Stamina is the ability to sustain physical or mental effort over a period of time. It is the capacity to endure fatigue and to keep going, even when faced with challenges or obstacles. Stamina is an important quality for many athletes, as it allows them to perform at a high level for extended periods of time. It is also important for people who engage in physical activities, such as hiking or running, as it allows them to have the energy and endurance to complete their goals. Stamina can be improved through regular exercise and training.