 To be effective, 3–4 linebackers need their defensive line to routinely tie up a minimum of four (preferably all five) offensive linemen, freeing them to make tackles.The 3–4 linebackers must be very athletic and strong enough to shed blocks by fullbacks, tight ends, and offensive linemen to get to the running back.In most cases, 3–4 OLBs lead their teams in quarterback sacks.