“It’s very important what you put next to your skin,” says Efraim Nathan.

Professional team sports trainers across the U.S. trust Nathan to know. His Norristown-based company, Lontex Corp., makes Sweat It Out premium sweats and sports underwear, offering “Cool Compression” in its garments, which he believes “stretch differently” and speed injury recovery.

They’re not cheap: Sweat It Out garments can cost $70 and up, double what similarly marketed gear from global giant Nike fetches.

But Nathan is cheerful these days: He’s waiting for a federal judge to determine how much Nike may have to pay him, after a federal-court jury upheld his claims of trademark infringement by Nike and rejected the footwear and apparel firm’s legal defenses last month.

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The Norristown sports-clothes maker is one of a handful of specialized textile and clothing makers who continue to prosper here after the mass-market garment industry, once a major city employer, moved production overseas in the late 20th century. Another survivor is Garrixon, the Northeast Philadelphia high-end athletic shoe maker founded by John Lee, who also started the Ubiq and Atmos USA store chains.

Nathan says smaller shops like Sweat It Out and Garrixon are unusual phenomena in Philly these days. A textile engineer, he moved to the city from Israel in 1972 to study at what was then Philadelphia College of Textiles & Science (now part of Jefferson University), back when the city was still what he called America’s “textile capital.” Manufacturing has gone but the city has remained a center of fabric design and innovation.

Nathan founded Lontex in 1989 to develop high-end sports underwater and sweats, using his own trademarked Coolmax fabric, with Lycra mixed in. Lontex garments offer what Nathan calls Cool Compression, fabric designed to grip and stretch along muscles, spreading pressure away from injuries or damage-prone points. His company registered the Cool Compression trademark in 2008.

“NFL, NHL, all the Major League Baseball teams, NBA, every athletic trainer knows them,” he said.

But in a 2019 complaint filed in federal court in Philadelphia, Nathan’s company alleged its global rival Nike was hijacking sales by marketing its own similar gear promising “cool compression.” The complaint alleged three counts of trademark infringement under the federal Lanham Act, which governs trademarks, and two counts under state trademark law.

In its defense, Nike claimed Lontex had stopped using the “Cool Compression” description in its advertising several years before, and had even tried to sell the trademarked phrase. It alleged Lontex had “abandoned” that description for its sportswear.

Nike lawyers also denied that Nike was really using “Cool Compression” as a “product mark” and complained that Lontex was presenting Nike’s advertising “out of context” to make its case. Nike officials didn’t return calls seeking comment on the company’s case.

But Nathan’s lawyers argued that the company continued to use “Cool Compression” on its labels.

A parade of professional athletic trainers stated that Nike’s advertising and product claims were clearly directed at Lontex products.

The jury agreed, and entered an initial judgment against Nike for $507,000, plus additional damages to be determined next by U.S. District Judge Michael Baylson, who oversaw the trial.

Nathan’s lawyers — Michael Schwartz at Troutman Pepper Hamilton Sanders’ Philadelphia office and Ben Wagner at its San Diego office — said professional sports trainers were instrumental to their case.

Chris Peduzzi, who retired as head athletic trainer for the Philadelphia Eagles after their Super Bowl win in 2018, gave the court a statement that his players were longtime fans of Nathan’s “Cool Compression” gear..

Starting when he was assistant trainer in 2008, Peduzzi said, “I had my players consistently use Lontex’s Sweat It out products, because I have observed it to be very effective at rehabilitation, exercise and recovery.”

He said Cool Compression products give athletes a “unique stretch,” and he made sure the Eagles always had them in stock.

To be sure, the Eagles also used Nike’s gear, which in recent years that company also advertised as offering “Cool Compression.”

But “Nike is using Lontex’s Cool Compression technology” in its own rival garments, including some sold through the outdoor-wear cooperative REI, Peduzzi concluded.

“I had many of my players use Lontex’s Sweat It Out products,” added Brian Ball, head trainer for the Chicago White Sox, in a 2020 declaration to the court. He said Nathan always said the gear provided “Cool Compression,” and demonstrated how it worked each time the White Sox came to play the Phillies, showing how it “stretched differently” from rival products. Among players, the garments “had a reputation for actually working.”

The White Sox have bought and used Cool Compression clothing since at least 2011. Ball also concluded that in recent years, Nike has been selling gear that appears to be using Lontex’s Cool Compression.

Mark Smith, head athletic trainer for the Baltimore Ravens from 2011 to 2018, said he, too, “had my players consistently use Lontex’s Sweat It Out products,” with the “Cool Compression” label, “because I have observed them to be very effective” at helping rehabilitate injuries, he told the court,

He said the Ravens have bought Nathan’s clothes “every year since at least 2006″ — before he was head trainer. He, too, said he believes Nike is using Nathan’s technology in its own recent “compression” garments, including items sold at Dick’s Sporting Goods as well as those sold directly by Nike.

“They left no doubt in the jury’s mind,” said lawyer Wagner. “The jury agreed to award reasonable royalties and punitive damages,” which he said is rare in trademark decisions. “What remains for the judge to decide is whether and how much of Nike’s profits to disgorge.”

According to testimony, Nike and retailers who sell its products collected $95 million in profits that could be tied to its “cool compression” claims. Some of that, if it ends up with Nathan’s company, could prove a useful endorsement capping his career.