Physical training instructor

Physical training instructor (PTI) is a term used for an instructor in physical fitness, primarily in the British Armed Forces and British police, as well as some other countries in the Commonwealth and elsewhere. == United Kingdom == In the British Army, specialist physical training instructors (PTIs) of the Royal Army Physical Training Corps are attached to individual units to oversee physical training and manage military gymnasiums.

Source: Wikipedia — Physical training instructor (CC BY-SA 4.0)