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

Abstract

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.

Can Muscle Soreness After Intensive Work-related Activities Be Predicted?

“…[21][22][23] Therefore, before this study, it was expected that a pain increase would occur. From the results of the present study, it can be concluded that DOMS generally occurs in healthy participants and is only minimally related to sex and age.…”

“…More detailed descriptive statistics on pain response after the FCE are presented in a different paper. 21 For pain intensity, 3 predictors remained in the final regression analyses (Table 2). Age, sex, and VO 2 max were predictive of outcome for pain intensity, explaining a total of 13% of variance.…”

Reliability and Safety of Functional Capacity Evaluation in Patients with Whiplash Associated Disorders

“…The second FCE was conducted 1 week later (median 7 days, IQR 6–7). This time period between the two tests needed be long enough to reduce carry-over effects and delayed muscle soreness [24], and short enough considering that the health condition of the study participants may still change. The second FCE was administered by the same tester.…”

“…Safety of the FCE was assessed by heart rate monitoring, observational criteria for effort level during work related tasks, pain reaction as measured with the Pain Response Questionnaire (PRQ) [24], additional pain medication, or reports of serious adverse effects. Participants were asked to score their pain for 17 separate body regions in an 11-point NRS, in which 0 was “no pain” and 10 was “worst pain”.…”

“…The participants were asked to fill in the PRQ on the subsequent days (using a diary) after the first WAD FCE until the day of the retest. The WAD FCE was considered safe under the following conditions: when the heart rate did not exceed the age-related maximum, when it did not exceed the maximum observational criteria for effort level during work-related tasks, when it did not lead to injuries, when it resulted in no serious adverse effects, when it did not increase by more than three NRS points [28], and when reported muscle soreness increased in the first 24–48 h (which is a normal response), subsided during the following 2 days and then returned to pretest levels within 5–7 days [24]. A response which did not adhere to this definition was interpreted as an abnormal response.…”