Effects of instructions on physical capacities outcome in a workers' compensation setting

Physical Capacity Evaluations (PCE) are often used in Pain Management Programs (PMP) to help determine patients' return-to-work status, continued rehabilitation and compensation.

Groups of patients participating in a 4-week PMP were given the PCE upon entry to the program and again near discharge. Change in performance between the first and second testing was examined.

The study was designed to examine the effects of instructions on patients' performance on the PCE.

An extensive literature suggests that, although commonly used, the PCE is of questionable validity in measuring actual physical capacity.

Patients were assigned to one of 2 physical therapists and given a PCE (in this setting, a dynamic vs static strength test) on admission and near the time of discharge. The assessment by the 2 therapists differed in the instructions they gave their patients for the PCE. Both therapists told their groups, "Do the best you can," but only one therapist added, "This test will be used to determine your job classification." In the second half of the study both therapists gave identical instructions, "Do the best you can," and did not add the explanation.

Patients who were informed that the test would be used to determine their job classifications performed considerably worse than those not so informed. When both therapists gave the same instructions, groups performed comparably, suggesting that therapist variables did not explain the differences between the groups.

Instructions on the PCE have an effect on performance.