Blood Lactate Dynamics Reveal Distance-Specific Anaerobic Demands in 400 m Sprint Training

This study aimed to determine how anaerobic energy systems are activated during 350 m and 500 m running tests to identify which distance may more effectively develop special endurance for the 400 m run. Eleven elite male 400 m sprinters (6 in the 350 m group and 5 in the 500 m group) participated in the study. Plasma lactate levels were measured at several time points: before starting, after warm-up, immediately before the test, and 1, 3, 12, 20, and 40 min post-exercise. Blood lactate concentration ([La−]) was determined using the enzymatic Sentinel test (Italy). A difference in blood lactate concentration between groups was observed, reaching statistical significance at the 3 min post-exercise time point, although no significant changes were observed at other time points. The 350 m trial was associated with higher peak lactate levels, suggesting a greater acute anaerobic demand, while the 500 m trial required a longer recovery period for lactate clearance and return to homeostasis.