Different strength training authors from Ellington Darden and Mike Mentzer to Dorian Yates and Gordon LaVelle have called their system HIT, with each individual having credited Arthur Jones for the formulation of its basic tenet principles. However, there has never been a clear and consistent guideline on how to utilize HIT. Darden advocated full body routines, while Yates recommended to split the workouts into four different sessions a week. Mentzer believed that no more than one set to muscular failure per body part was all that was required, yet Yates and LaVelle believed that more than one exercise per body part is necessary to get complete development as a bodybuilder.