Vessel was traveling up river, thru rough rapids, hit a rapid, passenger jammed down into his seat then twisted out of his seat onto the floor of the vessel.  He complained of back pain.  EMTs met the vessel, and transported the victim to the local medical center where they examined him, then decided to take him to the hospital in a larger city.  They admitted the victim and ran extensive tests, the victims back had a strain.
King Hill                     