Key takeaways
- An upper/lower split trains every muscle group twice a week across four sessions of roughly an hour.
- Twice-weekly frequency edges out once-weekly for hypertrophy and strength, though much of the advantage narrows once weekly set count is equated.
- Weekly set count has the clearest dose relationship in the hypertrophy literature, and four days makes that count easy to distribute.
- MV, MEV, MAV and MRV are Renaissance Periodization's coaching framework, not a trial result.
- The split is a scheduling device. Double progression and written numbers are what actually move the weight.
Four days a week is the point where a training week stops being a compromise. Two or three days forces you to cram every movement pattern into every session. Five or six days asks for a level of scheduling discipline most people do not have alongside a job. The upper/lower split sits between the two, and it is the most commonly recommended intermediate structure in strength training for a straightforward reason: it trains every muscle group twice a week, spreads the weekly work across four sessions that each fit inside an hour, and still leaves three days for the rest of your life.
What an upper/lower split actually is
The structure is exactly what the name says. You divide the body in half at the hips and alternate: an upper-body day, a lower-body day, a second upper-body day, a second lower-body day. Most people run it Monday, Tuesday, Thursday, Friday, which gives a rest day mid-week and two at the weekend, but any arrangement that avoids four consecutive training days works. Upper / Lower — 4 Day in the Method library is this structure written out, twelve weeks of it.
Each upper day covers four patterns: a horizontal press, a vertical press, a horizontal pull and a vertical pull, plus direct work for shoulders and arms. Each lower day covers a squat pattern, a hip hinge, a single-leg movement and calves. Because you see each half twice, you can make the two sessions different rather than identical: heavier and lower-rep on the first, higher-rep and more accessory-focused on the second. That is where the split earns its reputation. You get the frequency of a full-body plan and the exercise variety of a body-part split at the same time.
What it is not is a magic stimulus. A split is a scheduling device. It decides when the work happens, not whether the work is hard enough to matter. Every point below is really about the work, and the split is just the container that makes the work easy to fit in.
The frequency argument, stated honestly
The strongest case for four days is that it puts every muscle group on the schedule twice. When researchers pool the studies comparing training a muscle once a week against twice, the higher-frequency arrangement comes out modestly ahead for muscle growth (Schoenfeld et al., J Sports Sci 2019). For strength, the same pattern shows up across the frequency literature, with more frequent sessions favoured on average (Grgic et al., Sports Med 2018).
The honest caveat is that much of that advantage narrows once total weekly sets are held equal. Frequency is not a separate growth signal so much as a delivery mechanism. Splitting your weekly work across two sessions lets you do more of it well, because the tenth hard set of a session is rarely as good as the third. Two moderate sessions beat one long one mostly because the second half of a long one is fatigued, rushed and lower quality.
Where the weekly volume actually lands
Weekly set count is the variable with the clearest dose relationship in hypertrophy research: as weekly sets per muscle group rise, average growth rises with them, in a graded rather than all-or-nothing way (Schoenfeld et al., J Sports Sci 2017). That relationship is not infinite, and it flattens, but within the range most people train, more well-executed sets generally means more growth.
A note on terminology, because it gets misattributed constantly. The volume-landmark language you see everywhere online, MV, MEV, MAV and MRV, is Renaissance Periodization's coaching framework, developed by Mike Israetel. It is a planning model for organising a training block, not the output of a trial. The dose-response work above is the evidence for the general shape those landmarks describe. Treat the landmarks as a useful way to think about programming, and treat the research as the thing that supports the shape, and you will not misquote either.
In practice, four days makes weekly volume easy to distribute. Programming convention lands most lifters somewhere between ten and twenty hard sets per muscle group per week. On an upper/lower split, that is five to ten sets per muscle group per session, which is a comfortable session, not an endurance event.
The real reason four days works: it is the highest frequency most people will actually complete for a year. A six-day plan that you run for five weeks and abandon produces less than a four-day plan you finish twice. Adherence is a programming variable, not a character flaw.
Upper/lower versus full-body versus push/pull/legs
All three structures can be built to the same weekly volume. What differs is how the work is packaged and what breaks first when life interferes.
| Full body | Upper / lower | Push / pull / legs | |
|---|---|---|---|
| Days per week | 2 to 4 | 4 | 3 or 6 |
| Frequency per muscle | 2 to 4 times | Twice | Once at 3 days, twice at 6 |
| Session length | Long, everything each time | Moderate, roughly an hour | Shortest per session |
| Cost of a missed day | Low, each day repeats | Moderate, one half loses a session | High at six days, the week unravels |
| Best suited to | Beginners, busy weeks | Intermediates with four reliable days | Advanced lifters chasing volume |
The written versions of all three sit in the Method library: Upper / Lower (4x) for the split described here, Full Body (4x) if you would rather touch everything every session, and Push / Pull / Legs (6x) if you genuinely have six days.
How to build the four sessions
A workable template, before you change anything:
- Upper A (heavier): barbell bench or incline press, barbell row, overhead press, lat pulldown or pull-up, one biceps and one triceps movement
- Lower A (heavier): back squat, Romanian deadlift, split squat, calf raise, loaded carry or core
- Upper B (higher rep): dumbbell press variation, chest-supported row, lateral raise, cable pulldown, arms
- Lower B (higher rep): hinge or hip thrust led, leg press or hack squat, leg curl, calves, core
Three to four sets per exercise, five to eight reps on the heavier days and eight to fifteen on the higher-rep days. Keep the first movement of each session consistent for at least eight weeks so you have a number to beat. Rotate accessories if you want variety; do not rotate the lifts you are measuring progress on.
How hard each set needs to be
Set quality decides whether the structure matters. Sets taken close to the point where form breaks down produce more growth than comfortable ones, and the evidence points toward proximity to failure mattering more for hypertrophy than for strength (Refalo et al., Sports Med 2023). That does not mean grinding every set to failure. On compound lifts, stopping with one to three reps in reserve keeps fatigue manageable across four sessions; on isolation work, going closer to the limit costs you very little.
Progressing it without redesigning it
The most common mistake on an upper/lower split is treating it as a menu to be rewritten every few weeks. Structure is not the thing that stalls, progression is. Use double progression: work within a rep range, add reps until you hit the top of the range on every set, then add weight and drop back to the bottom of the range. Write it down. If you cannot say what you lifted four weeks ago, you are not progressing, you are attending.
Plan a lighter week roughly every sixth to eighth week, or whenever the same load starts feeling heavier two sessions running. That is not lost time, it is what makes the following block possible.
When four days is the wrong answer
If you can only commit to two or three days, do not run a four-day plan at half attendance. A properly built two- or three-day full-body plan beats a half-completed four-day one, every time. If you are new to lifting, the priority is technique and consistency, not split design. And if you have four days but no reliable equipment, the split still works, the exercise list just changes. The Method library has a written version for each of those situations.
Bottom line
The upper/lower split is popular because it is the best compromise available to someone with four training days: every muscle group twice a week, sessions that finish in an hour, a manageable weekly set count, and enough exercise variety that you do not resent it by week six. Nothing about it is clever. It works because it is easy to do properly for a long time, and the plans that get done are the ones that produce results.
Educational content, not medical advice. Individual results vary.
