The influence of pain, kinesiophobia, and psychological comorbidities on the accuracy of rating of perceived exertion in UK military spinal rehabilitation

Introduction: Chronic low back pain (CLBP) is a leading cause of disability in the UK Military. Pain and psychological comorbidities have been reported to influence rate of perceived exertion (RPE). Exercise rehabilitation can be monitored using RPE; however, the accuracy of RPE in inpatient CLBP rehabilitation is unknown. Methods: A prospective cohort correlation study of 40 UK Military CLBP inpatients was completed. Disability (ODI), kinesiophobia (TSK), anxiety, (GAD7) and depression (PHQ9) were subjectively reported at the beginning and end of the 3-weeks. Pain (VAS) and heart rate (HR) were recorded in the first aerobic exercise (AE) session (T1), and the final aerobic exercise session (T2). RPE was reported for each AE session. Results: At T1, a positive correlation was observed between RPE accuracy (-7.2  20.9), and pre-exercise pain (2.7mm  1.6mm) (p > .001) and ODI (31.0  16.9) (p > 0.05), and a negative relationship between RPE accuracy and average HR (135 bpm  22 bpm) (p > 0.001) was observed. At T2 there was no significant correlation between RPE accuracy (-4.4  22.6) and pre-exercise pain (2.8mm  1.6mm) or ODI (34.0  16.5) (p > .05). The strong negative relationship between RPE accuracy and average HR (137 bpm  20 bpm) remained at T2. Improved RPE accuracy over the 3-week rehabilitation programme was correlated to the change in average HR (r = -.314, p < .05). Conclusions: Comorbidities may negatively affect RPE accuracy in CLBP, but the magnitude of the influence reduces over intensive rehabilitation.