UPPER/LOWER SPLIT! These 4 workouts are tough, but a lot of fun as well. They'll get the job done with helping you pack on some muscle, and you'll be able to get plenty of rest as well. The 4 day split is broken up into 2 upper body days as well as 2 lower body days, with a strength day and a hypertrophy day for each. I've realized that my recovery hasn't been so great. So for the next few months, I'm going to follow this 4 day upper/lower split to see where it takes me.