Time-Course of Changes in Oxidative Stress, Anthropometric Measurements, and Physical Performance Responses Following Eight-Week Soccer Training

This study investigated oxidative stress, anthropometric measurements, and performance after an eight-week training program with soccer players. Sixteen U-17 male players participated in an eight-week training program, which included daily soccer training sessions lasting approximately two hours. Data collection was conducted at three distinct time points: one week prior to the start of the competitive season (Baseline), one week before the onset of the training program (Pre-training), and immediately following the eight-week intervention (Post-training). During the pre- and post-training phase, participants completed a standardized battery of physical performance tests, followed by blood sample collection. The battery of physical tests was performed in the following order: a) 30-m sprint, b) countermovement jump (CMJ), c) dribbling with/without the ball, and e) the field-based Yo-Yo Intermittent Recovery Test Level 2 (Yo-Yo IR2). Acceleration (10 m) and sprint time (30 m) were lower in the pre-training than in the post-training (<i>p</i> = .02 and <i>p</i> = .048, respectively). Creatine kinase levels were higher in the pre-training than at baseline and the post-training (<i>p</i> ≤ .001). Protein carbonyl levels were elevated in both the pre- and post-training compared to baseline (<i>p</i> ≤ .001). Catalase activity was higher in the post-training than at baseline (<i>p</i> = .001). The total distance covered in the Yo-Yo IR2 test and VO₂max increased in the post-training. This study demonstrated that an eight-week structured training program increases catalase activity and stabilizes creatine kinase and protein carbonyl levels following repeated exposure to soccer-specific physical testing.