The Question

There are so many options when trying to create a workout routine for building muscle. But going to the gym 6, 5, sometimes even 4 days per week cannot only be tough on the body, but can become a major inconvenience.

What is the best 3-day split workout? Be descriptive. Include exercises, sets, reps, length of workout, resting intervals, etc.

When doing a 3-day split, should any muscle groups be trained only once per week? Any twice per week? Why?

Who would be interested in doing a 3-day split and how would it help them if they did?

Are there any pros that do a three day split?

Are 3-day splits better for bulking, cutting, maintaining? Why?

Bonus Question: How does a 3-day split match up to a 4-day or 5-day split? Better or worse? Why?

Show off your knowledge to the world!

The Winners

1. ravadongon View Profile

2. BladeMaster View Profile

3. TUnit View Profile

1st Place: ravadongon

With 4-day and 5-day workout splits becoming more and more popular amongst the bodybuilding and fitness community, it seems that 3-day splits are slowly dying away. What many people don't realize is that 3-day splits can be just as effective, if not more so than 4- or 5-day splits, which generally don't allow sufficient time for recovery.

So if you're just starting out, have been experiencing difficulty in choosing a new split or have reached a plateau of late, then you've come to the right place.

Best 3-Day Split

As I always do, I will not include one workout that I feel is THE best for the category, but rather, give you 3 different routines, which are my favorite 3-day splits, that have been proven to yield solid results in both strength and hypertrophy gains. If you like you can complete all 3 routines in 36 weeks (12 weeks/routine).

Warm-Up

Note: Before all your workouts I encourage you perform a proper warm-up to prevent the chances of an injury occurring and also to 'loosen you up' and get you both mentally and physically prepared to perform at your best.

Here is a suggested warm-up; you do not have to follow this but at least make sure you warm-up by first by raising your body temperature slightly (till you break a light sweat) and then performing some dynamic stretching and mobility drills:

Deloading

Note: Make sure you deload at least every 6 weeks. This means decreasing your volume/intensity/frequency for 1 week, so your body has a period in which it can recuperate from hard intense training.

1. Push/Pull/Legs

Legs

• Barbell Front Squats/Barbell Lunges: 4 sets of 4-6 reps
• Romanian Deadlifts/Barbell Good Mornings: 3 sets of  6-10 reps
• Barbell Standing Calf Raises: 3 sets of 6-10 reps
• Weighted Crunches/Weighed Hanging Leg Raises: 3 sets of 8-15 reps

Click Here For A Printable Log Of Push/Pull/Legs.

Push

• Dumbbell Flat Bench Press/Barbell Incline Bench Press: 4 sets of 4-6 reps
• DB Seated Shoulder Press/Barbell Push Press: 3 sets of 6-10 reps
• Barbell Lying Tricep Extensions or Barbell Close-Grip Bench Press: 3 sets of 6-10 reps

Click Here For A Printable Log Of Push.

Pull

• Deadlifts/Snatch Grip Deadlifts: 4 sets of 4-6 reps
• Pull-ups/Cable Rows: 3 sets of 6-10 reps
• Dumbbell Seated Bicep Curls/Barbell Preacher Curls: 3 sets of 8-12 reps

Click Here For A Printable Log Of Pull.

Suggested Schedule

• Mon: Legs
• Tue: GPP/HIIT Cardio/Off
• Wed: Push
• Thu: GPP/HIIT Cardio/Off
• Fri: Pull
• Sat: GPP/HIIT Cardio/Off
• Sun: REST/Recovery

Comments

This workout has been designed for beginners. Your experience level does not matter when using this template, and even more advanced trainers who have been training high volume for an extended period of time, may find this switch to low volume training beneficial.

Work on training heavy for the first exercise for each workout, go to failure and attempt to increase weight from the previous session, or at least repetitions. Make sure you warm-up properly for the exercise (progress to heavier weights). Get at least 3-4 minutes rest between work sets (less needed for warm-up sets).

