Endurance in a marathon race refers to the athlete's ability to sustain a high level of physical performance over a long distance. It involves mental strength, training, and nutrition to maintain energy levels and pace throughout the 26.2-mile course. Marathon runners often train for months, focusing on both aerobic capacity and muscular endurance, essential for completing the race successfully. This concept also emphasizes the importance of recovery and hydration during the race to prevent fatigue and cramping.