Originally Posted by Eagle Mum
... who the terms ‘contenders’ and ‘pretenders’ are referencing...
Not sure where/when the rhyming expression began, but it was a reference to students who have the drive and are willing to sacrifice to learn difficult concepts and material... and students whose primary interest may be boasting of taking a certain course of study (such as pre-med) in order to look good to others and are not deeply dedicated to learning the tough stuff.

The distinction expressed in that phrase ties in with the strategy some students use: previewing one or more texts in the subject matter before the class begins, in order to familiarize themselves with vocabulary, concepts, and material.