Compare Anton and Vincent, the two brothers. How was Vincent able to beat Anton at swimming despite Vincent's weak heart?

The swimming competition has everything to do with self-esteem.... how Victor sees himself. Thus far, Victor has been presented as small, weak and fragile is contrasted, and in the shot after he has beaten Anton, we see a different Vincent.... a strong and powerful, who has a newfound self-confidence. Vincent no longer sees himself as useless, and he now understands that he can achieve his dreams of becoming an astronaut.