Upper Lower Split (A/B Workout Plan): How It Works and a 4-Day Plan

In short

An upper lower split is an A/B workout plan: workout A trains your upper body and workout B trains your lower body. With four workouts a week, each muscle group is trained about twice; with three, the A/B/A and B/A/B sequence balances out over two weeks. It mainly suits people in their first months of training who have outgrown a full body plan.

The A/B plan is an outstanding plan for building muscle, but it doesn't suit everyone. In this guide I explain everything you need to know about it: the advantages and disadvantages, who it suits, how to plan it and how to progress. Let's start!

What is an A/B (upper lower) split?

In an A/B plan, you divide your body's muscles into two different workouts, workout A and workout B. The most common way is upper body (A) and lower body (B). The plan suits people who train three to four times a week, preferably four.

It mainly suits trainees with a training age of one month up to at most half a year, assuming they also invest in nutrition and recovery. After that it is worth moving on to more advanced plans such as an ABC split or a push/pull/legs split.

This plan is a step up from a full body plan. I recommend moving to an A/B plan after 6 to 8 weeks of full body training. That is the point where you have already used up what the full body plan gives you and no longer see progress in it.

Pros of this split

For beginners, the plan has two main advantages.

Fast muscle gains for beginners

Beginners don't need a very large stimulus to build muscle. When the stimulus is enough to build muscle but not intense, the body also needs a relatively short time to recover from it. As a result, your body makes use of both the stimulus and the recovery, and builds muscle relatively fast.

It is very important to leave at least 3 days between two workouts of the same type (A to A, B to B), so you recover as well as possible.

You practice the technique twice a week

Because you do each workout twice a week, you get to practice your exercises twice a week. For example, if the squat is in workout B, you practice its technique twice a week. That helps you improve your technique significantly, which is very important for beginners.

Cons of this split

Like any plan, this one has downsides. Two are worth knowing about.

Progress on heavy lifts gets harder

Once you reach respectable weights in compound exercises, it gets hard to keep progressing if you do each one twice a week. The body doesn't have enough time to recover, because exercises like the squat, the deadlift and the bench press put a heavy load on your muscles, joints, tendons, ligaments and nervous system.

That is also why I don't recommend a low rep range in this plan. Use the A/B plan to improve your technique, and stick to a medium to high rep range in these exercises. That way you get the improvement in technique, you improve your weights, and you lower the risk of injuries.

Splitting the body into two groups has a catch

Many muscle groups almost always work together. Almost every time you train your chest, your front shoulders and triceps work too. In almost every leg exercise your lower back works too. Your shoulders work in almost every exercise, either directly or to stabilize the weight.

Working with too high a volume may cause injuries, especially in muscles such as the shoulders and the lower back. These are the muscles most sensitive to load, so you need to manage the load that reaches them wisely. I recommend keeping their number of sets to a minimum.

How to schedule the workouts

The order of the workouts should always be A, B or B, A: they alternate.

• Four days a week: for example A on Monday, B on Tuesday, A on Thursday, B on Friday. This keeps workouts of the same type at least 3 days apart (for example Monday and Thursday).
• Three days a week: in week 1 do A, B, A (two A workouts and one B), and in week 2 do B, A, B (one A workout and two B).
• If your week ended with workout A, start the next week with workout B on the same day of the week instead.
• If you miss workout A on its day, do it on your next training day instead of B, so the order stays alternating.

How many sets and reps?

• Aim for about 18 to 26 sets per workout. The goal is about 10 to 20 sets per muscle per week.
• Each workout should take about 60 minutes.
• It is important that at least some of the exercises are compound exercises.

For the shoulders and the lower back, stick to the minimum number of sets, because they work in many other exercises and are sensitive to injuries.

You can combine rep ranges. In the first exercise, focus on a lower rep range, around 8 reps. This helps you build strength. In the other exercises, work in a higher range of 10 to 15 reps. This helps you reach a maximum pump.

If you train fewer than four times a week, you can also work on strength. Use a range of 6 to 8 reps in the first exercise to work on strength. In the second exercise, use 10 to 12 reps to maximize hypertrophy (the process of building muscle).

Which exercises should you do?

For every muscle group, do at least one compound exercise. These exercises work several muscles together.

The second exercise will be an isolation exercise. That way you can emphasize a specific part of the muscle, improve strength in a particular muscle, and maximize the feeling of the pump in the workout.

Isolation exercises also help improve the connection between the brain and the muscles. The mind-muscle connection is the ability to activate the particular muscle you want, consciously and deliberately. For example, in a dumbbell fly, it is the ability to feel your chest and not your shoulders.

In an A/B plan you don't work with a large volume for each muscle, and you can't train every muscle from every possible angle. That is why it is very important to choose your exercises with tweezers (very carefully), so you build muscle as efficiently as possible.

A sample 4-day upper lower plan

Here is a sample plan. It uses the same idea as above, with two differences: for the chest, back and quads the second exercise is another compound exercise from a different angle, and the seated cable row and the Romanian deadlift use 8-10 reps. With this low volume that works well, and you can swap the second exercise for an isolation exercise with 10 to 15 reps if you prefer.

