Athlete sub-profiles are visible in the "Households" of the account owner and any additional Guardians.
Locate and click on the Athlete's sub-profile. Click the three dots > View Profile.
On the right side of the screen, view accounts listed under the Permissions header.
If viewing as an Account Owner, your name will be labeled Account Owner, and you can add Guardians using the +Add button.
If viewing as a Guardian, the account owner's name appears first, and yours is labeled as Parent/Guardian - "Parent/Guardian" cannot add additional Guardians.