For the other exercises do not work till complete failure, stop at least 1-2 reps short. Work on gradually increasing repetitions each session and eventually load, once you have reached the end of the allotted range. Get at least 2 minutes rest between these work sets.

Rotate exercises every 3 weeks.

2. Upper/Lower

Upper

• Weighted Dips/Barbell Incline Bench Press: 5 sets of 3-6 reps
• Bent Over Rows/Weighted Chin-ups: 3 sets of 6-8 reps
• Barbell Close-Grip Bench Press/Barbell Skull-crushers: 3 sets of 8-12 reps
• Dumbbell/Barbell Curls: 3 sets of 8-12 reps
• Weighted Crunches/Weighed Hanging Leg Raises: 3 sets of 8-12 reps

Click Here For A Printable Log Of Upper.

Lower

• Barbell Low Box Squats/Sumo Deadlifts: 5 sets of 3-6 reps
• Dumbbell Split Squats/Dumbbell Lunges: 3 sets of 8-15 reps
• Reverse Hyper Extensions/Good Mornings: 3 sets of 8-15 reps
• Cable Woodchoppers/Side Bends: 3 sets of 8-12 reps

Click Here For A Printable Log Of Lower.

Suggested Schedule

Week 1

• Mon: Upper
• Tue: GPP/HIIT Cardio/Off
• Wed: Lower
• Thu: GPP/HIIT Cardio/Off
• Fri: Upper
• Sat: GPP/HIIT Cardio/Off
• Sun: REST/Recovery

Week 2

• Mon: Lower
• Tue: GPP/HIIT Cardio/Off
• Wed: Upper
• Thu: GPP/HIIT Cardio/Off
• Fri: Lower
• Sat: GPP/HIIT Cardio/Off
• Sun: REST/Recovery

Repeat...

Comments

This template is designed for intermediate trainers, with around 4 months or more worth of solid training experience.

Work on training heavy for the first exercise for each workout, go to failure and attempt to increase weight from the previous session, or at least repetitions. Make sure you warm-up properly for the exercise (progress to heavier weights). Get at least 3-4 minutes rest between work sets (less needed for warm-up sets).

For the other exercises do not work till complete failure, stop at least 1-2 reps short. Work on gradually increasing repetitions each session and eventually load, once you have reached the end of the allotted range. Get at least 2 minutes rest between these work sets.

Rotate exercises every other session.

3. Full-Body

Full-Body A

• Flat Barbell Bench Press/Barbell Floor Press: 5 sets of 3-6 reps
• Dumbbell Split Squats/Barbell Lunges: 3 sets of 8-15 reps
• Cable/Horizontal Rows: 3 sets of 8-12 reps
• Good Mornings/Hyperextensions: 3 sets of 8-12 reps

Click Here For A Printable Log Of Full-Body A.

Full-Body B

• Barbell Back Squats/Deadlifts: 5 sets of 3-6 reps
• Barbell/Dumbbell Military Press: 3 sets of 8-12 reps
• Cable Pull throughs/Reverse Hyper Extensions: 3 sets of 8-12 reps
• (Weighted) Pull-ups/Lat Pulldowns: 3 sets of 8-12 reps

Click Here For A Printable Log Of Full-Body B.

Full-Body C

• Barbell/Dumbbell Bent-Over Rows: 5 sets of 4-6 reps
• Barbell Front Squats: 3 sets of 8-15 reps
• Barbell/Dumbbell Incline Bench Press: 3 sets of 8-12 reps
• Barbell Stiff-Legged Deadlifts/Dumbbell Romanian Deadlift: 3 sets of 8-15 reps

Click Here For A Printable Log Of Full-Body C.

Suggested Schedule

• Mon: Full body A
• Tue: GPP/HIIT Cardio/Off
• Wed: Full body B
• Thu: GPP/HIIT Cardio/Off
• Fri: Full body C
• Sat: GPP/HIIT Cardio/Off
• Sun: REST/Recovery

Comments

This workout is not designed for beginners. Make sure you have at least 6 months worth of solid training experience before you try a high frequency split like this.

