Let’s face it—working out is no longer just about breaking a sweat; it’s about strategy. Whether you’re aiming for a sculpted physique or just looking to bulk up, understanding the science behind your workout split is crucial. But with so many workout routines floating around, how do you pick the smartest one for building muscle? Don’t worry; we’ve got you covered.
And to build muscle you need to choose the correct type of training for you. You have to train smart.
And training smart is what Jeremy Ethier is known for and who we admire for bringing us the smartest workout routine to build muscle in 2025. Jeremy Ethier is a fitness enthusiast, certified kinesiologist, co-founder of Built With Science, and the creator of the fitness-focused YouTube channel “Jeremy Ethier.” He is known for providing evidence-based fitness and training advice, backed by scientific research. Jeremy shares workout routines, exercise tutorials, and nutrition tips to help individuals achieve their fitness goals. His content often emphasizes the importance of proper form, effective workout strategies, and understanding the science behind fitness practices
In this guide, we’ll explore seven popular workout splits, ranking them from the most effective to those that might just be wasting your time. Plus, we’ll toss in some science-backed insights to help you decide which routine works best for your goals in 2025. By the end of this, you’ll know how to maximise gains while keeping your gym time efficient.
How Was It Measured the Best Workout Splits
Before we jump into the rankings, let’s explain what separates the champs from the chumps: the Hypertrophy Score. This score is based on two factors:
- Frequency: How often you train a muscle group each week.
- Volume: The total number of sets per muscle per week.
The best workout split strikes the perfect balance between these two. According to a predictive growth equation developed with the help of PhD researcher Eric Trexler, here’s how the routines stack up.
1. The 5-Day Full-Body Split
- Hypertrophy Score: 10.0
The 5-Day Full-Body Split is a game-changer for advanced lifters. Each workout targets all major muscle groups, but in smaller doses spread across the week. This allows you to train each muscle five times weekly without overloading any single session.
Why It Works:
- Every workout stimulates muscle protein synthesis, ensuring your muscles are consistently signalled to grow.
- Advanced lifters, whose muscle recovery windows are shorter, benefit the most as it prevents “dead zones” where muscles aren’t stimulated.
What Science Says: A 2019 study comparing a 5-day full-body split to a traditional bro split found that full-body training led to more muscle growth across all measured areas. The frequent stimulation was the winning factor.
Drawbacks:
- It requires precise planning to manage fatigue and recovery.
- You’ll need to rotate the exercises for each muscle group to avoid overtraining specific movements.
Clik here to view.
This routine is best for seasoned gym-goers who know how to manage their recovery and balance intensity.
The Best Full Body Workouts: Beginner, Intermediate & Advanced
2. The 6-Day Push/Pull/Legs Split
- Hypertrophy Score: 9.7
The 6-Day Push/Pull/Legs Split is an intense option for those with time to spare and the passion to train six days a week. With two full cycles of push (chest, shoulders, triceps), pull (back, biceps), and legs, this split allows for high weekly volume.
Why It’s Popular:
- The structure ensures you hit each muscle twice weekly, aligning perfectly with research showing this frequency supports optimal growth.
- The additional volume is great for building muscle, especially for intermediate to advanced lifters.
What to Watch Out For:
- Overtraining is a risk, especially if you don’t manage recovery or sleep.
- For those with less time or a busy schedule, this may feel more like a grind than a lifestyle.
If you love spending time in the gym and don’t mind the commitment, this split could be your ticket to serious gains.
3. Upper/Lower/Push/Pull/Legs (5 Days)
- Hypertrophy Score: 9.0
The Upper/Lower/Push/Pull/Legs Split is a hybrid approach combining the volume of a 5-day plan with the balance of training different muscle groups. Over five days, this split ensures that each muscle group gets both frequency and variety.
Clik here to view.
Source: Scott Webb / PexelsWhy It Stands Out:
- Allows you to maintain higher training volume than a 3-day or 4-day split while keeping recovery manageable.
- The structured rotation ensures no muscle group is neglected.
Example Week:
- Monday: Upper Body
- Tuesday: Lower Body
- Wednesday: Push
- Thursday: Pull
- Friday: Legs
This routine is ideal for lifters who want a focused but comprehensive plan that doesn’t stretch into six days of gym time.
4. The 4-Day Upper/Lower Split
- Hypertrophy Score: 8.4
The 4-Day Upper/Lower Split is a masterclass in efficiency. Perfect for balancing gym time with a busy schedule, this split gives you a solid mix of frequency and volume by targeting upper and lower body twice weekly.
