 Linemen in 3–4 schemes tend to be larger than their 4–3 counterparts to take up more space and guard more territory along the defensive front.As a consequence, many 3–4 defensive linemen begin their NFL careers as 4–3 defensive tackles, as younger players typically do not possess the size, weight, and strength to play on a 3–4 defensive front.They must be strong at the point of attack and are aligned in most cases head-up on an offensive tackle.