Which workout split? Count your days first

Ask which workout split to run and you'll get an argument: full body, upper/lower, push/pull/legs, a body part a day. Most of that argument skips the question that actually decides it. How many days a week can you train, every week, for months?

Start there, because the split is only how those days get divided. The research is on your side: when the weekly amount of training is matched, split and full-body routines build similar strength and muscle.¹ This page puts the three common splits side by side, says which fits two to six days, and walks through what the studies say about training each muscle once or twice a week. Never lifted at all? The first four weeks comes first; you don't need to choose a split to start.

What a workout split is

A split is the plan for which muscles or movements each session trains across your week. Three layouts are the common ones:

• Full body: every session trains the whole body, usually a squat, a hinge, a push and a pull, plus an extra or two.
• Upper/lower: sessions alternate between upper body (chest, back, shoulders, arms) and lower body (quads, hamstrings, glutes, calves).
• Push/pull/legs: three kinds of session. Push is chest, shoulders and triceps; pull is back and biceps; legs is the lower body. (A back workout and a leg day, written out.)

You'll also see the body-part split: chest one day, back the next, and so on. It trains each muscle once a week and usually runs five days or more, which is why this page sticks to the three above.

Full body vs upper/lower vs push/pull/legs

What a week looks like on each:

• Full body, three days: Monday, Wednesday and Friday, alternating two sessions (A, B, A, then B, A, B). The three-day dumbbell plan and the college workout routine are both written out this way.
• Upper/lower, four days: upper Monday, lower Tuesday, a day off, upper Thursday, lower Friday.
• Push/pull/legs, six days: push, pull, legs, push, pull, legs, one day off.

The trade is between days and focus. Full body asks for the fewest days, and a missed session costs the least, because the next one trains everything again. Upper/lower gives each half of the body a whole session, so there's room for more exercises per area. Push/pull/legs gives each session the narrowest job and needs the most days. Run it on three days and every muscle is trained once a week, with all of its sets in that one session.

Push/pull/legs or upper/lower?

Mostly a question of days: upper/lower fits four, push/pull/legs fits six, and run on those days both train each muscle twice a week. None of the studies on this page tests the two against each other directly. What they do show is that the layout matters much less than the sets you put in it.

Which split for your number of days

Two days: full body

Full body both days, with at least a day between them. An upper/lower split fits two days too, but then each muscle is trained once a week.

Three days: full body, or a rotation

Full body is the default: three sessions, each muscle three times a week, a day off between sessions. The other option is a rotation: upper, lower, upper one week and lower, upper, lower the next, so each half of the body gets three sessions every two weeks. If you came to me with three days a week, full body is where I'd usually start. Push/pull/legs fits three days on paper, but it trains each muscle once a week.

Four days: upper/lower

Upper/lower, twice each. Each muscle is trained twice a week and no session has to cover everything. Put the days off where your week has gaps; two training days in a row is normal on this split, because they train different halves.

Five or six days: push/pull/legs

Six days fits push/pull/legs exactly, each muscle twice a week. Five doesn't divide neatly: run push/pull/legs as a rolling rotation that carries on whatever the day of the week, or do upper/lower twice plus one full-body day. Either way, five or six days is a choice, not a requirement. How often to train covers picking the number itself.

Once or twice a week: what the research says

The common rule is to train each muscle at least twice a week. A 2016 meta-analysis of ten studies backs it: training a muscle more often was linked to more growth. Looking at studies that compared one to three days a week with the amount of training matched, the authors concluded that twice a week beat once, inferred that the major muscle groups should be trained at least twice a week to maximize growth, and left open whether three times beats two.²

A bigger update in 2019 changed the picture. With 25 studies, the same lead author and colleagues found no significant difference between training a muscle more or less often once the weekly volume was equated, and concluded that people can choose how often to train each muscle "based on personal preference". Where volume wasn't matched, more frequent training came out ahead, but the difference between once a week and three or more times was modest.³

Splits have been compared head to head as well. The 2024 meta-analysis mentioned above pooled 14 studies with 392 participants and found similar gains in bench press strength, lower-body strength and muscle size from split and full-body routines when volume was equated. Its conclusion: people can choose a routine "based on their personal preferences".¹

What does move the needle is weekly volume: how many sets each muscle gets in a week. A 2017 meta-analysis of 15 studies found a graded dose-response, with more weekly sets bringing more muscle growth.⁴ A meta-regression of 67 studies published in 2026 found that muscle size and strength both rise with weekly sets, with diminishing returns. In the same analysis, the effect of frequency on muscle size was compatible with being negligible, while strength did rise with frequency, again with diminishing returns.⁵

The American College of Sports Medicine's 2026 position stand, a review of 137 systematic reviews, lands in the same place. Training frequency, from one day a week to more than five, did not change muscle growth when total volume was equated, while ten or more sets per muscle group a week enhanced it. For strength, two or more sessions a week helped. Its primary recommendation is lifting with high effort at least twice a week, with all major muscle groups trained.⁶

So for muscle, the layout matters far less than the weekly sets. For strength, training a muscle on more days helps, with diminishing returns. Twice a week per muscle is still a sensible default: it matches the ACSM's at-least-twice-a-week recommendation, and spreading a muscle's sets over two sessions leaves fewer of them in any one session. The deciding question is still the one this page started with: which layout lets you do your sets every week?

How to switch splits without losing progress

Because the matched-volume studies find so little difference between layouts, what you protect when you switch is your weekly sets and your working weights, not the old schedule.

1. Count your weekly sets per muscle before you switch, and land the new split in the same range. Three full-body days with three sets of a squat is nine sets a week; two lower days with a squat and a lunge at two sets each is eight. Close enough.
2. Keep the lifts you're progressing on, at the weights in your logbook. A new split is not a reason to change every exercise.
3. Start any new exercise a little light and add from there. New exercises can mean new soreness: soreness is common when a kind of activity is new to you, and one review of the research advises easing into new exercise over a week or two.⁷
4. Give it eight weeks before you judge it, and keep adding weight or reps the way you did before. (Progressive overload, explained.)

Common mistakes

• Choosing a split for the week you wish you had. A six-day plan run on three days trains each muscle once a week. Pick for the days you can repeat, and add a day later if it keeps turning up free.
• Skipping the missed day. On a split, a missed session is a missed muscle. Do the session you missed next, not the one the calendar says. Traveling? Run full body on the road.
• Counting sessions instead of sets. Two splits with the same hard sets per muscle are close to equal; a split that quietly halves them isn't. A hard set ends with only a few reps left in you. (Here's how to judge that.)
• Upper days that are all pushing. Every upper session needs a pull as well as a press, and a lower day needs the hamstrings and glutes as much as the quads. (How to do a pull-up and bench press form.)
• Switching splits every few weeks. The logbook is how you know a plan is working, and it only works if the plan holds still.
• Training through pain. Sharp pain is not soreness. If you have an injury, a medical condition or a medical question, talk to a doctor before you change how you train. I'm a fitness coach, not a doctor.

If you'd rather not plan it alone

A split on a web page doesn't know your week. Coaching is the version where your workouts live in the Trainerize app, the split is built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one. Coaching to build muscle explains how that works, and apply tells me about your week. Otherwise: count your days, pick the split that fits them, and put this week's sessions in your calendar.