Once you look like Ronnie Coleman, then you can start dedicating an entire workout to your triceps. Until then, your focus is on gaining muscle and loosing body fat. Working on only one muscle group a day and using isolation exercises will not catalyze the metabolic and hormonal changes needed to dramatically alter your body composition. Whole-Body, 2-Day and 3-day split routines allow you to hit big muscle groups multiple times per week (using key compound exercises like such as squats, deadlifts, bench & pull-ups).