Endurance testing involves determining the amount of time a person can maintain an activity or perform a task or activity of daily living before becoming fatigued and needing to stop. The level of activity used to test endurance can be minimal to maximal.
Endurance testing is often used to assess a person's cardiovascular fitness to determine if cardiovascular disease is present and to evaluate the patient before embarking on a physical fitness program. The goal of exercise testing is to produce a sufficient level of exercise stress without too much strain on an individual. Exercise tests measure heart rate, blood pressure, respiratory rate, and breathlessness. The patient also reports on a rating of perceived exertion (RPE), which is a 15-point scale that
Maximal exercise testing can be used to determine the greatest amount of activity a person can endure and how rigorous the activity can be. Submaximal testing determines the best level for a person to safely engage in during a physical activity program.
Other types of endurance testing are important in determining how independent an individual can be in performing work activities. Such testing is particularly important in work hardening programs. A person who is injured on the job may be referred to a rehabilitation therapist for work hardening treatment. The therapist ascertains whether the individual can perform job tasks, and if not, designs a relevant rehabilitation program. It is often a challenge to accurately duplicate work environments.
A person with poor balance or coordination should not undergo endurance testing that involves movements that could cause dizziness or fainting. Persons with cardiac disease, hypertension, or diabetes could experience distress during endurance testing and must be closely monitored.
Clients are generally referred to a therapist by a physician treating them for a disease or disability. The physician often includes specific instructions. Endurance testing can be conducted in a variety of ways. A device such as a dynamometer is used to measure strength, and physical endurance can subsequently be charted. A therapist can determine endurance by instructing a client to perform a particular task for a specific length of time or perform the task for a specific number of repetitions. A therapist also can instruct a client to perform a task until becoming fatigued.
Exercise testing protocols
TREADMILL TEST. The treadmill is one of most commonly used endurance tests. Although the Bruce Treadmill Test protocol has been the most widely used, its results have been considered to sometimes overestimate a person's exercise capacity. Although it is best suited for younger and active patients, the Bruce protocol was designed to diagnose cardiovascular disease. During treadmill tests, individuals walk on various inclines at various speeds for increasing lengths of time.
BICYCLE ERGOMETRY. Bicycle tests are a common alternative to treadmill testing. A bicycle ergometer measures the individual's workload and increases workload in increments for eight to 12 minutes. For patients with lower limb limitations who cannot be tested on a treadmill or bicycle, the upper limb ergometer, a modified bicycle with hand-powered pedals, is used. For wheelchair-bound individuals, some clinicians have fabricated wheelchair ergometers. Such testing is not widely used because of lack of equipment.
TWELVE-MINUTE RUN TEST. This test consists of various run-walk tests. It is typically used to evaluate cardiopulmonary fitness for functional individuals. The patient is asked to cover the longest distance possible in 12 minutes, preferably by running, but by walking if needed.
TWENTY-METER SHUTTLE TEST. This test assesses maximal aerobic capacity and was designed for children, adults, and athletes. The subject runs between two lines spaced 20 meters apart. The examiner increases the pace at which the subject is required to run back and forth. The highest speed reached is the maximal aerobic speed.
ONE-MILE TRACK WALK TEST. This test was designed for many age groups and fitness levels. The examiner records the time an individual can walk one mile.
SELF-PACED WALKING TEST. This test was developed for the elderly and for those with low fitness levels. It involves walking at three speeds down a hallway while speed, time, stride frequency, and heart rate are measured. This protocol evaluates a person's walking efficiency and cardiopulmonary capacity. It does not actually test endurance but can provide guidelines for activities of daily living.
Many people are affected by low endurance or loss of stamina for a variety of reasons. After age 50, muscle strength and endurance begin to decline. People with physical disabilities also typically have endurance problems.
A typical treatment plan to build endurance includes such aerobic exercise as walking, jogging, swimming, and bicycling. Aerobic exercise improves cardiovascular health, which also increases endurance. Specific activity goals should be set for the client.
In work-hardening programs, therapists use several assessment devices to determine a person's capacity to return to work. The Baltimore Therapeutic Equipment (BTE) work simulator allows users to replicate most upper-limb motions and tasks involved in many job activities. For example, a client may be asked to repetitively lift a box weighing 40 pounds (18 kg) at any pace until becoming tired.
How well the simulator measures endurance has only been analyzed recently. Clients were found to have
an easier time completing tasks in the simulated environment than in the workplace. One occupational therapist who performs work-hardening programs for workers injured on off-shore oil rigs found that employees were able to perform the strenuous work in the air-conditioned clinical setting but did not last long after getting back to the humid conditions of the workplace. To improve the program, the therapist built a facility and duplicated the humid conditions, then tested clients for a full work day.
A thorough medical history is taken and all surgeries documented prior to administering an exercise test. Practitioners should inquire about current medications and any physical or cognitive limitations the individual may have. This alerts medical professionals to any underlying problems or possible complications. Other issues that should be considered when determining exercise testing protocol are the person's age, weight, nutritional status, mobility, assistive device use, and work environment.
To conduct an aerobic test, clinicians should ensure that the risk of injury is minimized. The client should be instructed how to properly perform exercises to avoid injury. Practitioners should keep in mind that an exercise test can be too stressful depending on the person's condition. Any medical professional involved in administering exercise testing should be certified in cardiopulmonary resuscitation (CPR).
Proper monitoring depends on individual circumstances. Heart rate is typically measured before, during, and after any testing procedure. The 12-lead electrocardiogram (EKG) is monitored before the test and periodically throughout the test. Following the test, the EKG and blood pressure are measured again, and every one to two minutes subsequently until levels return to baseline.
Following completion of a treatment program for building strength and endurance, a client should be educated on a continuing treatment program to be done at home. Strength and endurance will wane if activity is not maintained.
Occupational and physical therapists in return-to-work programs must take into consideration that work simulation techniques don't entirely duplicate working conditions.
The type of activity performed may also affect endurance. A person may show less endurance when performing an activity that he or she finds unpleasant or perceives as useless. The most effective intervention and treatment programs are associated with clients performing tasks they enjoy or that reflect the individual's self-worth.
Health care team roles
Collaboration among all caregivers plays a big part in any kind of rehabilitation intervention. Referring physicians should communicate with the therapist about the client and what treatment is recommended. Social workers or mental health professionals involved with the client should also be apprised of interventions, because emotional problems could affect test outcomes.
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The American Occupational Therapy Association. 4720 Montgomery Lane, Bethesda, MD 20824-1220. (301) 652-2682. <http://www.aota.org>.
The American Physical Therapy Association. 1111 North Fairfax Street, Alexandria, VA 22314-1488. (703) 684-2782. <http://www.apta.org>.
Meghan M. Gourley