"Spill"

It does help the contain person b/c it forces a runner to come to him. However, with spill, the primary outside contain man is usually a LB or a secondary player. Teams that use spill as opposed to force usually have very fast LBs and overall good speed on defense. Slow teams don't want ball carriers to get to the sideline b/c there are less people out there. Teams with speed like to spill b/c they feel they can run someone down who has broken to the outside. If your team is slow in comparison to the teams you face overall, a force technique is best. The basic concept of force is a triangle shape. One guy forcing in, one guy forcing out, and one guy to fill the lane that is created. It can be done using an OLB forcing outside by attacking the inside shoulder of the lead back, pulling lineman, or whoever is coming at him, a C forcing inside by attacking the outside shoulder of the WR or lead back coming at him, and FS or SS filling in the lane that is created. This is a technique that needs drilling and discipline. Guys will want to go to the ball and forget thier assignment, if that happens the triangle is broken and it leaves another running lane. What force does is give a tackler a garauntee of where the ballcarrier is going to be. Now he just has to make the play. I recently heard Duke head coach Gerry Azzinaro speak on the topic of "force" for defending the run. He says he uses it b/c they don't have the talent of the other teams in thier league, so they give themselves garauntees by scheme. I hope some of this helps.