This stands for Dynamic Range of Motion and we perform this prior to every workout or activity!
Generally, we will perform a light jog, row or jump rope to get the blood pumping and to literally “warm up” the body prior to performing this routine. The entire procedure should take around 3 to 4 minutes at the most. Below is a full demo with explanation, including some common faults at the end. Check out the abridged version HERE, including the shoulder and hip movements.