Barre is an exercise system based on the earlier work of Lotte Berk who began her craft in 1959. Though it has evolved over time, the basics remain: a combination of low-to-no impact movements set to fun and upbeat music that emphasizes stretching and strengthening, often times simultaneously. While barre is certainly not a dance class, the roots of these exercises sprang from modern dance and ballet, and often incorporate the ballet barre in some, but not all, parts of class. The barre itself is the original class prop, and can be used for leverage, creating both resistance and support, especially during core exercises. Benefits of barre include increased muscle tone, balance, flexibility, core strength, and joy, because barre is, above and beyond, so much fun! Repetitive eccentric and isometric movements quickly fatigue muscles, but allow for a swift recovery, which allows students to do barre most days of the week.
There’s a misconception that all barre classes include non-stop tucking. However, all BFA-approved teacher trainings stress a neutral spine. Yes, there are times when a tilt (without any glute-clenching) is cued to encourage that neutral spine, and yes, we sometimes flow from anterior to posterior pelvic tilts, but we land back in neutral.
This is a good article from Yoga Journal about tucking. Give it a read