I fell back,
Dazed, clutching my brow,
Groaning, “Oh my shin, oh my shin,”
And everybody peeled away from me
And dropped from laughter, and there we were,
All of us writhing on the ground for one reason
Or another.

Readers can tell that this is the climax of the poem, because it

gives information about what the speaker thinks and feels.
adds to the idea that the speaker feels like an outsider.
changes the speaker’s struggle to fit in with the other boys.
shows how the speaker’s problems with the boys are solved.