Workout A: upper body

Workout B: lower body

Each workout has 18 sets. If you swap a second exercise, a dumbbell fly or a leg extension are good choices. Here is how the weekly sets add up:

• Four days a week: chest, back, quads and hamstrings get about 12 sets a week each.
• Three days a week (A/B/A, then B/A/B): chest and back get about 12 sets in the first week and 6 in the second; quads and hamstrings get 6, then 12. That averages about 9 sets a week for each of those groups over the two weeks.
• Smaller muscles: your side shoulders, biceps and triceps each get 2 direct sets per upper-body workout, or 4 over a four-day week, plus indirect work in presses and rows. Calves and core get 3 sets per lower-body workout.

For more exercise ideas, see our guides to the best back, chest, leg and glute exercises.

How to progress on this plan

Three things decide how far this plan takes you: adding weight, recovery and food.

Focus on adding weight in your compound exercises

Assuming you are in a bulk, your main aim should be to raise your working weights in compound exercises. Improvement in the bench press, the squat, the pull-up or the deadlift shows progress without a shadow of a doubt.

You probably won't manage to add weight in every set of every workout, and that's fine. You just need to see a trend of improvement. That is why logging your workouts is one of the most important elements of the plan's success.

When you reach the top of the rep range on every set, add a small amount of weight next time.

Get enough rest

Recovery and enough rest are the base of every training plan. If there isn't enough recovery time between workouts, your body won't manage to repair and rebuild the muscle fibers.

Recovery is made up of two main factors: intensity and sleep.

If your workouts are too intense, the stimulus your muscles get will be too big, and you won't manage to recover from one workout to the next. Between two A workouts, and between two B workouts, make sure there is a gap of at least 72 hours (3 days).

Sleep is critical for recovery too. Your body repairs itself while you sleep, so too little sleep means poor recovery. Aim for at least 7 hours of good sleep a night, and if you need more, sleep more.

Eat right

Good nutrition is an essential part of the success of any training plan. If you want to build muscle, eat enough calories, protein, carbohydrates and fat, and make sure your body weight goes up.

If you want to lose fat, you need a cut: you eat fewer calories than your body needs per day, and you lose weight. During a cut, you probably won't manage to raise your working weights much, because your body has less fuel.

Which plan is right for you?

What research says

• Frequency can help, but weekly sets matter most. An earlier, smaller 2016 review (10 studies) found that training a muscle twice a week built more muscle than once a week. A larger 2019 review (25 studies) found that when weekly sets were equal, frequency made little difference. Training more often mainly helps you fit in more weekly sets. With four workouts a week, an upper/lower split trains each muscle twice and reaches about 12 sets.
• About 10 or more sets a week. The 2026 position stand of the American College of Sports Medicine (ACSM) found better muscle growth with 10 or more sets per muscle group per week.
• Sleep at least 7 hours. A joint statement of the American Academy of Sleep Medicine and the Sleep Research Society recommends at least 7 hours of sleep a night for adults aged 18 to 60.

Safety tips

Start every new exercise with a light weight, and add weight only when your technique stays clean. Do a couple of lighter warm-up sets before your first heavy exercise. On the bench press and the squat, use safety arms or a spotter, and lower the weight in a controlled way.

End a set when your technique starts to break down, or if you feel pain or dizziness, and switch to a lighter weight or a pain-free variation. Stop most sets when you could do only one to three more good reps.

Because the shoulders and the lower back work in almost every exercise, keep their direct sets low, as described above. If they feel overloaded, drop a set or two and keep the 3-day gap between two workouts of the same type.

Bottom line

The A/B workout is a strong plan for people who want to build muscle. If you train three to four times a week and you are still fairly new to the gym, it may be excellent for you.

Remember that recovery and nutrition are an essential part of your success. If you stay consistent with a well-planned A/B plan and log every workout, you can make steady progress.

You can use the sample plan in this guide. It is built on the rules above, with the differences noted in the plan: the choice of exercises, sets, reps and rest days, all aimed at building muscle. And if you want to know the basics, read our guide How to Make a Workout Plan.

Frequently asked questions

Is an upper lower split good for beginners?

Yes, after a first period on a full body plan. I recommend moving to an A/B split after 6 to 8 weeks.

Should I train 3 or 4 days a week?

Both work, but I prefer four. Four days give each group two workouts a week; chest, back, quads and hamstrings get about 12 direct sets in the sample plan, while smaller groups get fewer. Three days also works: rotate A, B, A and B, A, B, so each group gets two workouts one week and one the next.

How long should each workout take?

About 60 minutes.

Upper/lower split or push/pull/legs?

An upper/lower split is simpler and fits three or four days. Push/pull/legs suits more experienced people who can train more often.

Where do abs and calves go?

Add them to the lower-body day, as in the sample plan, or split them across both days.

How long should I stay on an A/B plan?

The plan works best for the first months of training, up to about half a year. After that I would move to an ABC or push/pull/legs split.