Is this for treatment of an injury or illness? Or just a preventive service or to improve athletic performance?
Think the scope of practice question is kind of a separate issue. Assuming these are allowed under their license, the CPT codes that represent these services are in the physical therapy section, so there are codes you can bill. But an athletic trainer isn't a provider type that you can credential, which means that under normal circumstances the services would have to be performed 'incident to' a physician. Commercial payers may or may not allow this. So I think I have to go back to my original answer and refer you to the specific payers for guidance on this.
You're in an unusual situation and if you're going to be billing this to a payer, your best bet is to be up-front and speak with them ahead of time so you and the payer both have a clear idea ahead of time and there isn't a surprise down the road after a lot of services have already been billed. Sorry not to be of more help. You might want to consider reaching out to a consultant or someone with specialized experienced in this area. We on this forum are mainly just coders.