Lululemon and Victoria's Secret are in danger of 'entering the death throes of the uncool'

Is this end of the athleisure?

Jan Rogers Kniffen, CEO of consulting firm J. Rogers Kniffen WWE, believes that the trend is on its way out - and that's terrifying news for companies like Lululemon.

"I think athleisure is rolling over for fall and its growth rate will dramatically slow, and then stall out," he wrote on retail blog The Robin Report.

"I am hearing people on the streets say that athleisure is the new normal, perhaps the best indicator any trend has peaked, is starting to plateau, then lose ground," he wrote.

The upcoming move away from athleisure probably won't hurt powerhouse brands like Nike and Under Armour because their business is more driven by athletic shoes and performance wear rather than fashion trends.

Kniffen believes Kate Spade and Coach will benefit as women move away from athleisure and need to purchase a new set of items.

"Women are going to need a whole new portfolio of accessories appropriate for non-athleisure style," he wrote.

Kinffer explains that brands that could suffer are ones that have invested heavily in female-specific athleisure apparel, like Victoria's Secret's VSX brand.

He also pointed to American Eagle lingerie brand Aerie as an example of a company that could be in trouble because it is known for its casual-wear.

Though Kniffer can't confirm that athleisure is over, he did write that he "[predicts] this trend is entering the death throes of the uncool."

There already signs, though, that athleisure brands could be troubled.

Both Nike and Under Armour have faced some issues in recent quarters.

And, Lululemon founder and former Chip Wilson told Business Insider that he believes the trend is being replaced by edgier designs.

Still, a lot of people - like teens - love athleisure, although if Instagram can dictates the rapid pace of the how trends move, then it's fair to guess than teens can fall out of love with a style just as quickly as they can become enamored with it.

For the full Robin Report post, click here.