Using Comparative or superlative adverbs which is correct grammar?

Question

Of all players, Kate moved the ball down the floor faster or fastest?

When comparing her with one other person (so that two people are being compared), use the -er word.

When comparing her with two or more other people (so that three or more people are being compared), use the -est word.

http://grammar.ccc.commnet.edu/grammar/adjectives.htm
Scroll down to Degrees of Adjectives.

http://www.lousywriter.com/adjectives_comparison.php

http://www.uottawa.ca/academic/arts/writcent/hypergrammar/compsupl.html

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What does it mean by Give an antonym for each optimistic?