Mo. Rev. Stat. § 334.611
Notwithstanding any other provision of law to the contrary, any qualified physical therapist who is legally authorized to practice under the laws of another state may practice as a physical therapist in this state without examination by the board or payment of any fee if such practice consists solely of the provision of gratuitous services provided for a summer camp or teaching or participating in a continuing educational seminar for a period not to exceed fourteen days in any one calendar year. Nothing in sections 334.500 to 334.625 shall be construed to prohibit isolated or occasional gratuitous service to and treatment of the afflicted or to prohibit physical therapists from other nations, states, or territories from performing their duties for their respective teams or organizations during the course of their teams' or organizations' stay in this state.
§ 334.611, RSMo