The Relationship Between Muscle Damage and Acute Kidney Injury Biomarkers in American Football Players During Preseason Workouts

A lack of consensus exists in clinical diagnosis of exertional rhabdomyolysis (ER) following muscle-damaging exercise. Further, muscle damage has not been tested simultaneously with novel acute kidney injury (AKI) biomarkers in blood and urine. Since AKI increases the risk of chronic kidney disease and clinicians cannot rely on current clinical measures, it remains necessary to determine ideal clinical diagnostic measures reflective of AKI for athletes. Purpose/Specific Aims: The purpose of this study is to investigate associations among muscle damage and AKI biomarkers in American football players during preseason workouts. Methods/Study Design: We will recruit 30 American football players to voluntarily produce urine and blood samples for baseline and days 4, 7, and 10 of pre-season workouts. Researchers will record hydration measures, dietary intake, workout intensity/duration, WBGT during exercise, and serum creatine kinase (CK) and creatinine, serum and urinary neutrophil gelatinase associated lipocalin (NGAL), urinary kidney injury molecule-1 (KIM-1) and urinary cystatin C (CyC) for all time points of collection. Hypothesis: It is hypothesized that serum CK will demonstrate significant increases dependent upon workouts. We also hypothesize that novel biomarkers (NGAL, KIM-1, and Cystatin C) will indicate AKI despite asymptomatic serum CK increases. We hypothesize that novel biomarkers will rise and fall along with the creatinine and CyC, and want to determine the patterns to identify if the biomarkers will provide an earlier prediction for AKI. Significance of Study: This will be the first study to investigate AKI biomarkers as they relate to muscle damage in American football preseason workouts. Results from this study will help guide the clinical care of athletes following intense exercise in diagnosing AKI, ER, and muscle damage. Further, strength and conditioning programs that help athletes avoid AKI can be developed based on the outcomes of this research.