Full-Body vs. Split: Science Debunks a Common Myth About Muscle Growth!

There are people who go to the gym three times a week, work out their entire body each time, and leave satisfied. And then there are those who have a specific muscle group targeted for each day: Monday—chest, Tuesday—back, Wednesday—legs, and so on. Both groups often believe that their approach is the best for building muscle.

But who’s right? Do you have to train each muscle group separately for it to actually grow? Or can you achieve similar results by doing full-body workouts several times a week? The answer came from an extensive scientific analysis conducted in 2024. And its conclusions may surprise especially those who consider the classic split routine an essential part of serious bodybuilding.

Article Contents:

• Full-body or split? Researchers compared 392 exercisers
• Why does your workout split matter so little?
• Full-body vs. split: Which system is better for you?
• What if you’re an advanced bodybuilder?
• Want to build muscle? Don’t forget what happens outside the gym
• So how do you design a workout that actually makes your muscles grow?
• Maybe we’ve been asking the wrong question all along

Full-body or split? Researchers compared 392 exercisers

In 2024, researchers published a systematic review and meta-analysis in the Journal of Strength and Conditioning Research that included a total of 14 studies and 392 participants.

The goal was to determine whether splitting up your workout has a significant impact on muscle growth and strength development.

The researchers compared two popular approaches:

• Full-body: A workout in which you train most of the major muscle groups during a single session.
• Split: A training system in which you divide individual muscle groups across different days.

And the result? As long as the total weekly training volume was comparable, the researchers found no statistically significant differences in muscle growth or in the strength metrics they measured. Similar results were observed, for example, when evaluating the arm muscles, the quadriceps, and total lean body mass.

Does this mean that full-body training is just as good as split training? The available evidence suggests that both systems can yield similar results. However, this does not mean they are interchangeable under all circumstances. The decisive factor is, above all, how you structure your entire workout.

Why doesn’t the training split matter that much?

Imagine two athletes who want to build a bigger chest. The first follows a classic split routine. On Monday, he does nine working sets focused on the chest muscles and doesn’t train them directly for the rest of the week. The second uses a full-body routine. He works his chest on Monday, Wednesday, and Friday, doing three working sets each time.

By the end of the week, both have completed nine direct sets for the chest. And this brings us to an important principle.

Muscles don’t respond to the name of the training plan, but to the load we subject them to. For hypertrophy, sufficient mechanical stimulation, an appropriate training volume, and long-term progression are particularly important.

The difference may lie in how effectively you can complete each set. With a classic split, you do more work on a single muscle group during a single workout. However, fatigue can gradually build up, affecting your performance in subsequent sets. A full-body workout, on the other hand, allows you to spread the work over multiple days. This way, you can start each workout feeling more rested and focus on a specific muscle group more often.

That doesn’t mean, however, that a higher frequency automatically leads to greater muscle growth. If the weekly volume is similar, the results of both approaches can be comparable.

Full-Body vs. Split: Which System Is Better for You?

Although scientific studies haven’t identified a clear winner, both approaches have their practical advantages and limitations.

The table illustrates typical ways to use both methods, not strict rules. A split routine can target each muscle group multiple times a week, and full-body training can also be suitable for advanced athletes.

The most important factors, therefore, are how much time you can devote to training and how well you manage your recovery. If you can only make it to the gym three times a week, full-body training may be a very practical choice for you. That’s because you don’t have to set aside a separate day for each muscle group. On the other hand, if you work out five times a week and want to focus thoroughly on, say, your back, shoulders, or legs, a split routine can offer you greater flexibility.

What if you’re an advanced bodybuilder?

This is where the whole question gets more interesting.

Imagine a bodybuilder who needs to complete a high training volume for several muscle groups throughout the week. If they tried to cram all that work into three full-body sessions, the individual workouts could be very long and exhausting.

Splitting the muscle groups across multiple days, on the other hand, can allow them to better organize individual exercises, sets, and recovery. That’s why we often see various split variations among advanced bodybuilders. However, this doesn’t mean that the split itself has any special growth-promoting effect.

It is primarily a method of organizing training. Likewise, it is not true that full-body workouts are exclusively for beginners. Even an experienced athlete can benefit from full-body training if they can properly manage intensity, volume, and overall fatigue.

Scientific evidence, however, has its limitations. The studies included examined specific training programs and their participants, often over a relatively short period of time. We cannot, therefore, automatically assume the same results for all elite bodybuilders or when training volume is extremely high.

Want to build muscle? Don’t forget what happens outside the gym

You may have a perfectly designed split routine or a well-thought-out full-body program, but if you neglect your diet and recovery over the long term, you may limit your results. Muscles need sufficient energy and protein intake to support growth and maintain muscle mass.

If you have trouble meeting your daily protein intake through your regular diet, GymSupps XWhey Protein can be a practical supplement. It contains a combination of whey concentrate, isolate, and hydrolysate and can help you easily supplement your protein intake throughout the day.

For regular strength training, GymSupps Creatine Monohydrate may also be an interesting option. When taken at a daily dose of 3 grams, creatine enhances physical performance during consecutive short-term intervals of high-intensity exercise.

However, neither of these supplements will determine whether a full-body or split routine suits you better. The most important factors remain high-quality training, a balanced diet, and adequate rest. Dietary supplements are not a substitute for these.

So how do you design a workout that actually builds muscle?

If you’re thinking about changing your workout routine, you don’t need to look for complicated rules.

Start by figuring out how many times a week you can realistically work out.

• Two to three workouts a week: A full-body workout is usually a practical choice. During each session, you can include several basic exercises and work most of the major muscle groups.
• Four workouts a week: A split routine for the upper and lower body, for example, can work very well. This way, you’ll work each area twice a week.
• Five or more workouts per week: A split routine can help you distribute a larger volume of work and allow for a more targeted focus on specific muscle groups.

These recommendations aren’t hard and fast rules. It’s more important to stick to a few basic principles over the long term:

• Keep track of your weekly training volume. The number of high-quality working sets for each muscle group is more important than the name of the training system itself.
• Gradually increase the intensity. Aim to improve your working weights, number of repetitions, or form over the long term.
• Respect recovery. More training days do not automatically mean better results.
• Choose a system you can stick to. Even the best program won’t work if you don’t have the time or energy for it over the long term.

And if you’ve been making visible progress for several months, you don’t need to change your plan just because someone else online recommends a different system.

Maybe we’ve been asking the wrong question all along

Full-body or split? Which system builds bigger muscles? Scientific evidence shows that, under comparable conditions, both approaches can yield very similar results. That doesn’t mean, however, that how you train doesn’t matter. It simply means that dividing muscle groups across different days isn’t likely the decisive factor.

One person might achieve excellent results with three full-body workouts a week. Another might be just as successful using a well-designed split routine. And perhaps that’s the most important message of all this research.

The best training plan isn’t necessarily the most complicated one. It’s the one that allows you to train effectively, recover, and improve over the long term.

References:

• Ramos-Campo et al. (2024): Journal of Strength and Conditioning Research.
• Carneiro et al. (2024): European Journal of Sport Science.