About Split Training Workout Routines. Fitness experts recommend starting with bigger muscle groups such as legs, chest and back and continue with smaller ones like abs, biceps, triceps, shoulders, etc. The best way is separating the upper body and lower body. The benefit of full body training is that you can achieve more in a shorter amount of time. By utilising compound exercises – exercises that target more than one body part at a time – you can work more muscle groups at once.