You've got a niche product so maybe find an influencer? One of the top rock climbing folks? I would also send a bunch of free trial stuff to the local rock climbing gyms maybe with an ad campaign.
Searching Amazon also seems to show that gymnastics and weigh lifting are a market as well.
You really want a strong brand. Shark tank might be an option too.
I was thinking along a similar line. There are popular rock climbing channels on YouTube. Some of these channels already include promotional or sponsored content. One option is to pay to include your product in a video ("sponsored by Chalk Rebels, get 20% off your first order with this exclusive discount code").
Or send them your products and ask if they would be willing to try and review your product, no strings attached. There may be a risk they may not like your product (hopefully not). Also, best to keep in mind that some proportion of subscribers to a climbing channel will not necessarily be climbers.
Most Subscribed Rock Climbing YouTube Channels (2017~2020):
The list of channels is in the description below the video:
Searching Amazon also seems to show that gymnastics and weigh lifting are a market as well.
You really want a strong brand. Shark tank might be an option too.