Pain Response of Healthy Workers Following a Functional Capacity Evaluation and Implications for Clinical Interpretation

Background and aim Functional Capacity Evaluations (FCEs) are used to quantify physical aspects of work capacity. Safety is a critical issue for clinical use of an FCE. Patients with Chronic Low Back Pain (CLBP) are known to report a temporary increase in pain following an FCE, but it is not known whether this increase is a normal pain response to FCE. It is currently unknown how healthy subjects respond to an FCE and whether this should be interpreted as a normal reaction after physical exercise. This study was performed to quantify the intensity, duration, location and nature of the pain response following an FCE in healthy subjects and to compare this pain response with the pain response of patients with CLBP from a previous study. Methods A total of 197 healthy working subjects between 20 and 60 years of age volunteered to participate in this study. All subjects performed a 12-item FCE. Pain response was measured by a self-constructed Pain Response Questionnaire (PRQ). Descriptive statistics were used to describe the pain response following an FCE. Mann–Whitney and t-tests were performed to compare the data from this study with data of patients with CLBP from a previous study. Results About 82% of all subjects reported a pain response following the FCE. The intensity of the pain response after 24 h post FCE was a median of 3.0 on a numeric rating scale (0–10). About 78% of all pain was reducible to muscle soreness. Pain was most often reported in the upper legs (51%), the lower back (38%) the shoulders (37%) and upper arms (36%). Symptoms decreased to pre-FCE levels in a mean of 3 days. The pain response of 2 subjects (1%) lasted for 3 weeks. The intensity and duration of the pain response of healthy subjects was not significantly different from the response of patients with CLBP. Conclusion Pain response of 99% of all subjects who reported a pain response was interpreted as normal. It was concluded that a pain response following an FCE can be expected in healthy subjects and that this pain response is a normal musculoskeletal reaction. The pain response of patients with CLBP resembles the pain response of healthy subjects.