Work on training heavy for the first exercise for each workout, go to failure and attempt to increase weight from the previous session or at least repetitions. Make sure you warm-up properly for the exercise (progress to heavier weights). Get at least 3-4 minutes rest between work sets (less needed for warm-up sets).

For the other exercises do not work till complete failure, stop at least 1-2 reps short. Work on gradually increasing repetitions each session and eventually load, once you have reached the end of the allotted range. Get at least 2 minutes rest between these work sets.

Rotate exercises every 2-3 weeks.

Muscle Groups

This depends on how long you've been training and your recovery abilities, which tie in with that. If you are beginning or with little experience (less than 2 years worth of training), then training each muscle group once a week is sufficient for a 3-day split, and anymore will be pushing the boundaries of overtraining.

As you become more experienced and your recovery abilities improve you can start looking at increasing frequency and possibly putting extra time into working on weaker areas of your physique, so they can be brought up.

Who Will Benefit?

Anyone can do a 3-day split, regardless of you experience and training goals.

Beginners can start of with low volume splits to learn the ropes and build up a solid base. Intermediate trainers can start to step up the volume a little (or keep it low volume), as well as the intensity, as their recovery abilities start to improve. Advanced trainers can use high volume 3-day splits, or increase frequency, by incorporating full-body workouts.

Bodybuilders, powerlifters and athletes can all use 3-days splits. Although these trainers all have slightly different goals with their weight training splits, they can all follow a structure based on weight training 3-days per week, because of its versatility, adaptability and recovery time.

Also a 3-day split is ideal for busy people, who find themselves always on the go, with little time to make it to the gym. 3-day splits make it easier for such people to find time in their busy lives to workout and keep strong and fit.

Pros: Are there any pros that do a 3-day split?

You'll find that most IFBB professionals will not use 3-day splits, because of their massive supplement arsenal, that allows them to enhance their recovery abilities by copious amounts compared to the average trainer. So these guys will tend to use much higher frequency templates (>5 days per week), due to the fact the more you stimulate a muscle to grow, the greater opportunity it has to grow (providing the CNS is fully recovered each workout and you are training hard and smart).

However, a lot of WNBF professionals, and amateur bodybuilders and powerlifters, as well as a lot of professional athletes in other sports such as football, wrestling, track and field, boxing, Aussie Rules Football and rugby, use 3-day per week weight training routines.

Are 3-day splits better for bulking, cutting, maintaining? Why?

These goals are almost entirely dependent on your diet, not on your lifting routine. For bulking a calorie surplus is required, for cutting a calorie deficit is needed and for maintaining your current weight, calorie equilibrium should be aimed for.

However some lifters find that muscle group splits allow them to lift greater loads, because specific and general fatigue will be less inclined to occur, as say, in upper/lower of full body workouts. So people who follow this train of thought will tend to choose those types of splits, whether they be 3, 4 or 5 days, for their bulking cycles.

Some lifters also believe that full body splits should be used for cutting because of the fact full-body splits (which can be performed 2-or-3 days per week) burn much calories per workout, as more muscle groups are being drawn upon each session.

In my opinion, it really doesn't matter what type of format you use for bulking/cutting/maintaining, as long as the format you are using advocates progressive overload, mainly by encouraging progressively heavier weights to be used, and does not promote overtraining, then I am all for it. As I said before, three day splits are versatile and because of this can be used whatever you goals are.

Bonus: How does a 3-day split match up to a 4-day or 5-day split? Better or worse? Why?

In my opinion 3-day splits are in general the best option for the natural trainer.

Firstly, 3-day splits also allow for a lot of variety. You can use a wide range of different combinations of muscle groups, movements and the like, to construct your own 3-day split. You can do muscle group splits like the famous push/pull/legs, or if you feel inclined to increase the frequency more then a three day upper/lower template or full body split can be arranged.

It doesn't matter whether you're training goals are, whether they are primarily based around strength or hypertrophy gains or combination of the two, three days splits can be used by anyone, whether you're experienced or not.

