In the 12 years since he became the youngest Argentine to score a World Cup goal, Lionel Messi has won more Ballon d’Or trophies, awarded to the world’s best player, than anyone before him. He has scored more official goals in a calendar year than anyone in living memory. He is the top scorer of all time in Spain’s La Liga, and this season, his performances have been characteristically devastating:

Lionel Messi’s performance in the 2017-18 La Liga season Statistic Per 90 min. League Rank* Goals 1.02 1 Assists 0.36 6 Expected goals 0.60 3 Expected assists 0.43 1 Successful dribbles 5.55 1 * Among attackers with minimum 850 minutes played Source: Football Whispers

And yet, in part because of the juvenile nature of soccer analysis, we have barely scratched the surface of understanding quite how Messi does it. This is most true when looking at his movement. Messi may get the ball more than most, but he, like all players, still spends the majority of his time without it — making runs, hiding in space, creating space for his teammates. It’s an integral part of his game that we know almost nothing about. The outcomes are there for all to see, but the process is obfuscated — we observe and quantify what Messi does on the ball, and are blind when he is off it.

Throughout his career, Messi has been criticized for walking. After an El Clasico match between Barcelona and Real Madrid in December 2017, there was widespread coverage of the fact that Messi walked 83 percent of the roughly 5 miles he covered that game. Despite this, he scored and assisted in Barca’s 3-0 trouncing.

This season in the Champions League (the only competition to release this basic running data), Messi ran comfortably less than any other elite attackers, averaging just less than 5 miles per 90 minutes. Naturally, a large portion of how much you run will be based on the team you play for and your role on that team. Teams that defend more will tend to cover larger distances, while certain tactical styles expect more of their forwards — Roberto Firmino of high-pressing Liverpool covered almost 7 miles per 90 minutes. But Cristiano Ronaldo of Real Madrid — which, like Barcelona, doesn’t press particularly stringently in its opponent’s half — averaged four-fifths of a mile more than Messi.

We’ve known this trait of Messi’s for quite some time: In 2014 World Cup coverage, Ken Early remarked that “only Messi has figured out how to win matches by moving less than everyone else.” Benjamin Morris wrote about the phenomenon for FiveThirtyEight after Argentina lost to Germany in the final. The most popular explanation has been that Messi walks to conserve his energy for critical moments, like a perfectly efficient machine. But even when he’s walking, new research suggests, he’s far from idle.

Luke Bornn, vice president of strategy and analytics for the Sacramento Kings, and Javier Fernandez, a data scientist at FC Barcelona, presented research at this year’s MIT Sloan Sports Analytics Conference in Boston that helps us shed some light on the phenomenon. Soccer is fundamentally a game of space and movement, so Bornn and Fernandez devised models using positional data that evaluate the occupation and generation of space by players.

“We can see at every instant the location of each player and the ball, and from this deduce how players’ movements create space for themselves and others,” Bornn said. “We can also see whether they do that actively, by running into open spaces, or passively, by staying in high-value locations while the play shifts away.”

The phrase “high-value locations” refers to another part of their research that quantified how much areas of the pitch are worth to either team. A rudimentary measure would simply be distance to goal, but after discussions with experts at Barcelona, Fernandez and Bornn realized that the value of space in soccer changes dynamically based on the positions of the players and the ball. Instead, they took the novel approach of extracting the value of space based on the behavior of the defending team. At the aggregate level, defenders will look to cut off the areas that are most dangerous relative to where the ball is.

Watch how Messi passively gains space on the right wing for Barcelona during an attack, with a dual view showing how Bornn and Fernandez dynamically value space behind the Villarreal defenders:

Applying the models to data from that La Liga match between Barcelona and Villarreal in January 2017, Bornn and Fernandez found that Barcelona’s most important principle space gainers were Sergio Busquets, Andres Iniesta and Messi.

They divide this space gain into two types: “active,” in which the player is moving at running speed, and “passive,” in which he is not. Iniesta and Busquets were passive just 43 percent and 52 percent of the time they held valuable positions. Remarkably, in about 66 percent of the moments Messi won control of valuable space, he was walking. Even while strolling, he is helping his team by holding ground in valuable areas, waiting for the ball to come to him.

They also looked at space generation and reception, when a moving player creates space for his teammates by dragging an opposing defender with him. In the same match, Messi was one of Barcelona’s top three players in terms of gaining space, along with Luis Suarez and Neymar. The three of them, in Barcelona’s devastating 4-3-3, would spread out wide across the pitch, forcing defenders to follow them. Bornn and Fernandez found that Messi and Suarez had a “special connection,” generating considerable amounts of space for each other.

Whether Messi consciously decides to go against the run of play with his movement is difficult to ascertain. “Can we say Messi gets a lot of his space by not chasing the play? Yes, that’s precisely what our research shows.” Bornn said. “Is he doing it deliberately? To answer that, you’d probably have to ask the man himself.”

As he battles to cement his reputation this summer, Messi will be under more scrutiny than ever before. We’re used to seeing him provide dazzling passes, incisive shots and glamorous dribbles, but we shouldn’t be afraid to keep our eyes on him even when the ball is elsewhere, and especially if he is moving slowly. For Messi never really walks; he prowls.

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