This movement forces the back into a rounded position, but, the entire back is working here as opposed to when we see someone round the back due to weak muscles or not activating the back muscles during a lift.
I prefer the athlete to grab the keg slightly below the mid line to extend the range of motion slightly.
To begin, they will tilt the keg forward and bear hug the keg, once they have a secure grasp, they squat up explosively.
Reps can begin from the ground on each rep, or, go down until the keg almost touches the ground.