Secondly, 3-day splits are convenient. Not everyone has time to go to the gym, four or five days per week, but only having to go three days per week, makes the equation much easier for busy people to still get the fitness results they desire.

Thirdly and finally, you are less likely to be overtraining with a 3-day split, while still getting intense workouts when you do train. With at least 1 day of recovery or rest between each workout, your CNS gets a break from high intensity training, and you can come back the next day, fresh and ready for another intense workout.

Best of luck with your goals,

Ravadongon

2nd Place: BladeMaster

Best 3-Day Split

The best 3-day split workout is one that will work all the muscle groups in your body and give them enough time to rest and grow. This workout is best if you have limited time like most people, and have a desire to gain mass and strength in a few short weeks.

The most important thing to remember is to not give up and to keep working out, do not miss a day because this will mess up your whole schedule. It is vital that you do your 3 days a week or you will not have enough rest and you will not grow.

The workout will be split into 3 different body groups, each designed to allow for adequate amount of rest and also made to be completed in a short amount of time. Workout should take no longer than 1 hour, but should be a minimum of 45 minutes. If you have a partner, rest when your partner is doing their set and vice versa.

Day 1: Chest, Triceps, Delts

• 2 x 10 Bench press
• 2 x 10 Close-grip bench press
• 2 x 10 Incline bench press
• 2 x 8 Dumbbell flyes
• 2 x 8 Skull crushers
• 2 x 10 Tricep extensions
• 2 x 15 Front dumbbell raise
• 2 x 15 Side dumbbell raise

Click Here For A Printable Log Of Day 1.

Your triceps should be fully pumped; delts and chest should be solid as a rock after this workout.

Day 2: Rest

You deserve this day off, make sure to eat right and rest. If you're sore from the day before, massage and stretch those sore muscles. If you're not sore, then think about using heavier weight next time.

Day 3: Biceps, Back, Traps, Forearms

• 3 x 10 Barbell curls (try wide and close grips too)
• 2 x 10 Concentration curls
• 2 sets of pullups to failure (if you can do them)
• 2 x 10 Lat pulls
• 2 x 10 Bent-over Rows
• 3 x 10 Wrist curls
• 2 x 10 Barbell shrugs
• 2 x 10 Calf raise machine shrugs

Click Here For A Printable Log Of Day 3.

Day 4: Rest

If you did everything right this week, you should be sore from yesterday's workout. If not, you know what to do—lift heavier! Be safe when lifting though, you don't want to get injured.

Day 5: Quads, Glutes, Hamstrings and Calves

• 3 x 10 Squats
• 2 x 10 Barbell deadlifts
• 3 x 10 Leg press
• 2 x 10 Leg extensions
• 3 x 10 Calf raises
• 2 x 10 Barbell lunges
• 2 sets Farmer's walk

Click Here For A Printable Log Of Day 5.

This should be your favorite day because this is when you pack on mass from those squats that work those large leg muscles and release growth hormone throughout your body. Your base also gets stronger and you will be able to lift more next week! Have a cheat meal the next day as a reward for going through this punishing and painful week.

Days 6 and 7: Rest

Muscle Groups

Because the legs are a big muscle group, you should only work them out once a week. Compared to other the muscle groups, they take the longest to recover because they contain the most muscle fibers and can result in higher levels of soreness.

Some muscles that can be trained more than once a week would include the forearms, traps and delts. This is because these muscles are small and are used to being used frequently, therefore they have high endurance.

The only way to get them to grow when they have high endurance is to work them constantly and with heavy reps. Working them more than 3 times per week is pushing it though, so do not over train and keep working them out about 1-2 times a week.

Who would be interested in doing a 3-day split and how would it help them if they did?

A 3-day split body workout can be beneficial to anyone, from the beginner to the more advanced bodybuilder. If you are a beginner it can help by getting the body ready to take the overload of future lifting by working the whole body with heavy weights.

