This drill provides limited contact one step away from a perfect base. After your players establish the correct compact base, you can emphasize hip roll.
Any sled will do, but we prefer a stationary seven-man sled. Draw five 1-yard lines in front of and parallel to the sled. Seven players align one step (usually 1 yard) from contact, each shading a pad with his lead foot aligned in the middle of the pad.
On a "ready hit" command each of the seven linebackers steps with his lead foot and lightly touches the pad with his contact surface. The emphasis is always on foot placement first. Get the desired base and all else will fall into place. Practice a right-footed base and the next time up a left-footed one. Again, you can do many repetitions in a short time.
After a few times through without contact, have them explode with their hips off that base. Players should feel the power surge as the sled rocks upward off the ground (see figure 3.11).
http://www.humankinetics.com/AcuCustom/Sitename/DAM/125/E6103_482526_ebook_Main.jpg
Seven-man sled, one-step drill. Bs are setting their right-footed bases here.