Apart from football, soccer might be the sport that is the most obsessed with team formations.

Talk about formations — “tactics” — is the most popular form of soccer analysis. English soccer magazine FourFourTwo is named for perhaps the most well-known formation — four defenders, four midfielders, two strikers. But different formations fade in and out of vogue, depending on which teams are winning and what’s popular.

The latest rage is the “back three” — playing with three dedicated defenders instead of four. It’s a good bet that, trends being what they are, your favorite team will soon be deploying this formation.

The genesis of the three-defender look comes, paradoxically, from the organization of the attack. Against a traditional back four, a combination of three forwards — usually one center forward, and two attacking playmakers behind him — is particularly well set up to exploit the gaps in the back line. Adding a forward to the traditional two, though, means that there is one fewer player in the midfield and defense.

Many teams are finding that playing three central defenders and four midfielders is a more effective method of organization. It results in a group of five tight defenders in the center of the field, with two wingbacks who have fewer defensive responsibilities than they would as fullbacks in a back four.

Just this year in the Premier League, the 3-4-3 (or, sometimes, 3-4-2-1) has swept the nation. New Chelsea manager Antonio Conte has always favored playing three defenders, and after his new team was thumped 3-0 by Arsenal early in the year, Conte decided to make the leap. Chelsea promptly won 13 consecutive league matches, a span in which it allowed a miserly four goals.

At Arsenal, where manager Arsene Wenger’s first act upon taking over in 1996 was to get in a fight with his team captain about whether the team should switch from a back three, the Gunners recently ended a two-decade run of playing with a back four. Wenger’s team promptly defeated Middlesbrough and Manchester City with three defenders.

Of course, the 3-4-2-1 is not a cure-all. This is especially true if the other team switches to a 3-4-2-1 of its own, which cancels out many the benefits of the formation.

This is exactly what many Premier League teams have tried against Chelsea this year, and yet the Blues have still swept through the league. The reason for this is the same reason that the best teams always win, no matter the formation — they are simply better at it. Two of the three center backs in Chelsea’s back three, David Luiz and Gary Cahill, and playmaker Eden Hazard were named to the Professional Footballer’s Association Team of the Year. Defensive midfielder N’Golo Kante was the PFA Player of the Year.

The formation is less important than how Chelsea executed it. Tactics aside, in soccer or in football, this is always the basic truth.

Short takes

•  Alex Morgan is on the verge of a historic season with Lyon after she and her French teammates defeated Carli Lloyd and Manchester City in the Champions League semifinals. Lyon will win the French league title for the 11th consecutive year and is the favorite to win a sixth consecutive Coupe de France as well. If Lyon can add a Champions League title to that haul, it would mark the team’s second consecutive treble — historic dominance for any team.

• This is the final weekend before the Liga MX playoffs are set, and this tournament has been astonishingly even. Seven teams go into the weekend in contention for the final two playoff spots. Each of the six teams that have already qualified for the playoffs has a mathematical shot at winning the top seed.

• Good news for Lionel Messi, who had been suspended four international games for swearing at an assistant referee. FIFA upheld his appeal, which means Argentina will have its star for key World Cup qualifiers this summer and fall. That’s important, as the Argentines are in real danger of failing to qualify for next summer’s World Cup.

WEEKEND WATCH GUIDE

Premier League: Sunderland at Hull City, 9 a.m. Saturday, NBCSN. Yes, this is a battle between Sunderland, the worst team in the Premier League, and Hull City, which is comfortably in the bottom five. Sunderland is already relegated, but Hull has a chance to stay up. A game like this, for Hull, is literally worth millions of dollars.

La Liga: Villareal at Barcelona, 11:30 a.m. Saturday, beIN. Barcelona is tied with Real Madrid at the top of La Liga, but Madrid has four games left while Barca has only three. All Barcelona can do is win and hope for a slip-up from its great rival. This is the most difficult of the Spanish giant’s remaining games. Win, and hope — it’s all Barca can do.

Bundesliga: Mainz at Hamburg, 8:30 a.m. Sunday, FS1. I wrote a couple of weeks ago about Hamburg’s struggle to stay in the top flight. Since then it has lost twice, to teams that were struggling to stay out of the relegation places. Nevertheless, a victory against Mainz will take Hamburg into a safe spot. Three games remain.

Premier League: Manchester United at Arsenal, 10 a.m. Sunday, NBCSN. What was once the marquee match on the Premier League calendar has, this year, become a battle between two sides outside the top four. United manager Jose Mourinho says he’ll rest players for a Europa League semifinal next week. But is he just playing mind games with Arsenal?