Biomarker Response After an Acute Running Bout in Participants with and without an Acute Knee Injury History

Abstract

The primary purposes of this study were to determine biomarker concentration levels at pre exercise and in response to an acute running bout in participants with an acute knee injury history (AKIH) in comparison to healthy control participants. The secondary purposes were to determine if self-perceived pre-exercise functional outcome score differences existed between participants with AKIH in comparison to healthy control participants, and whether these measures correlated with biomarker concentration changes after an acute running bout. Twenty-two (10 females, 12 males) college-aged individuals who were physically active participated in the study (11 with AKIH, 11 without AKIH). A two-group pre-test/post-test study design was utilized. The exercise bout consisted of running at 2.2 m * s -1 for 30 min on a motorized treadmill. Statistical significance was defined as p ≤ 0.05. The serum biomarker concentrations (i.e., COMP, IL-1ß, MMP-13, CTX-II, CPII, and CTX-II/CPII ratio) assessed in this study were not found to be significantly different based on AKIH status pre exercise and after 30 min of running. AKIH participants did have significantly lower pre-exercise functional scores compared to their matched healthy controls. Additionally, pre-exercise functional scores (i.e., KOOS quality of life and current Tegner activity) showed moderate negative correlations to IL-1ß and CTX-II/CPII ratio biomarker changes post exercise, respectively. The findings of this study indicate that an acute bout of moderate-intensity running is tolerated in a high-risk AKIH population and does not adversely affect knee biomarker metabolism. However, these findings should be interpreted with caution as it is yet to be determined if a higher exercise dose and/or intensity, as well as other varied types of exercise elicit adverse biomarker response within this population or if these findings are replicable in other populations (e.g., older aged). AKIH participants reported overall lower functional scores than healthy control participants, which may be indicative of impending structural or biomarker changes. Questions still remain about short- and long-term interventions post AKIH since there are many potential confounding factors that affect OA progression. Post-AKIH pathophysiology is complex and while there are unique variables that may accelerate OA onset, there may be an interaction effect of these variables that accelerate and propagate OA, and this still needs further investigation.