My preferred exercise routine is a mix of HIIT, Instability, and Hypertrophy.
I do this routine 4 times a week from Monday to Thursday. I take Friday to Sunday off as rest and recovery days. This seems to work best with my work schedule and preferences.
I go to the gym after work in the evenings around 5:30PM and spend an hour there.
I start with a stretching and warm-up routine for about 5 minutes.
Then I get started with my weight training for the selected body parts for the day. These days I switch between the following body part splits.
Option 1: Monday - Chest, Tuesday - Legs, Wednesday - Shoulders, Thursday - Back with biceps and triceps workouts sprinkled in on each alternating days.
Option 2: Monday - Chest & Back, Tuesday - Legs and Shoulders, Wednesday - Arms, Thursday - Stability and core exercises.
The goal with this plan is to give each body part enough recovery time for the next time they are hit again. For each body part I start the routine with one of the major classics, like bench press, squats, deadlifts, shoulder press, weighted pull-ups, or barbell rows and then move on to other more specialized exercises.
The specialized exercises are means to introduce more intensity using techniques like double x-overload, triple x-overload, drop-sets, supersets, rest-pause, slow eccentrics and TORQ. These also cause additional metabolic stress and muscle damage and most importantly allow me to vary the types of workouts to keep things fresh and interesting.
Some of the workouts with which I use the above techniques are as follows.
Chest - Cable flyes, Dumbbell flyes
Shoulders - Front raise and Side raise with dumbbells
Back - Dumbbell rows, Cable pull
Legs - Dumbbell deadlifts, Leg presses
Arms - Cable curls
I like to keep a list of about 10 or more workouts for each body part to choose from so that I can switch between them if I get bored with one routine. I try to do a total of 15-20 sets combined with strength and intensity type workouts for each body part on a given day.
I end the workout with a 10 min. HIIT routine on the stationary bike, with fast biking alternating with normal speed biking. This really revs up my heart and gets blood flowing everywhere, with the added advantage of increased metabolism and fat loss even after the workout is long over. I usually cover about 3.5 miles in those 10 mins.