The problem: you have outgrown the question "which workout today?"
You have trained for a while. Maybe you followed a full-body plan from the last article, made progress, and now your sessions are getting long. Every workout has a squat, a hinge, a press, a row and a few extras, and by the last exercise you are tired and rushing. Or maybe you simply have four days a week and wonder whether those days should look different from each other.
This is where many people meet the upper / lower split. It is one of the most common program structures in gyms, coaching apps and printed plans. This article answers one question: what is an upper / lower split, what does it build, who is it for, and when would APEX choose it?
The simple answer
An upper / lower split divides your training into two kinds of session. Upper days train the push and pull movement families: chest, shoulders, upper back, lats and arms. Lower days train the squat, hinge, lunge and single-leg families: quads, glutes, hamstrings and calves, often with carries and trunk work.
Most commonly it runs on four days a week (for example upper, lower, rest, upper, lower), so each muscle and main pattern is trained about twice a week. That twice-weekly rhythm is its whole point. The split is not a special method. It is a way of spreading enough weekly volume into sessions you can do well, once a full-body session has become too long or too tiring to do well.
Why it matters
Article 43 explained that frequency mainly distributes your weekly work. Article 40 explained that volume, counted as hard sets per muscle per week, is a key driver of muscle growth. As your capacity grows, the volume you need to keep progressing usually rises. A full-body session can only hold so many hard sets before quality drops, the sessions run long and the last exercises become sets done tired and badly.
The upper / lower split solves that specific problem. By giving each session half the body, it lets you do more hard sets per muscle in each session while keeping session length reasonable and each muscle still trained about twice a week. That is the APEX test for any added complexity: it must solve a real programming problem. If you have no such problem yet, you may not need this split.
What the evidence says
The research layer is fairly clear on the parts that matter, and less clear on the parts people argue about.
- Frequency for muscle. A meta-analysis of resistance training frequency found that training each major muscle group at least twice a week produced more growth than training it once a week[1]. An upper / lower split on four days meets that frequency by design.
- Volume matters more than how it is split. A meta-analysis on frequency and strength found that when total weekly volume was equal, training frequency itself made little difference to strength gains[2]. In plain terms: the weekly dose matters most, and the split is a way to deliver it.
- More weekly sets, more growth, up to a point. A dose-response meta-analysis found a graded relationship between weekly sets per muscle and muscle growth[3]. This is why splits become useful as people need more volume than one session can comfortably hold.
- A recognised option for intermediate trainees. The American College of Sports Medicine position stand on resistance training progression describes upper / lower splits on about four days a week as one appropriate structure for intermediate trainees, alongside full-body training on three days[4].
What the evidence does not show is that upper / lower is superior to full-body or push / pull / legs when weekly volume and effort are matched. Studies comparing splits generally report small or no differences, though this research is limited in size and duration, so certainty is moderate rather than high. The honest conclusion: upper / lower is a sound, well-supported way to organise training, not a better way for everyone.
The APEX principle: structure follows the person
The coaching principle that follows from the evidence is simple. Choose the split that lets you deliver your needed weekly volume, at about twice a week per muscle, in sessions you can attend, recover from and do with quality. The APEX framework then asks the usual questions in order: who are you, what stage, what goal, how many days, what equipment, how do you recover? The split comes last. It never comes first.
How an upper / lower split actually works
The four-day version
This is the classic structure:
- Day 1: Upper A
- Day 2: Lower A
- Day 3: rest
- Day 4: Upper B
- Day 5: Lower B
- Days 6 and 7: rest or easy activity such as walking
The A and B days usually differ. Often one day leads with a horizontal push and pull (bench press, row) and the other with a vertical push and pull (overhead press, pulldown or pull-up). On lower days, one may lead with a squat pattern and the other with a hinge. This covers more of each movement family across the week without cramming everything into one session.
The rotating three-day version
If you have three days, you can rotate: week one is upper, lower, upper; week two is lower, upper, lower. Each half of the body gets three sessions every two weeks. It is a workable middle ground, though full-body three days a week is often simpler for the same schedule.
The two-day version
Two days a week (one upper, one lower) trains each muscle only once a week. This can work for maintenance or for someone who also does other training, but for most people with two days, full-body twice a week delivers better frequency. This is a good example of a split being chosen for the wrong reason.
Inside a session
Everything from the programming articles (editorial phase 5 of this series) still applies. Put the most important and most skill-demanding lift first (article 48). Rest longer on heavy multi-joint lifts (article 44). Keep most sets one to three reps short of failure (articles 42 and 49). Use the fullest range you control (article 45). A split does not change these rules; it gives them more room.
