Discussion, generally of an in-universe nature, regarding any aspect of the franchise (including movies, spin-offs, etc.) such as: techniques, character relationships, internal back-history, its universe, and more.
Gohan's age is approximately 47 in AGE 804. His research probably revolved around understanding ki on an applicable, technical, and historical level, among other things he may have detailed about. There's a difference between shooting a basketball and knowing how to shoot a basketball effectively, to use that for analogy.