A STIMULUS-RESPONSE FRAMEWORK TO INVESTIGATE THE INFLUENCE OF CONTINUOUS VERSUS INTERVAL WALKING EXERCISE ON SELECT SERUM BIOMARKERS IN KNEE OSTEOARTHRITIS

Objective Compare changes in the concentration of serum biomarkers in response to continuous versus interval walking exercise in participants with knee osteoarthritis (OA). Design A two-phase sequential design. Twenty-seven participants with unilateral knee OA completed two separate treadmill walking sessions: 1) continuous 45-minute walking exercise and 2) three 15-minute bouts of walking exercise separated by 1-hour rest periods for a total of 45 minutes in an interval format. Participants reported their knee pain using the numeric pain rating scale and serum levels of biomarkers associated with tissue turnover [cartilage oligomeric matrix protein (COMP)], inflammation [Tumor necrosis factor-α (TNF-α)] and pain [neuropeptide-Y (NPY)] were evaluated at baseline and every 15 minutes for both conditions. Results Continuous walking resulted in a cumulative increase in COMP concentration up to 45 minutes, whereas interval walking was associated with return of COMP concentrations back to baseline at 45 minutes. There were no significant changes in TNF-α and NPY concentration during walking. There was a significant increase in pain compared to baseline in the continuous walking regimen only. Conclusion Incorporating rest breaks in walking regimens may impact the potential deleterious effects of longer continuous bouts on the knee joint as well as limit pain during exercise. The project described was supported by the University of Pittsburgh Medical Center Rehabilitation Institute, Pittsburgh Claude D. Pepper Older Americans Independence Center through (Grant number P30 AG024827), the National Institutes of Health (Grant numbers UL1 RR024153, UL1 TR000005 and K12 HD055931) and the Justus Lehman Award from the Foundation for Physical Medicine and Rehabilitation Corresponding Author: Prakash Jayabalan, MD, PhD, Attending Physician Scientist, Shirley Ryan AbilityLab and Assistant Professor, Northwestern University Feinberg School of Medicine, Chicago, IL, pjayabalan@sralab.org Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

https://ift.tt/2IO1g5o