What is the difference between the characters Squeaky and Gretchen in the story "Raymond's Run"?

Gretchen and Squeaky both are dedicated, particularly to running.  The compete well in the race, and have respect for each other becaue they are equal and fair competitors.   They also have a sense of self-assurance and pride - unlike the other girls, such as Mary Louise, they do not need to make fun of others to feel good.  They stand on their own and are good leaders.