Sergio and Marco challenge one another to teach a class to a playlist they put together for each other 'blind' and come up with choreo on-the-fly. Who taught it better? Leave your comments under the video.

Sergio and Marco challenge one another to teach a class to a playlist they put together for each other 'blind' and come up with choreo on-the-fly. Who taught it better? Leave your comments under the video.

Grab a set of free weights and sculpt and define your shoulders, biceps, triceps in this upper-body focused workout. You'll move through a standing arm series and finish off with a plank sequence and cool-down stretch to release tension.