"Our doctors are the official Chiropractic and Performance doctors for University of ___ Wildcats, 4 local high school football teams, the Youth Martial Arts Center and multiple top MMA fighters"
This is the kind of experience and credibility you want to build. Approach a local high school, community college, or university sports team and speak to the coach and the school about becoming the official team Chiropractor. Offer a substantial discount for chiropractic services to the coach, the team members, and the school Principal or Dean in exchange for allowing you to advertise that you are the official team Doctor. Make sure the school knows all of the services that you have to offer so they feel that this is an opportunity they can’t pass up, and explain the benefits that chiropractic care will have on the team members and their physical abilities.
You can then send out press releases to local media sources informing them of your partnership, and you can even spend a small amount of money to have a banner made to be displayed at games or create brochures and posters that show pictures of you working with affiliated patients.
TIP: Offer to provide the team members supplements or sports gear with your information on them, like a t-shirt, backpack, etc.