In a video, Matt Powell of industry-research firm NPD explains exactly how they're doing so.
First off, millennials aren't into golf. That could be terrible news for the industry as a whole.
"From the golf industry statistics, we know that rounds are down, We know that millennials are not picking up the game, and boomers are aging out. The game is in decline," he says.
Another category that's seeing damage from millennials is the road-cycling industry.
Though millennials may be enamored with fitness classes (like SoulCycle, for instance), biking on the road hasn't captured them as much.
It requires special apparel that you can only use when you're doing that particular activity, and Powell says that "they [millennials] want something that's much more versatile that they can use for multipurposes."
One category in the sporting industry they do like, though, is camping. Powell says it's "much more lighthearted." He explains how people can use camping equipment in a variety of places, like in their own backyards.
You can watch the video is below.