title: Suprathreshold heat pain response predicts activity-related pain, but not rest-related pain, in an exercise-induced injury model.
abstract: Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR), a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal.
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Rogelio A
authors.initials: RA
authors.lastname: Coronado
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Corey B
authors.initials: CB
authors.lastname: Simon
authors.affiliation: Department of Applied Medicine and Rehabilitation, Indiana State University, Terra Haute, Indiana, Unites States of America.
authors.forename: Carolina
authors.initials: C
authors.lastname: Valencia
authors.affiliation: Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Parr
authors.affiliation: Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Borsa
authors.affiliation: Department of Physical Therapy, University of Florida, Gainesville, Florida, United States of America; Center for Pain Research and Behavioral Health, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Steven Z
authors.initials: SZ
authors.lastname: George
mesh_terms: D000293:Adolescent; D000328:Adult; D015444:Exercise; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D017288:Pain Threshold; D012044:Regression Analysis; D012146:Rest; D020069:Shoulder Pain / Q000503:physiopathology*; D055815:Young Adult