Book 28, Question 84
Why do some kids get tired faster than others?
Many things affect stamina: how much you've practiced, how well you've slept, what you ate, how fast you're running, and your age and growth.
Someone who gets winded doesn't mean they're weak, just not trained yet. Everyone's stamina improves with regular, enjoyable activity and patience. Comparing yourself to your past self is more useful than comparing with others.