Relationship Between Amino Acids and Performance Measures of Elite Soccer Players

Current theories suggest serum amino acids concentration can be used as an index of fatigue. The purpose was to quantify changes in the biomarkers, and performance measures over time and determine the ability of amino acids to detect changes in athletic performance. Twenty male collegiate soccer players (age, 20.5 ±1.2 y; height, 180 ±6cm; body mass, 78.2 ±6.3kg; body fat percentage, 12.1 ±2.4%; HRmax; 200 ±7 b∙min-1; VO2max, 51.5 ±5.1 mL∙kg∙min-1) were analyzed during this study. Amino acids were analyzed via an extensive panel of blood biomarkers, while performance measures via GPS, accelerometry, and heart rate. Athletes were monitored for 69 training sessions and 24 matches over a period of 4 months. The athletes were asked to provide a total of five blood draws consisting of 147 separate blood and urine biomarkers at various time points throughout the season. Three amino acids (Phenylalanine, Ethanolamine, and Beta-Amino Isobutyric Acid) entered the regression equation and were significantly related to sum playerload/min, F (3,73) = 12.847,