00:01This 3D printed foot is helping scientists solve one of the World Cup's biggest logistical challenges.
00:08Making the grass pitch feel the same at every stadium.
00:13We're simulating a 168-pound soccer player, which is the average weight of the last two men's World Cups.
00:20Here at the University of Tennessee, turf grass researcher John Sorokin has spent the last seven years
00:26preparing North America to host the world's biggest sporting event.
00:30A World Cup pitch is one that's going to be uniform, consistent, aesthetically pleasing,
00:35and hopefully not talked about at the end of the game.
00:38But that's easier said than done.
00:43The 2026 World Cup will be played across 16 cities in Mexico, the United States, and Canada
00:50with different climates, elevations, and stadium designs, all of which affect how grass grows and performs.
00:59Grass is a living organism. You abuse it, it will die.
01:02And once the tournament begins, there are no do-overs.
01:05The field has to withstand weeks of matches while remaining safe, consistent, and camera-ready
01:12for billions of viewers around the world.
01:16That's why FIFA has invested more than $5 million into John's grass-testing operation.
01:22So how is World Cup grass created?
01:25And what does it take to keep 16 pitches tournament-ready across three countries?
01:33It's a month before the 2026 World Cup kickoff,
01:37and John and his staff of more than a dozen researchers are still busy in their Tennessee lab.
01:44Since 2021, they've run more than 170 tests to solve a crucial problem.
01:49How do you make a field in Vancouver play the same as one in Miami?
01:54All World Cup fields have to have a natural grass surface,
01:58because FIFA wants every pitch to feel the same.
02:00So when a team plays in Miami, for instance, on Bermuda grass,
02:04and they go to their next game in Boston on Blue Rye,
02:06it's going to be the same field afoot.
02:08To make that possible, John invented the Flex device,
02:12a kind of crash test dummy for soccer fields that measures how firm, consistent, and safe a surface really is.
02:19All 16 stadiums will have one of these.
02:22As the robotic cleat slams into the turf,
02:26sensors measure how the surface responds.
02:30And we can go across an entire pitch and look at 77 locations and come up with like a heat
02:35map,
02:35and look at the variability of that surface.
02:37If one area is too soft, too hard, or too slippery,
02:42stadium crews can adjust the field before players ever step on it.
02:46Players are going to get hurt no matter what sometimes,
02:48but we want to lessen that likelihood that it's a result of the interaction with the surface.
02:53Keeping players safe is only part of the challenge.
02:56The ball has to roll and bounce the same way, too.
03:01Even small differences in the grass can change the speed of the ball or the angle of a bounce,
03:06something Argentina's players complained about after a 2024 game in Atlanta.
03:13So they use this machine to fire soccer balls at the turf at different speeds and angles,
03:19recreating everything from a simple pass to a shot on goal.
03:23It comes in at a 17 degree angle,
03:25and we don't want it to come up at more than a 14 degree angle as it goes in.
03:30So as we launch it, what we would normally have is high speed cameras, radar guns.
03:38The measurements help crews fine tune how each field is mowed, watered, and maintained,
03:43so the ball comes off the surface at a consistent speed and angle.
03:49But keeping the grass the same gets a lot harder when there's no sunlight.
03:55The hardest climates and conditions are going to be the indoor stadiums, right?
03:59We have to rely on 100% grow light situations because there's going to be no sunlight to help them
04:03grow.
04:03Without natural sunlight, the grass can weaken, recover more slowly, and be less resilient throughout the tournament.
04:10To tackle that problem, FIFA helped build this multi-million dollar research facility.
04:18So FIFA built a simulator dome that has grow lights to simulate those five stadiums.
04:23So we can grow grass inside with LED lights to simulate the sun.
04:29Each of these 12 bays mimics a different World Cup stadium.
04:32Some recreate fully enclosed venues like Atlanta's Mercedes-Benz Stadium,
04:37while others replicate partial sunlight conditions like at SoFi in Los Angeles.