Also, remember that the beginner does not know much about the anatomy of the body and what muscles to specifically workout each day because it is known that certain muscles are used in conjunction with others in some exercises, such as bench press which utilizes the pectoral and triceps muscles, consequently making the chest and triceps one big muscle group.

The beginner may not know this, so this workout will make sure that they work muscles by group and not by location or preference. A person new to weight lifting may also not have the time to have a workout every day, so this 3-day-per-week workout is great for those short on time.

Finally and most importantly, it will teach the beginner to be consistent with their workout and have strict discipline, something that will help them greatly in their weightlifting life.

For the advanced bodybuilder, it is important to change workouts every couple of weeks. This is because after a while, the human body adapts to change, such as a 5-day workout. This workout is the perfect way to keep the body from getting used to a certain workout and plateauing.

Sometimes bodybuilders tend to workout for size or strength; this workout will help both and not just one. This can prove to be advantageous to the advanced bodybuilder as it can help gain mass or strength by taking more time off to rest.

Pros: Are there any pros that do a 3-day split?

Not many pros out there use the 3-day split for one reason. That's because they do longer split workouts (5-6 days long), instead of 3. They are able to do this because this is their job and they have all the supplements to help them recover faster, letting them workout longer than the average Joe.

There are a couple of amateur bodybuilders out there that use the 3-day split workout routine such as Russ Hosmer. Russ Hosmer uses a combination of 3-and-4-day splits, and depending on his needs he changes it around a bit.

Are 3-day splits better for bulking, cutting, maintaining? Why?

3-day splits are better for bulking because it can quickly add mass with a strict workout and a proper diet. One reason why it would not be good for cutting is because in cutting you are shedding fat, normally by doing cardiovascular exercises.

As you will be working out your legs heavily, you will not be able to do most cardio exercises such as running, treadmill or jump rope without refusing your legs of their much-needed rest.

3-days splits are too heavy to be used to maintain muscle or tone, because they overload the muscle and instead of toning or increasing endurance, they will add size and strength. Higher reps and sets are what increases endurance, so this workout will not significantly increase endurance, making maintenance hard with this workout.

Bonus: How does a 3-day split match up to a 4-day or 5-day split? Better or worse? Why?

As mentioned earlier, professional bodybuilders use more days in their split workouts because it allows them to do more in less time. They have supplements that help them recover their bodies much faster, therefore they can come back and work a muscle group more than once a week without overtraining.

But, we are not all pro bodybuilders, so we have to use shorter days to achieve our goals. One way to do that is to use the 3-day split workout which will workout the whole body in the least amount of time. 4-or-5-day splits will only increase the risk of overtraining and injury.

If you want to grow quickly but safely, use the 3-day split as it will give you enough rest. The key is consistency because you do not want to miss a day that will impair your ability to recover and grow.

3rd Place: TUnit

Best 3-Day Split

When making a 3-day split workout, you want to stick to compound movements and keep it simple while hitting all the major muscle groups. Periodization is key for reaching one's goals for hypertrophy.

Here is a sample 10 Week, three days per week split in which each workout should be done in well under an hour:

Weeks 1-4 (Loading)

Rest Intervals: 1 Minute

Monday:

• Full Squats: 4 Sets of 8-12 Reps
• Romanian Deadlifts: 4 Sets of 8-12 Reps
• Bench Press: 4 Sets of 8-12 Reps
• Pendlay Bent-Over Rows: 4 Sets of 8-12 Reps
• Superset: Dumbbell Curls/Skull Crushers: 3 Sets of 8-12 Reps
• Abdominal Superset (Russian Twists, Twisting Sit-Ups): 3-4 Sets of 8-12 Reps

Click Here For A Printable Log Of Weeks 1-4 Monday.

Wednesday:

• Military Press: 4 Sets of 8-12 Reps
• Pull-Ups: 4 Sets of 8-12 Reps
• Dips: 4 Sets of 8-12 Reps
• Bent-Over Rows: 4 Sets of 8-12 Reps
• Superset: Barbell Shrugs/Lateral Raises: 4 Sets of 8-12 Reps
• Calf Raises: 3-4 Sets of 8-12 Reps

Click Here For A Printable Log Of Weeks 1-4 Wednesday.

