Aerobic capacity varies significantly with different types of training. Endurance training, such as long-distance running or cycling, improves aerobic capacity by enhancing the heart's pump efficiency and increasing muscle oxidative capacity. In contrast, high-intensity interval training (HIIT) can also boost aerobic capacity but may engage different metabolic pathways, promoting improvements in both aerobic and anaerobic systems. Optimal training for enhancing aerobic capacity also includes a blend of various intensity levels and durations, often contributing to better performance outcomes across multiple sports.