21 Personnel Meaning in American Football

21 personnel in American football describes an offensive grouping with two running backs and one tight end. Usually, this includes one running back and one fullback. This term matters because it supports strong, physical running plays. The fullback leads blocks and clears space for the runner. Teams use 21 personnel in short-yardage and goal-line situations. Defenses often crowd the line, which opens passing opportunities. Play-action works well from this formation. For example, a fullback blocks a linebacker while the running back follows through the hole for a first down.