Watch the Quarter Notes online guitar lesson by Brad Carlton from Guitar Lab: Shuffle Secrets
This lesson explains the concept of quarter note triplets. In quarter note triplets, each quarter note receives two thirds of the beat. This can be perceived as two beats of eighth note triplets in which each pair of eighth notes are tied together. You would count them as follows:1 (trip) let (2) trip (let) 3 (trip) let (4) trip (let).
You will receive a drum groove track which will establish this rhythmic concept. Spend time counting and playing along with the track so you are rock solid in your understanding of this rhythm.