Friday:

• Split Squats: 4 Sets of 8-12 Reps
• Snatch-Grip Deadlifts: 4 Sets of 8-12 Reps
• Incline Bench Press: 4 Sets of 8-12 Reps
• Chin-Ups or Pendlay Bent-Over Rows: 4 Sets of 8-12 Reps
• Superset: Reverse Curls/Skull Crushers: 3 Sets of 8-12 Reps
• Abdominal Superset (Weighted Sit-Ups, Leg Raises): 3-4 Sets of 8-12 Reps

Click Here For A Printable Log Of Weeks 1-4 Friday.

Week 5 (Deloading)

Rest Intervals: 2 Minutes.

Monday:

• Full Squats: 2 Sets of 8-12 Reps
• Romanian Deadlifts: 2 Sets of 8-12 Reps
• Bench Press: 2 Sets of 8-12 Reps
• Pendlay Bent-Over Rows: 2 Sets of 8-12 Reps
• Superset: Dumbbell Curls/Skull Crushers: 2 Sets of 8-12 Reps
• Abdominal Superset (Russian Twists, Twisting Sit-Ups): 3 Sets of 8-12 Reps

Click Here For A Printable Log Of Week 5 Monday.

Wednesday:

• Military Press: 2 Sets of 8-12 Reps
• Pull-ups: 2 Sets of 8-12 Reps
• Dips: 2 Sets of 8-12 Reps
• Bent-Over Rows: 4 Sets of 8-12 Reps
• Superset: Barbell Shrugs/Lateral Raises: 2 Sets of 8-12 Reps
• Calf Raises: 2 Sets of 8-12 Reps

Click Here For A Printable Log Of Week 5 Wednesdays.

Friday:

• Split Squats: 2 Sets of 8-12 Reps
• Snatch-Grip Deadlifts: 2 Sets of 8-12 Reps
• Incline Bench Press: 2 Sets of 8-12 Reps
• Chin-Ups or Pendlay Bent Over Rows: 2 Sets of 8-12 Reps
• Superset: Reverse Curls/Skull Crushers: 2 Sets of 8-12 Reps
• Abdominal Superset (Weighted Sit-Ups, Leg Raises): 3 Sets of 8-12 Reps

Click Here For A Printable Log Of Week 5 Friday.

Weeks 6-9 (Heavy Loading)

Rest Intervals: 1 Minute.

Monday:

• Full Squats: 5 Sets of 6-8 Reps
• Romanian Deadlifts: 5 Sets of 6-8 Reps
• Superset: Bench Press/Pendlay Bent Over Rows: 5 Sets of 6-8 Reps
• Superset: Dumbbell Curls/Skull Crushers: 4 Sets of 6-8 Reps
• Abdominal Superset (Russian Twists, Twisting Sit-Ups): 4 Sets of 8-10 Reps

Click Here For A Printable Log Of Weeks 6-9 Monday.

• Superset: Military Press/Pull-Ups: 5 Sets of 6-8 Reps
• Superset: Dips/Bent Over Rows: 5 Sets of 6-8 Reps
• Superset: Barbell Shrugs/Lateral Raises: 5 Sets of 6-8 Reps
• Calf Raises: 4 Sets of 6-8 Reps

Click Here For A Printable Log Of Weeks 6-9 Wednesday.

Friday:

• Split Squats: 5 Sets of 6-8 Reps
• Snatch-Grip Deadlifts: 5 Sets of 6-8 Reps
• Superset: Incline Bench Press/Chin-Ups or Pendlay Bent-Over Rows: 5 Sets of 6-8 Reps
• Superset: Reverse Curls/Skull Crushers: 4 Sets of 6-8 Reps
• Abdominal Superset (Weighted Sit-Ups, Leg Raises): 4 Sets of 8-10 Reps

Click Here For A Printable Log Of Weeks 6-9 Friday.

