The correct answer to this open question is the following.
The four of the characteristics of public speaking (ie. message, channel, noise, audience, context, and delivery) that you should be most concerned with in preparing for this speech would be:
1.- Confidence. You must show your confidence to the audience to be trustful.
2.- Be authentic. You don't need to pretend to be someone else. You have to be authentic and use your own style. People want to listen to you and no other person.
3.- Passion. Your message has to be full of passion. You studied and played for that school. You know what it's like to wear your alma mater colors in the uniform, and you know what it takes to win. Well, show it in your speech.
4.- Engage with your audiences using anecdotes. Have two o three good anecdotes for your 5 to 10 minutes speech. Have one serious anecdote, one funny and one passionate. People love to listen to anecdotes and it is a great way to connect.