long term absenteeism and pressure on other employees.

Sends a positive message about the employers active management of sickness absence.

Improves communication and co-ordination which results in reduced absence.

Guides then monitors and supports the return to full duties process.

Identifies, addresses and removes barriers to return to work.

Assesses the ability of the individual to return to their normal role. If this is not feasible recommends alterations to the role or alternative roles.

Early identification of individuals who will not be able to return to their employment.