4 Day Split Workout Routine for Lean Muscle

4 Day Split Workout

Four days per week – that’s all it takes to reap the full benefits of resistance training. A 4 day split workout routine for lean muscle is all you need to build a lean, muscular physique.

While prevailing wisdom suggests that the more we do, the better our results are, there comes the point of diminishing returns.

And unless your goal is competitive bodybuilding, you don’t need more than two to four days a week in the gym. You can get very lean and hard with two or four days a week of resistance training.

To that end, we’ve put together a 4-day split workout routine for lean muscle gains. Here is everything you need to know about it:

Your 4-Day Split Workout Routine For Lean Muscle Gains

Each training week consists of two A workouts and two B workouts. 

Each week, you’ll do two successive workouts – A and B – then take a day off, and have two more workouts.

For example, your training week might look like this:

  • Monday – A-day Workout
  • Tuesday – B-day Workout
  • Wednesday – Rest Day
  • Thursday – A-day Workout
  • Friday – B-day Workout
Dumbbell Workouts

A-day Workout

  • Chest
  • Shoulders
  • Triceps 
  • Legs (can be done on A or B days)

B-day Workout

  • Back
  • Biceps
  • Abs
  • Legs (can be done on A or B days)

How You Do These Workouts Is Vitally Important

The goal of each workout should be to train your large muscles first (chest and back, for example), and progressively move to isolation work where you specifically target the smaller muscles – biceps, triceps, shoulders, and abs.

To avoid burnout and severe muscle soreness in the beginning, make each workout about 20-30 minutes long. That is all you need to properly and sufficiently workout your muscles.

You can structure each workout like this:

  1. Start with some dynamic stretching to warm up your body. This is key to avoid injury, especially as you get a bit older.
  2. Do about 5 minutes of cardio on a treadmill, bike, jogging in place, jumping rope, or elliptical trainer.
  3. Do 20 minutes of resistance training.
  4. Finish the workout with 5-10 minutes of HIIT on the treadmill or bike. HIIT is more advanced, so make sure to do your research on HIIT.


Sample A Day Workout and B Day Workout

A Day: Chest, Shoulders, Triceps, Legs

ExerciseMuscle GroupSetsReps
Push upsChest36-12
Bench Push upsChest36-12
Dumbbell Side RaisesShoulders36-12
Seated Dumbbell PressShoulders36-12
Dumbbell KickbacksTriceps36-12
Tricep ExtensionsTriceps36-12
Bench DipsTriceps26-12
Body SquatsLegs36-12

B Day: Back, Biceps, Abs, Legs

ExerciseMuscle GroupSetsReps
One-Arm RowsBack46-12
Bent Over Side RaisesBack46-12
Alternating Dumbbell CurlsBiceps36-12
Concentration CurlsBiceps36-12
Lying Leg RaisesAbs36-12
Front LungesLegs315-20

Things That Can Make or Break Your Lean Muscle Gains

Muscle growth is an intricate process, and the devil is often in the details. 

So, here are a few final considerations to keep in mind:

  1. To build muscle mass, you need to do resistance training, and your workouts need to be as challenging as your experience allows. Do two to three sets for each muscle, and aim for six to twelve reps per set. (1)
  2. Since lifting is inherently stressful to the body, you need to provide your muscles with protein as soon as you can. So, have a protein shake within 30 minutes of finishing a workout – that will prevent muscle loss and help you kickstart the recovery process. It’s also a really nice workout reward!
  3. Though often overlooked, hydration plays a huge role in our athletic performance and training results. So, make sure to drink enough liquids every day, especially on your workout days, as that can play a huge role in your overall results. Shoot for 8-12 glasses of water each day.
  4. According to statistics, a whopping 75 percent of Americans are overweight or obese. To avoid this, do a bit of cardio every day, including on your workout days. (2)

Doing cardio around your resistance training is a great way to burn extra calories, prevent unwanted fat gain, and still build lean muscle with the resistance training.

Chest Workout to Build Pecs

4 Day Split is Simple and Effective

So, your 4-day split workout routine for lean muscle gain is simple, but also effective. The key is the long game! You have to be consistent, and make it part of your DNA. Cement it into your weekly routine, and rarely miss a week.

As you can probably imagine, this routine is incredibly customizable, and you can make it work in numerous different ways. 

What matters most is that you enjoy the process, create a schedule you can follow, and push yourself hard enough. And if you only can commit to 3 days a week for your workouts, check our 3-day a week workout plan.

Here is some more info on workouts for every preference and muscle group:

Click to see other lean muscle-building workouts, and see our leg workout videos. Also check the powerhouse benefits of superset workouts.

David Williams

David Williams

A diet and fitness enthusiast, David is an ex-Army Airborne Ranger and Infantry soldier with decades of fitness and wellness experience. A West Point graduate with a degree in engineering, he focuses on technical research related to fitness, nutrition, and wellness. He loves the beach and working out, and spending time with his wife and daughters.

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  1. O’Connor, A. (n.d.). How to Get Strong. The New York Times.
  2. Norton, A. (2018). U.S. Obesity Rates Rising Again. WebMD. https://www.webmd.com/diet/obesity/news/20180612/us-obesity-rates-rising-again#1.

Click to see our medical disclosure.