Seth Anderson forgot how much he loved the unfettered freedom of a smooth and empty parking lot.

That is until a global pandemic brought him back to in-line skating.

"When the lockdown happened, people — including myself — wanted something to get outside and do something different," Anderson said. "In-line skating gives you a different type of freedom than biking. You can go places you couldn't otherwise go and get in a great workout."

Cabin fever, shuttered gyms and nostalgia for the 1990s are leading to a resurgence of a sport that began in Minnesota 40 years ago.

Former skaters, or "bladers," as well as newcomers flocked to update gear. Stores and online inventories have been emptied of in-line skates, mirroring similar rushes for bicycles, camping equipment and even regular roller skates.

Rollerblade — the in-line skate brand founded by Scott Olson in 1980 in his parents' Bloomington basement — saw sales increase more than 300% from March to June, shipping more products domestically in May than any month in the past 20 years.

"Our sales were trending up slightly before COVID, but as soon as everyone got put on quarantine, it just exploded insanely," said Tom Hyser, a marketer at Rollerblade, now based in New Hampshire. Minnesota remains one of its strongest markets, he added. And sales at niche online companies spiked. Adam Bradley of Adam's Inline in Minneapolis, which sells high-end products to competitive in-line skaters, said he was inundated with calls and e-mails requesting skates for recreation or fitness.

"I specialize in really high-end parts, but these are people that just want to be outside and skate. They are tired of being locked up," he said. "A lot of them are people getting back into it after not doing it for years."

So Bradley called his vendor and was able to stock a single model of fitness skates. "My fitness skates are now outselling my [high-end] speed skates 10 to 1," he said, and sales are up 40% over this time last year.

Anderson grew up in the 1990s playing hockey in Duluth, where he spent summers practicing new tricks on his in-line skates with a close neighborhood friend. The X Games, ESPN's annual extreme sports competition, were just getting started and included in-line skating.

But like so many of the sport's first fans, Anderson gave up in-line skating after several years. His mom and coaches were concerned he'd get injured, he said. For other people, the lack of good trails or parks to skate pushed them away.

Olson has his own theory: People had too many other things they could do.

"That's the problem for a lot of things. All these little boutique fitness clubs popping up everywhere, and the TV and the phones are keeping more people in the house," said Olson, who still lives in Minnesota, splitting his time between a farm in Waconia and a houseboat moored off Nicollet Island in Minneapolis.

But many people left the sport when Rollerblading became passé — with underlying homophobia contributing to its precipitous decline.

"There was a media war between skateboarding and Rollerblading/in-line that resulted in ad hominem attacks on in-line: It was too gentle, it was too much an upstart, it was 'gay' in a pejorative sense," said Bob Rinehart, retired kinesiology professor and author of "Inline Skating in Contemporary Sport."

After growing at a compound annual growth rate of 29% year-over-year throughout the '90s, in-line skating peaked in 1998 at 27 million participants in the U.S., according to the National Sporting Goods Association.

In 2005, the X Games kicked out in-line skating, sending the sport to the fringes, said Shane McClay, a 37-year-old Minneapolis resident who's been skating since 1995. Last year, just 4.4 million Americans were in-line skaters.

"Our sport's been one of the most hated, underground sports for so long," McClay said. "Three years ago I was going to take a friend's 16-year-old to the skate park because he was getting really good, but he called me up at the last minute and canceled because his friends were teasing him about it."

The pandemic may start to reverse those perceptions. While the sport cuts across ages, older millennials, young adults and teenagers are driving its resurgence.

People in their mid- to late 30s grew up with in-line skates during the 1990s, a time when squads of kid bladers would recreate the "Flying V" formation from the 1992 hockey movie "The Mighty Ducks" on cul-de-sacs and parking lots.

Some of them are now parents and are seeking ways to get outside as a family. Others, passionate about fitness, see in-line skating as an alternative workout while use of their usual gyms or pools are restricted, Hyser said.

Teens and young adults, who weren't even born during the sport's zenith, are taking it up for the first time.

"Now we are seeing ages 15-24 coming into the mix, and that's awesome. It's super exciting for us because that is what our dream is — to get this new, younger demographic," Hyser said. "Right now, '90s nostalgia is cool. And it's a sport that doesn't have any rules. They can do it on their own terms."

McClay and some of his friends never stopped skating. As they got older, many shifted away from the adrenaline-based aggressive skating — or "aggro" — into endurance-based skating.

"As I've gotten into my 30s, people are more interested in getting out on the trails than getting hurt in the skate park," said 32-year-old Mike Lufholm.

He never gave up skating, even when it became less popular. But when the pandemic hit, Lufholm said, many of his old skating buddies started coming out of the woodwork.

"Everyone was calling me, asking me what skates to get and what the latest gear was," Lufholm said.

Overwhelmed with individual meetups, Lufholm created a Facebook page, Minneapolis Friday Night Skate, with information about group skating events. Every Friday, people meet up at B.F. Nelson Park in Minneapolis for a 10-mile skate, which includes a trip over the Hennepin Avenue Bridge that was shown in the 1994 sequel to "The Mighty Ducks."

It was Lufholm, who also grew up in Duluth, who inspired Anderson to get back out on his skates. Anderson, who is a personal trainer and fitness enthusiast, couldn't believe the advances in endurance skating and how much he enjoyed powering down a glassy bike trail or sprinting across a freshly paved parking lot.

"I can get a really great workout skating. The technology has gotten so much better. The materials are better, and there are so many different styles," Anderson said. "The sport of Rollerblading kind of died in the 2000s, but at the end of the day, if you are doing something to improve your health and fitness, no one is going to look down on you. If blading gives you the opportunity to improve your health, that's freaking awesome."

For its part, Rollerblade the company was ready for the moment with fresh social media content and how-to videos. Even if the sport loses some of the new adopters once the pandemic ends, executives say they expect sales to be much higher than they've been for the past decade.

For veteran in-line skaters, seeing newcomers join in the fun on the streets brings both a sense of redemption and possibility.

"We've always wanted to see our industry grow, but there hasn't been enough money in the industry to advance the products," Lufholm said. "So now that more people are buying skates, it's exciting to imagine what could come from this."

Kristen Leigh Painter • 612-673-4767