Train each muscle group once a week or the whole body in a single session? The debate between advocates of the split and full-body has gone on for decades. The editorial team explains what the real difference is between these approaches and what meta-analyses say about them.
Two ways to organize the week
The split and full-body are not different sports or different exercises but different ways to distribute the load over the week. In full-body, each workout covers all the major muscle groups. In the split, the body is “divided” into parts, and each session is devoted to one or two muscle groups.
Classic examples of the split are “upper/lower,” “push/pull/legs,” or the bodybuilder's “one group per day,” when each muscle is trained once a week. Full-body is usually done 2–4 times a week, repeating the main movement patterns in each session.
The main parameter by which these approaches differ is the training frequency of each muscle group. In full-body, a muscle receives a stimulus 2–4 times a week; in the classic split, once; in an “upper/lower” or “push/pull/legs” split with 4–6 workouts, twice.
The second difference is the distribution of volume. In the split, one muscle group gets many sets per session; in full-body, the same weekly volume is distributed over several sessions in small portions.
Frequency, volume, and muscle protein synthesis
After a strength workout, muscle protein synthesis remains elevated for roughly 24–48 hours, although in trained people this period is shorter. Hence the hypothesis arose: if a muscle is trained more often, it will more frequently be in the “anabolic window,” and therefore grow better.
The meta-analysis by Schoenfeld, Ogborn, and Krieger (2016) showed that training each muscle group at least twice a week produces a greater gain in muscle mass than once a week. However, a later meta-analysis by the same authors (2019) clarified: when weekly volume is equalized, frequency does not substantially affect hypertrophy.
In other words, the main driver of growth is the total weekly volume of effective sets, as confirmed by the meta-analysis of Schoenfeld and colleagues (2017) on the “dose–response” relationship. Frequency is merely a convenient way to distribute this volume.
The study by Damas and colleagues (2016) also showed that at the start of training a significant part of protein synthesis goes toward repairing damage, and only after adaptation does it become linked to hypertrophy. This partly explains why a very large volume for one group in a single session has limited effectiveness.
What research says about strength
The picture for strength is similar. The meta-analysis by Grgic and colleagues (2018) showed that higher training frequency is associated with greater strength gains, but this effect is largely explained by greater total volume. When volume was equalized, the difference became insignificant.
At the same time, strength is also a skill. Frequent repetition of the basic movements (squat, bench press, deadlift) improves technique and neuromuscular coordination. That is why in strength sports athletes often perform the main exercises several times a week, even if they formally train by a split.
The study by Schoenfeld and colleagues (2015) on trained men compared a “one group per day” split with full-body at equal volume. Full-body produced somewhat better hypertrophy in some areas, while strength grew similarly. The authors emphasized the study's limitations and the need for further work.
So for strength and mass both approaches are effective if volume and progression are sufficient. The substantial differences lie rather in the area of practice and convenience.
Comparison table
We have summarized the key parameters in a single table.
| Parameter | Split | Full-body |
|---|---|---|
| Training of one group | 1–2 times a week | 2–4 times a week |
| Volume per group per session | Large | Moderate |
| Number of workouts a week | Usually 4–6 | Usually 2–4 |
| Session length | Moderate, focus on 1–2 groups | Can be longer due to many exercises |
| Missing a workout | A group may “drop out” for a week | Less critical |
| Local fatigue and soreness | Pronounced after a large volume | Moderate, but more frequent |
The table shows that the main differences concern organization: how many times to go to the gym, how long the session will be, and what happens if you miss a workout.
- The split lets you put a large volume into each group in one session.
- Full-body repeats movements more often and is more resilient to missed sessions.
- Hybrid schemes (“upper/lower,” “push/pull/legs” twice a week) combine the advantages of both.
It is also worth considering that in full-body the last exercises are performed in a state of general fatigue, so priority muscle groups are better placed at the start of the session or the order of exercises alternated between workouts.
In the split, meanwhile, it is important to ensure that a large volume in a single session does not lead to excessive soreness that would interfere with subsequent workouts.
Popular myths
Myth one: “Full-body is only for beginners.” In fact, full-body is effective for experienced athletes too, as studies on trained people confirm. It is used both in strength sports and in general physical preparation.
Myth two: “For big muscles you need a split like professional bodybuilders”. Professional athletes often have individual recovery characteristics, and their programs are not proof of the split's advantage for an ordinary person. Meta-analysis data do not confirm any advantage of a once-a-week frequency.
Myth three: “A muscle must be ‘finished off’ to failure, otherwise it will not grow”. A large volume in a single session has diminishing returns, and weekly volume can be effectively distributed over several sessions.
Myth four: “Frequency is the main thing.” The 2019 meta-analysis showed that at equal volume, frequency is not decisive. The main things are sufficient volume, progressive load, and recovery, as the ACSM (2009) emphasizes.
Editorial conclusions
The split and full-body differ primarily in the training frequency of each muscle group and the distribution of volume over the week. At equal weekly volume, both approaches provide similar gains in strength and muscle mass.
Training each muscle at least twice a week is a convenient guideline that is easy to implement both in full-body and in an “upper/lower” or “push/pull/legs” split.
The choice between them depends on your schedule, experience, goals, and personal preferences.
We have gathered practical recommendations on the choice in the article “Split vs Full-Body: What to Choose and for Whom.” We also recommend materials on strength training and CrossFit and on the protein requirement for gaining mass.
References
- Schoenfeld BJ, Ogborn D, Krieger JW. Effects of resistance training frequency on measures of muscle hypertrophy: a systematic review and meta-analysis. Sports Med. 2016;46(11):1689–1697.
- Schoenfeld BJ, Grgic J, Krieger J. How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. J Sports Sci. 2019;37(11):1286–1295.
- Grgic J, Schoenfeld BJ, Davies TB, et al. Effect of resistance training frequency on gains in muscular strength: a systematic review and meta-analysis. Sports Med. 2018;48(5):1207–1220.
- Schoenfeld BJ, Ratamess NA, Peterson MD, et al. Influence of resistance training frequency on muscular adaptations in well-trained men. J Strength Cond Res. 2015;29(7):1821–1829.
- Schoenfeld BJ, Ogborn D, Krieger JW. Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis. J Sports Sci. 2017;35(11):1073–1082.
- Damas F, Phillips SM, Libardi CA, et al. Resistance training-induced changes in integrated myofibrillar protein synthesis are related to hypertrophy only after attenuation of muscle damage. J Physiol. 2016;594(18):5209–5222.
- American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009;41(3):687–708.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