A real-world example
Consider an illustrative person, not a real case: a 34-year-old office worker who has followed a full-body plan three days a week for about eight months. His squat, row and press are all progressing more slowly, and his sessions now take 80 minutes because he keeps adding sets. His goal is muscle, with strength as a close second. He can reliably train Monday, Tuesday, Thursday and Friday before work, for about an hour.
Applying the APEX filter: Transformation stage, muscle as the primary goal, intermediate in the main lifts, four days available, an hour per session, good recovery. His problem is real: he needs more weekly volume than his full-body sessions can hold. An upper / lower split on those four days (upper Monday, lower Tuesday, upper Thursday, lower Friday) gives him about twice-weekly frequency, room for more sets per muscle, two lower days that are never back to back, and sessions that fit his hour. Here the split solves a problem.
Now consider a different illustrative person: a parent who can train only twice a week, sometimes three, and is six weeks into training. Upper / lower would give each muscle once-a-week frequency on a two-day week and would fall apart whenever a session was missed. Full-body training remains the better fit. Same split, different human, different answer.
What people commonly get wrong
- Choosing it because it sounds more advanced. A split is not a promotion. Moving from full-body to upper / lower is progression only if it moves you closer to your objective.
- Running it on two days and expecting the same result. Two days of upper / lower halves your frequency per muscle compared with two full-body days.
- Overloading the lower days. Heavy squats, heavy deadlifts, lunges and leg press in one session can create far more fatigue than an upper day. Put your heaviest squat-pattern lift and your heaviest hinge-pattern lift on separate lower days rather than both heavy on the same day.
- Letting upper days become push-heavy. Make sure your pulling volume at least matches your pushing volume, as article 28 recommended. Rows, pulldowns and face pulls deserve as many hard sets as presses.
- Forgetting carries, single-leg work and trunk training. They fit naturally on lower days, or as short finishers on either day.
- Back-to-back lower days. Placing lower sessions on consecutive days often leaves the second one under-recovered. Spread them out so at least one day sits between them.
- Changing the plan every few weeks. The split works through repetition. Keep exercises stable long enough to progress them.
Where this fits in APEX
Upper / lower is a structure, not a program family. It can serve several families from the constitution: muscle gain, recomposition and physique within body transformation; general strength and powerlifting preparation within strength; and hybrid programs, where four lifting days can be paired with separate conditioning.
By stage:
- Foundation: usually not needed. Full-body training two or three days a week is simpler and gives more frequent practice of new skills. A Foundation trainee with four reliable days and a strong preference for shorter sessions can use a light upper / lower version, but it is not required.
- Transformation: often a strong choice when four days are available and volume needs are rising.
- Development: very common, because it allows a heavier day and a moderate day for the same patterns within the week.
- Performance: still useful, especially for strength sports and hybrid athletes, though specificity may change what goes into each day.
- Mastery: a durable, easy-to-manage structure for sustaining high capability around a busy life.
Within a training season, the split usually stays the same while the training phases change the dose: lighter, learning-focused work in Learn, rising load and sets in Overload and Amplify, reduced work in Deload, then a check in Reassess. The structure is the frame; the training phases move the dials inside it.
What this means at different levels
Beginner: you rarely need a split. If you choose upper / lower because four short sessions suit your life, keep sessions short, use mostly supported tools you can control, keep two sets per exercise and practise the patterns rather than chasing fatigue.
Intermediate: this is where upper / lower shines. Use A and B days to cover horizontal and vertical pushing and pulling, squat and hinge emphasis, and add volume a set or two at a time when progress stalls and recovery is good.
Advanced: you may run a heavy day and a volume day for each half of the body, with careful fatigue management and planned deloads.
What not to copy
You will see advanced lifters and physique athletes running upper / lower with five or six exercises per muscle group, twenty or more sets per muscle per week, and sessions over 90 minutes. That reflects years of training, high recovery capacity and specific goals. What to take from them is the principle: twice-weekly frequency, stable exercise selection and planned progression. What not to copy is their volume, their exercise count or their session length.
Your next best step
Ask yourself one question: does my current structure stop me doing the weekly volume I need, at about twice a week per muscle, in sessions I can actually finish well?
- If you train two or three days a week and your sessions fit your time, stay with full-body.
- If you can reliably train four days and your full-body sessions have become too long or too tiring to do well, try the four-day upper / lower sample below at your level for one full block of training before judging it.
Keep your logbook, track the main lifts and your session length, and reassess after several weeks. That is how you will know whether the split is serving you.
Next APEX lesson
Article 53 looks at push / pull / legs: another way of dividing the body that becomes useful in different situations, with its own benefits and limits.
