What is [SML] Training System This post aims to give a general introduction to Second Life resident new and old who have yet to try the SML Gym Training System. The SML Training System in Second Life is one of the most popular gym and bodybuilding roleplay systems available in-world. Built around a HUD-based workout and progression system, SML (often called SML Training) is a HUD-based workout system where residents train with interactive gym equipment to increase strength,