Physical activity levels and quality of life relate to collagen turnover and inflammation changes after running.

The purpose of this study was to determine whether an association existed between self-reported symptom and function scores and tissue turnover or inflammatory biomarker changes after a running bout among individuals with and without an acute knee-injury history. A pre-test/post-test prospective cohort study design (Level II) of 22 participants was conducted. Eleven physically active individuals with a history of anterior cruciate ligament surgery and/or meniscus surgery within 4 years of study participation were matched to 11 healthy control participants. All participants completed self-reported outcome measures (Knee Osteoarthritis Outcomes Score and Tegner activity level) assessing knee symptoms and functional levels prior to the run. Blood samples were taken both pre- and post-30-minute run at a prescribed pace on a treadmill to determine serum biomarker concentration changes. Tegner activity levels were inversely related to type II collagen/type II collagen synthesis marker ratio biomarker changes after the run (r = -0.45, p = 0.01). Quality-of-life scores pre-exercise were inversely related to interleukin-1β changes after the run (r = -0.50, p = 0.02). No other correlation coefficients were statistically significant (r = -0.39 to 0.36). Ultimately, individuals with lower activity and quality-of-life scores experienced greater increases in collagen turnover and inflammation after a running bout, respectively. A gradual increase in activity (e.g., frequency, duration, intensity) may be warranted in this group prior to returning to activities that involve running. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:612-617, 2017.