Essential endurance for success in marathon running includes a blend of cardiovascular fitness and muscular endurance. Runners require a robust aerobic base to sustain energy levels over long distances, which helps in delaying the onset of fatigue. Additionally, mental endurance plays a crucial role; athletes must handle physical discomfort and maintain focus throughout the race. Training typically involves long runs, tempo sessions, and interval workouts that develop both the body and mind for the marathon's challenges.