Everyone responds differently depending on genetics. Some guys have what I call the 'freak' gene where they can work out 3 days and still have that swole and jacked look. This is the case with the guy I first started training with when I got to college. Kid was a monster no matter what we did, he was absolute animal looking. Very frustrating yet motivational when ur a frail freshmen like I was lol.
This being said, through all my endeavors in the gym over the last 4 years as a serious lifter as a college athlete I'm still a firm believer in muscle confusion. Training for strength i feel goes hand in hand with hypertrophy. I started 4 years ago at 5' 9" 160lbs and that's generous. Redshirted first year so I committed to just building mass. I blasted hard for 8 weeks and would take a week of high rep at bout 30% of my 1rm. Then get back to it hard and repeated the process. I would use pyramid schemes and drop sets with training til failure and had a 4 on 1 off split. Used mainly grneric lifts and compound lifts like squats and cleans.I ate like a beast and blew up. Got up to bout 173lbs in 8 months or so and granted some was fat but my bf% never surpassed 12% throughout.
The next couple of months I focused on my diet and strength gain. With compound lifts, extremity (bi's, tri's, calves, forearms) lifts, and core focus work. Would superset every major lift with a core exercise like toe touches, crunches, leg raises, planks. This really shredded Nd strengthened my full body because while activating my core in lifts, I was now focusing in on the abs an lower back a bit extra. Really shredded me up in the midsection. By the time I finished my sophomore year I was at 185lbs and 9% bf.
Hit my junior season in the spring at 180lbs and 8%bf. really went back to my hypertrophy training with low rep heavy compound lifts to failure. Currently in my senior year and weighed in yesterday at 187lbs and 9% bf.
Now with all this background rant...I digress, through my experiences with various trainers (one of which is former ny mets training staff and others that work with nfl guys) and my education in exercise science partially, I've learned that it's about muscle confusion through various splits, rep schemes, fast twitch slow twitch muscle training exercises and diet. IMO you must constantly change and alternate your workouts. As previously mentioned your muscles learn to adapt to exercises. Small variations in hand position or rotations, you can throw your muscle memory off enough to make gains. I try to change my muscle specific days weekly. If I hit chest on Monday and do incline press, and I do chest on Saturday I'll do incline flies instead of press or go to cable incline presses. Small changes like this can truly elevate your gains.
In addition, if your a strength guy like I am as a baseball guy, I recommend creating 5 day split with focus on compound lifts superseted with core exercises like med ball throws and what not to develop power. (clean to press with med ball twist throws) 30-45 seconds rest max.
If your looking for your size gains I recommend 4 day split with muscle concentration days with ab workouts 3 days a week. You'll see great gains in hypertrophy with the 5-8 rep range til failure. 1:00-1:30 rest be patient lol. Stay away from cardio exceeding 15 minutes. It can be catabolic to muscle growth.
Remember though, recovery is key. You must be open to really committing to off days and a week thrown in here and there where you lower your weight and raise your reps. Allows your muscles to recover and at the same time still confusing them.
Diet is another story And I could go on all night on that topic. Quick recommendation though, cut the crap food, stay away from fried stuff, red & white meats, stick to water (1.5-2 gallons/day) and eat like a beast.
Eat clean, confuse your muscles, get creative, get 8 hours sleep, and mentally commit to your program and your goals and you will grow. Be patient. It's taken me 4 years to reach where I'm at now and I'm not content (but them again who ever is) It's taken countless guys years and decades to reach their goals. Work hard and believe in yourself and don't compare to others, your not competing against anyone except yourself. Take it one workout at a time and kill every one!
Disclaimer: I'm no professional in any field and only speak to my personal experiences and education. I'm just another guy trying to lend a hand to someone asking for help in this quest for beastlyness.
Enjoy the journey and never stop learning and adapting. Good luck man! Hope I helped and apologize for my long and unnecessary story. Hope some of it made sense.
*END Rant*