Hey *|CONTACT.FIRSTNAME|*,

Hope you're doing awesome! I'm [Your Name] from [Your Company], and I noticed you're into [specific fitness aspect]—cool stuff !
I've got some pretty exciting ideas that could seriously amp up your fitness routine. How about we catch up with a quick call this week to chat about it? I swear it won't eat up more than 15 minutes of your time. Let me know when you're free, and we can make it happen!

Warm regards,
[Your Full Name]