04:42That helps researchers see how different grasses perform long before they're installed in a World Cup venue.
04:49They track things like ball bounce and root health, while soil probes monitor what's happening beneath the surface.
04:55And just like at a real World Cup field, they can simulate wear and tear.
05:00If you look down, it's got a roller, then we put soccer cleat studs on it.
05:04And when we go back and forth on the grass, we can simulate the cleat marks and the traffic.
05:09And this is how we simulate traffic on our individual plots.
05:12The goal isn't just to figure out which grass grows best.
05:16It's to learn how each field should be managed, such as lighting and treatment schedules,
05:22and how the pitch will recover between matches.
05:25After years of research, the team landed on a game plan.
05:29Kentucky bluegrass and ryegrass for cooler climates and indoor stadiums.
05:34And Bermuda grass for cities with warmer weather.
05:37Which should be mowed at a slightly lower height,
05:39and it grows different than the cool season grass.
05:42But they're very common grasses that you might have on a golf course,
05:45home lawn, or sports field anywhere.
05:46But we just intensify the management to make it fit for World Cup soccer.
05:51The actual game pitches are grown on 11 farms across North America.
05:56They're planted on top of plastic sheets to protect the grass' roots,
05:59so they can be transplanted into stadiums.
06:02What happens is the roots hit that plastic,
06:05and they don't penetrate the plastic, so they grow laterally.
06:07This is an example of a small piece of the sod growing on plastic.
06:12So this is the green grass on top, and you can see the abundance of roots on the bottom,
06:16because they couldn't go into below that plastic.
06:20So you haven't stressed the plant by cutting off its roots.
06:23Harvesting enough for one pitch takes about a day.
06:27You roll it up off of the plastic, and you can cut it like a pizza,
06:30and all those roots are intact.
06:33Refrigerated trucks arrive at farms in the middle of the night to avoid traffic.
06:37After being harvested in North Carolina, one pitch is hauled 12 hours north to New Jersey.
06:43It's headed to MetLife Stadium, home to the World Cup final,
06:46which will make it the most scrutinized field in the tournament.
06:52In 2022, one and a half billion people watched the Cup final,
06:57roughly 18% of the entire world population.
07:02Once the convoy of 27 trucks arrives, workers spend two days installing the pitch on top of a base layer
07:09of sand,
07:10using rakes and asphalt rollers to level and stabilize the surface.
07:15As it rains, that sand can drain really well.
07:19The following week, a Zamboni-like machine will inject millions of artificial fibers deep into the sand,
07:26so the natural grass roots can intertwine with them.
07:29They come into the machine and stitch in these fibers.
07:31They act like rebar to stabilize the sand.
07:3495% of the surface is going to be natural grass, and those fibers are below the canopy of the
07:39grass.
07:39So when a player runs and slides, they're not touching any of the fibers.
07:43There's a lot of layers that go into it.
07:45It's kind of like a parfait.
07:47Crews mow daily, monitor moisture, and re-roll the surface after every match.
07:53So if you watch a World Cup game, you'll see just before the game,
07:57they'll have the sprinkles on and water the whole field and get the grass wet.
08:01They'll turn the irrigation on again at halftime just before the players come out,
08:04get the grass wet again, and that helps the ball skip so it doesn't bounce too high,
08:08and it helps with the performance playability of the game, the speed of the game,
08:12and the quality of the game.
08:14And some of John's students will be there helping manage the fields in person.
08:18We've had a student that started working on this as a high school student.
08:22Now he's a freshman at the University of Tennessee,
08:24and this summer he's going to go work in Houston for one of the host cities.
08:27And that's the nice thing about this is the people that are all involved love what they're doing.
08:31It's not work for them.
08:32This is a passion.
08:33And we'll see you in the next one.
08:37This is what I used to remember.
08:38All right.
08:46Ladies, let's go to Widen.
08:47Usually we end up celebrating.
08:48That's too hard to do now.
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