Week 10 (Deloading)

Rest Intervals: 1 Minute.

Monday:

• Full Squats: 2 Sets of 8-12 Reps
• Romanian Deadlifts: 2 Sets of 8-12 Reps
• Bench Press: 2 Sets of 8-12 Reps
• Pendlay Bent-Over Rows: 2 Sets of 8-12 Reps
• Superset: Dumbbell Curls/Skull Crushers: 2 Sets of 8-12 Reps
• Abdominal Superset (Russian Twists, Twisting Sit-Ups): 3 Sets of 8-12 Reps

Click Here For A Printable Log Of Week 10 Monday.

Wednesday:

• Military Press: 2 Sets of 8-12 Reps
• Pull-Ups: 2 Sets of 8-12 Reps
• Dips: 2 Sets of 8-12 Reps
• Bent-Over Rows: 4 Sets of 8-12 Reps
• Superset: Barbell Shrugs/Lateral Raises: 2 Sets of 8-12 Reps
• Calf Raises: 2 Sets of 8-12 Reps

Click Here For A Printable Log Of Week 10 Wednesday.

Friday:

• Split Squats: 2 Sets of 8-12 Reps
• Snatch-Grip Deadlifts: 2 Sets of 8-12 Reps
• Incline Bench Press: 2 Sets of 8-12 Reps
• Chin-Ups or Pendlay Bent-Over Rows: 2 Sets of 8-12 Reps
• Superset: Reverse Curls/Skull Crushers: 2 Sets of 8-12 Reps
• Abdominal Superset (Weighted Sit-Ups, Leg Raises): 3 Sets of 8-12 Reps

Click Here For A Printable Log Of Week 10 Friday.

Muscle Groups

When doing a 3-day split, should any muscle groups be trained only once per week? Any twice per week? Why?

In a 3-day split, the calves should be trained directly only once per week. If one does running or plays a sport, the calves are worked heavily in those activities. Calves are also synergists in squats and deadlifts. The shoulders and traps are trained directly 1x per week but again, they are synergists in Bench Press (Shoulders) and Deadlifts (Traps). All of the other muscle groups are trained directly 2x per week.

Who?

Who would be interested in doing a 3-day split and how would it help them if they did?

I think that anyone interested in bodybuilding or athletics should consider a 3-day split. This is because too many people do 5 or 6 days-per-week splits and are under the impression that more time in the gym leads to more muscle growth but this is completely false.

The often forgotten variable in muscle growth is REST and with a 3-day split, one is able to get plenty of it which is why in my opinion it is one of the best splits for hypertrophy. Also your body functions as a whole and not as separate body parts so training it as a whole is important. 3-day splits also are user friendly in that you train 3x per week which can help people out if they have busy or hectic schedules.

Pros: Are there any pros that do a three day split?

Only one that I know of: Dave Goodin - All Natural Mr. Universe

Are 3-day splits better for bulking, cutting, maintaining? Why?

3-day splits are probably better for bulking and maintaining. But the most important aspect of bulking, cutting or maintaining is one's diet. You can have the best training program in the world but if your diet is not up to par then you will not make gains.

One's diet will ultimately decide whether they will bulk, cut or maintain. In order to bulk on a 3-day split, you need to have a caloric excess of at least 500 calories per day which would translate to 1 pound gained per week.

If you want to maintain, there should be no caloric excess or deficit. If you want to cut, there should be a caloric deficit of about 500 calories per day, but usually not more. When you cut, you don't want to lose muscle, you want to lose fat and typically losing more than 1 lb per week ends up in some lost muscle.

Bonus: How does a 3-day split match up to a 4-day or 5-day split? Better or worse? Why?

Personally, I use a 3-day split for every purpose - strength, hypertrophy, etc. 4-day and 5-day splits can be effective but again, the effect of rest is much greater in a 3-day split and outweighs some of the benefits of other splits. So in my opinion a 3-day split > 4-day split > 5-day split.