British sportswear brand Gymshark has taken legal action against popular fitness influencer Nathaniel Massiah, the Financial Times reports.

Gymshark, known for its appeal to millennial and Gen Z gym-goers, has applied for a High Court injunction in London to prevent Massiah, a 22-year-old powerlifter and influencer, from promoting competing brands.

The move comes after Massiah, who had been associated with Gymshark since the age of 17, began promoting YoungLA, a competitor brand, in December. This action, according to Gymshark’s lawyers, breached several clauses in his contract, including a three-month non-compete clause following the end of his agreement.

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Massiah’s legal team argues that the young influencer had limited time to prepare for the hearing and that the contracts were not negotiated on equal terms, given Gymshark’s substantial resources. They also raised concerns about the potential impact on other young athletes who might be under similar contractual obligations.

Gymshark, which has grown from a garage start-up in 2012 to a global brand with annual revenue exceeding £500m, defended its position. 

The company said that it had supported Massiah throughout his early career and that the contract terms were clear from the outset.