We’ve been through this about the Blue Jays — a promising team suddenly added both Troy Tulowitzki and David Price, and since then, the Jays have taken off. Since the day Tulowitzki first appeared in a Toronto lineup, the team has gone a league-best 21-4, storming into first place and showing few signs of slowing down. Right now, in the American League, the Blue Jays are probably the best ballclub. With two new elite-level players, there’s no team looking much stronger as we head for the playoffs.

Funny thing about that Tulowitzki-specific date — since then, the Blue Jays have gone 21-4, but the Cubs have gone a strikingly similar 21-5. Granted, the Pirates and Cardinals have also done well, but the Cubs have caught fire, featuring what’s been a top-five offense. Before this specific stretch, the Cubs were 10th in the National League in runs scored, and fifth in runs allowed. Over the highlighted weeks, they’re second in runs scored, and tied for second in runs allowed. Run prevention, they’ve mostly had. Run production is a newer thing. Top-to-bottom power is a newer thing. Just about everyone has been a positive contributor, but in particular, Dexter Fowler and Addison Russell have seemingly turned their seasons around.

Again, I mean, almost everyone’s hit. The whole team is in on this. But in August, Fowler has a 157 wRC+. Russell has a 113 wRC+, after what had been an extended slump. As is frequently the case, there’s a link between these changed offensive trends and talk of swing adjustments. Fowler has put in some work on his left-handed swing. Here’s what it looked like earlier on:

This only becomes interesting when you see the updated version:

The hands, maybe, have gotten a little bit lower. The bat, maybe, has changed where it’s pointing. But look at Fowler’s lifted leg. More recently, Fowler has shown a more aggressive leg kick, lifting the knee higher before striding forward. It doesn’t have that much to do with the swing itself, but it can alter a hitter’s timing, and it can possibly have positive effects on his balance. Okay, let’s move on. Russell is different, too. Russell, early in the season:

He’s staying back, but he has a wide foundation, and a conservative stride. Now for a recent image of Russell. This is more dramatic than the Fowler case:

Believe it or not, that’s the same hitter. He now seems a little more upright, but more significantly, there’s the whole front-leg thing. Instead of keeping his front leg in front of him and just lifting the foot slightly off the ground, now Russell brings his front knee close to his back one. This is a very aggressive leg kick, and if you remember what it looked like, it feels a little similar to Javier Baez. Some people would use the term “loading”. I don’t know enough about swings to know which are the appropriate terms to use, so I’ll settle for just posting the pictures. Look at the pictures! Different mechanics. It can’t be argued.

So Fowler is showing a higher leg kick. Russell, too, is showing a much higher leg kick. Already, that’s interesting — any on-the-fly changes are interesting. But, say, observe teammate Anthony Rizzo:

Well okay. That’s a big step. What if we looked at teammate Kyle Schwarber?

Holy god damn, it’s even more aggressive. Rizzo brought back his front leg. Schwarber did it more, such that his front foot actually crossed over his back foot. A picture like this doesn’t guarantee massive power, but it certainly suggests it. You look at a hitter doing this, and you don’t think he wants to hit the ball. You think he wants to obliterate the ball. (Which Schwarber has done.) Oh, but, I’m not finished. Starlin Castro hasn’t been real good this year, but he was good enough to pose for a photograph:

Looks like Russell. Or, Russell looks like Castro, I don’t know. They look the same, is the point. What about Miguel Montero?

That’s definitely a high step. It’s no Schwarber, and it’s a little shy of Rizzo, but you’re still looking at a transition state before a long stride. The right foot is well off the ground. Chris Coghlan?

This is the least-aggressive lift we’ve seen, with the foot not off the ground by much, but you still get some lower-body turn. The knees are brought more or less together before the stride. So, while Coghlan doesn’t look exactly like Rizzo, there are some of the same principles. Here, it’s just quieter.

Lest you think otherwise, not every single Cub does the same thing. Kris Bryant, somewhat famously, has a limited number of moving parts. His swing is simple, given the power he’s able to generate.

Bryant keeps a wide foundation and basically just has a toe-tap mechanism. Less famously, Jorge Soler keeps reasonably quiet:

Like Bryant, Soler stays wide and keeps his toe down. He also possesses enormous raw strength, so you figure he doesn’t have to do as much to tap into it. The general point here is that the Cubs have a couple of relatively quiet hitters, so it’s not like they have a complete team identity.

But, this is a team that’s had some pretty aggressive front legs, and I never embedded a screenshot of Javier Baez. Some were already in place, but more recently, Dexter Fowler has gotten more aggressive with his leg, and the exact same could be said of Addison Russell. They’ve made some similar tweaks, so while I don’t have any inside information on this one, it would appear this is a mechanism from which the Cubs hardly shy away. There are people who believe an aggressive front leg makes a hitter vulnerable to having his timing screwed with. Maybe or maybe not, but if the Cubs were concerned, they wouldn’t have instructed Fowler and Russell as they did. To this point, they’ve been better off. That could have to do with any number of things, but the swing is the first thing that comes to mind.