<P> Few studies have investigated training for men, however, training in women has been shown to exercise behavior patterns, improve perceptual benefit - to - concern ratio for exercise (decisional balance), and increase confidence to choose exercise in the face of other time demands (scheduling self - efficacy). Personal training results in higher strength, higher workout intensities, and higher perceived exertion during exercise in women . Although women working with personal trainers do self - select heavier loads than women who did not, the loads used are still below recommended training load percentages . </P> <P> The profession is generally not restricted by venue, and personal trainers may work in fitness facilities, in their personal homes, in client homes, over live video (also called "virtual personal trainers"), or outdoors . Almost all personal trainers and group exercise instructors work in physical fitness facilities, health clubs, and fitness centers located in the amusement and recreation industry or in civic and social organizations . Personal training is not regulated in any jurisdiction in the United States except for Washington D.C. which adopted registration requirements for personal fitness trainers in February 2014 . </P> <P> Personal trainers may specialize in a certain training type, training philosophy, performance type, exercise modality, or client population . In general, most personal trainers develop exercise prescription plans for aerobic exercise, resistance exercise, and / or flexibility training . With aerobic exercise prescription, personal trainers determine the type of exercise, duration of exercise, and frequency of exercise . For resistance exercise prescription, the type of exercise, total session volume, rest period, frequency, and intensity are determined . Personal trainers may also be involved in prescription of stretching routines or other approaches . Personal trainers help clients to perform exercises with correct technique, minimising the risk of injury and maximising results . While some discuss nutrition, ergogenic supplementation, and spiritual practices with clients, there is debate within the industry as to whether it fits within their scope of practice and training qualifications . </P> <P> Personal trainer accreditation is a process that provides certification of competency as a personal trainer . Qualification standards for personal trainers vary between countries . </P>

When did personal trainers first enter the fitness industry