What Makes It Great:
- It’s practical: you train four days and recover on three.
- Despite fewer sessions, you can still hit optimal weekly volume, making it almost as effective as higher-frequency splits.
Clik here to view.
Who Should Use It:
- Beginners moving into intermediate territory.
- Lifters looking to maintain muscle with a slightly lighter gym commitment.
Pair this with consistent progressive overload, and you’ll see gains while enjoying a sustainable gym schedule.
5. The 3-Day Full-Body Split
- Hypertrophy Score: 8.1
The 3-Day Full-Body Split is a staple for beginners and busy professionals. Each session works all major muscle groups, ensuring no area is left behind.
Why It Works:
- Training each muscle three times weekly maximises growth for those starting out.
- Simplicity: fewer sessions mean less decision fatigue and better consistency.
Clik here to view.
Source: RehbandExample Schedule:
- Monday: Full Body (squats, bench press, pull-ups)
- Wednesday: Full Body (deadlifts, overhead press, rows)
- Friday: Full Body (lunges, incline press, chin-ups)
Beginners should prioritise mastering form and focusing on compound lifts before worrying about adding volume or variety.
6. The 5-Day Bro Split
- Hypertrophy Score: 8.8
Ah, the Bro Split—the classic bodybuilding routine. With each day dedicated to one muscle group, this split is all about focus and intensity.
Clik here to view.
Why It’s Still Popular:
- Allows you to exhaust each muscle group completely with high volume.
- Favoured by bodybuilders looking to sculpt each muscle in detail.
The Downside:
- You’re only hitting each muscle once weekly, which can limit growth if you’re not piling on sufficient weekly volume.
- The potential for “junk volume” arises—those late-workout sets where fatigue limits the effectiveness of your training.
It’s a fun split for advanced lifters but often less efficient than modern alternatives.
Differences Between Training for Size and for Strength
7. The 3-Day Push/Pull/Legs Split
- Hypertrophy Score: 6.7
The 3-Day Push/Pull/Legs Split is a minimalistic approach to training. By spreading your training across three focused days, you hit each muscle group once per week.
Why It Can Work:
- It’s simple and easy to follow, perfect for those new to splits.
- Can be adjusted for busy weeks when fewer training days are possible.
Clik here to view.
Why It Falls Short:
- Research shows that training each muscle more frequently (twice or three times weekly) leads to better growth.
Use this as a fallback when life gets hectic, but don’t rely on it as your primary strategy for growth.
Adding the Time-Efficiency Factor
Time is a precious commodity, and not all splits are created equal in terms of efficiency. The best workout split isn’t just about maximum hypertrophy—it’s about how much progress you can make in the time you have.
For most people, the 4-Day Upper/Lower Split strikes the perfect balance. It delivers 85% of the gains of the 5-Day Full-Body Split but requires 30% less time in the gym. This is crucial for busy professionals or those who need flexibility in their routines.
Additionally, shorter workouts like those in a 3-Day Full-Body Split can also fit into packed schedules, ensuring you don’t miss your fitness goals due to lack of time.
Key Takeaways from 2025 Muscle Science
Clik here to view.
- Train Smarter, Not Harder: Frequency and volume are your muscle-building MVPs.
- Adapt to Your Goals: Beginners might thrive on full-body splits, while advanced lifters can maximise growth with high-frequency routines.
- Don’t Overlook Recovery: Your muscles grow during rest, not in the gym.
Build Your Perfect Routine
The smartest workout routine is one that aligns with your lifestyle, fitness level, and goals. Here’s how to build yours:
- Define Your Goals: Do you want more muscle mass, strength, or balance between the two?
- Assess Your Availability: Choose a split that fits your schedule. If you can’t commit to six days, don’t force it.
- Start with a Base: Beginners can thrive with a 3-Day Full-Body Split, while intermediates may find the 4-Day Upper/Lower Split more effective. Advanced lifters should explore high-frequency options like the 5-Day Full-Body Split.
- Track Progress: Log your lifts and adjust volume or intensity as needed.
- Prioritise Recovery: Sleep, nutrition, and rest days are as important as the training itself.
Remember, consistency beats intensity over the long haul. Tailor your routine to your needs and watch your progress soar. Image may be NSFW.
Clik here to view.
10 Tips to Build Muscle as Quickly as Possible
This content is originated from https://www.boxrox.com your Online Magazine for Competitive Fitness.