Getting bigger, stronger and more physical has been the theme of the Redskins’ offseason. General manager Scot McCloughan has emphasized being tougher, particularly in the trenches. On the offensive side of the ball, that means the end of the Mike Shanahan era of offensive linemen. Shanahan built a line full of smaller, more agile players to run the zone-blocking scheme. Jay Gruden wanted to bring more power and gap running plays to the Redskins, but didn’t necessarily have the personnel to do it last year.

This season, however, McCloughan has provided fifth overall pick Brandon Scherff and fourth-round pick Arie Kouandjio to beef up Gruden’s offensive line. Last year’s third-round pick Spencer Long is expected to compete for a starting spot at right guard too. Washington also brought in Bill Callahan as their new offensive line coach, replacing Chris Foerster, who was hired in 2010 to work under Shanahan.

All of these moves should help Gruden and the Redskins become more physical in the trenches. But there will be a transition period. Washington has spent the majority of the past five seasons running the outside zone, otherwise known as the stretch play in the zone-blocking scheme.

This is a perfect example of the base running play the Redskins have used recently. It comes from Washington’s 2013 season, Mike Shanahan’s last in the nation’s capital. It is the stretch play to the right.

Notice how all five offensive linemen take almost a drop step to the play side of the run. The zone scheme asks its linemen to be mobile enough to block to the sideline and reach the second level. Other traits in the zone scheme are noticeable here. Where it can, the offensive line works tandem blocks to help the smaller offensive linemen deal with the bigger defensive linemen. In this example, the left guard and center work one tandem block, while the right tackle and tight end work another.

In the zone scheme, the back-side blockers are taught to seal their blocks inside. As you can see here, both guards do a good job getting play side of their blocks and pinning the defenders inside. The left tackle and the center work to the second level to block the linebackers.

On the play side of the run, the blockers kick out the edge defenders. When both the play-side and back-side blocks are executed properly, it creates one big cutback lane for the running back, as you can see here.

In the zone scheme, the running back has specific reads he has to make, which determine precisely where he should aim to cut back to.

This is a zone run to the left. The running back’s first job in the zone scheme is to identify the end man on the line of scrimmage (EMOLS). On this occasion, the Giants defense has four down defensive linemen, which makes the defensive end the end man on the line of scrimmage. That is the running back’s first read.

The back always has a specific aiming point. Every stretch play will start with the running back aiming to the tight end. On this play, there wasn’t a tight end on the play side, but the back still runs to where the tight end would have started. The runner will read the EMOLS defender, and his position will tell the back if he should continue on his path to the edge or cut back inside. Here, the defender has positioned himself on the outside of his blocker, telling the back to cut inside and work to his second read.

If the first read tells the back to cut inside, then the back moves on to his second read. His second read is the first defender between the EMOLS and the center on the play side of the run. Here, that is the defensive tackle. The back again reads the defender’s position, which tells him to cut further back inside or go outside. Like before, the defender has outside leverage, which tells the back to cut further inside.

Those reads lead the back cleanly through to the second level of the defense.

The zone-blocking scheme has been very effective for the Redskins. The 2012 rushing attack that made Washington one of the best offenses in the league was built off the base of the zone scheme. But in recent years, the smaller linemen required to run it have been vulnerable to bigger, stronger defensive linemen that can drive blockers into the backfield.

Transitioning to the power scheme won’t be easy. It will require a lot of hard work to learn the principles of the scheme and how to execute it effectively. The offensive line and the running backs will have a new set of rules and way of doing things.

First, let’s look at the offensive line. This is a power run to the left. San Francisco is actually running this play with an unbalanced line, moving the right tackle to the play side between the left tackle and left guard, while the tight end shifts inside to fill the gap vacated by the right tackle. That gives the line extra strength on the play side of the run, which is something the Redskins might look to do with Scherff down the road.

In the power scheme, the play-side offensive linemen all have specific gaps to block. They are all told to down block, meaning to block the gap away from the play side of the run. Their first rule is to block a man in their back-side gap, or work to the second level if they have no defender in their gap. The right tackle, shifted to left tackle on this play, has a defender in his gap, so he will down block to the B gap and take on that defender. The left guard will help him initially pick up the block before working up to the second level. The center has perhaps the toughest job, but we’ll come back to that.

The play-side offensive linemen all down block, leaving the edge defender and the ‘point’ linebacker unblocked. The edge defender is left for the fullback or H-back to ‘kick-out,’ meaning to block him outside, sealing him on the edge and opening a hole for the running back. The back-side guard is told to pull from his position and work around as a lead blocker. His aiming point will be the ‘point’ defender, which here is the Sam, or strong-side, linebacker. The back-side tackle has a relatively simple job of walling off the back-side defender.

With the back-side guard pulling, the center has to cover two gaps. The center is already tasked with down blocking to the back-side A gap, but now he has to also cover the back-side B gap vacated by the pulling guard. In this case, the block is fairly simple as there is a defender in the A gap. But had the defense shifted that defensive tackle and put him in the B gap, the center would have had a tough assignment of reaching across to wall him off.

The ideal result of the basic power run is exactly what you see here. The play-side linemen all down block and move their defenders back off the line of scrimmage. They seal off a large portion of the defense on the back-side of the run. The fullback manages to kick out the edge defender and the pulling guard has the point defender in his sights.

Those are fairly significant changes from the offensive-line standpoint. But the role of the running back also changes in this scheme. Instead of following a strict set of rules and making one single cut in the zone scheme, the back has a bit more freedom in the power scheme. His initial instruction is to follow his lead blockers, the fullback and the pulling guard. But once he gets to the hole, he’s given more freedom.

You can see here, 49ers running back Frank Gore has multiple options, rather than one big cutback lane like we saw before. Running backs in the power system have to be a bit more instinctual. The zone scheme tells the back exactly where to go, whereas the power scheme asks the back to think on his feet and make quick decisions.

Getting skinny in the hole is a nice trait to have for a back in the power scheme. Running lanes aren’t often open for long in this scheme, so backs need to be able to burst through the hole and stay skinny while doing so, which means don’t give the defenders much of a target to tackle. You can see above just how small Gore makes himself as he bursts through the hole and avoids defenders.

Making multiple quick cuts on a single play isn’t uncommon in the power scheme. In the zone scheme, the Redskins running backs have been taught to make one cut and then get up the field. In the power scheme, the back needs to be more reactive. Here, Gore has already made one cut, but then a defender manages to win a block. Gore has to react quickly and make another cut in the hole to find the open space and elude the defender.

The power scheme will take some adjusting and getting used to for both the Redskins offensive linemen and running backs. It’s a big change from the zone-blocking scheme they’ve been accustomed to in recent years. But with bigger bodies provided by McCloughan and new coaching provided by Callahan, the Redskins should be better equipped for Jay Gruden to run the power scheme he wants this season.

Mark Bullock is The Insider’s Outsider, sharing his Redskins impressions without the benefit of access to the team. For more, click here.

More from The Post:

More NFL:  Home page | Sports Bog | Early Lead | Fancy Stats