Build Muscle Mass Easy

How to Build Muscle

The biggest muscle building mistake people make is training like a bodybuilder. Many bodybuilders use drugs but won’t tell you. And they rarely built the bulk of their muscle size with the routines they do now. That’s why bodybuilding routines don’t work for most people. This is what works…
1.Get Stronger. The best bodybuilders that ever existed were strong. They knew more strength is more muscle. Increase your Squat to 140kg/300lb, Bench Press to 100kg/220lb, and Deadlift to 180kg/400lb. Your overall muscle mass will increase because strength is size.
2.Add Weight. Forget about pump and soreness. Instead focus on adding weight on the bar. Try to lift more than last time. You’ll get stronger which will increase your overall muscle mass. If you don’t lift more today than last month or year, you’re not building muscle.
3.Do Compounds. Do exercises that work several muscles at the same time. You’ll be able to lift heavier weights which will trigger more muscle growth. The bulk of your routine should consist of heavy Squats, Bench, Deadlifts, Overhead Presses and Barbell Rows.
4.Use Barbells. You can lift heavier weights with barbells than any other tools. You also have to balance the weight yourself. Barbells involve more muscles and trigger more growth. Use free weights not attached to machines. Start light and use proper form to avoid injury.
5.Increase Frequency. The more often you train a muscle, the more you trigger it to grow. The more you do an exercise, the quicker your technique improves, and the heavier you can lift. Start Squatting, pressing and pulling three times a week instead of only once.
6.Recover. Your muscles need to recover from your workouts to grow stronger and bigger. They can’t recover if you work them hard every day. Even your mind needs a break. Take three to four rest days a week. Help your muscles recover by getting plenty of food, water and sleep.
7.Eat More. Your body uses food to fuel workouts, and recover muscles. Your muscles can’t recover and grow if there’s a shortage of food. Most guys need at least 3000kcal/day to build muscle. Skinny guys with high metabolisms need even more to gain weight.
8.Eat Protein. Your body uses protein to build new muscle, and recover damaged muscle tissue post-workout. You need 2.2g protein per kilogram of body-weight (1g/lb) to maximize muscle recovery and build muscle. For an 80kg/175lb guy, that’s about 175g of protein per day.
9.Get Real. You can’t get steroid-like results without using steroids. You can’t turn into Arnold in three months because building muscle takes time. Celebrities set unrealistic expectations. Stop trying to look like them. Focus on improving yourself. It will save you frustration.
10.Be Consistent. Most guys gain 0.25kg/0.5lb of lean muscle per week if they do an effective training program and eat well. You can’t gain muscle faster than this. It takes a year to gain 12kg/24lb of lean muscle and see dramatic change. Consistency is therefore key.

Rate of Muscle Gain

Most guys can gain 0.25kg/0.5lb of lean muscle per week when they start lifting. That’s about 1kg/2lb of muscle per month or 12kg/24lb in a year. This assumes you do an effective training program like StrongLifts 5×5, eat well, and are consistent. Muscle gains slow down after the first year.

Effective Training

Weekly Muscle Gain

Monthly Muscle Gain

Yearly Muscle Gain

1 year 0.25kg / 0.5lb 1kg / 2lb 12kg / 24lb
2 years 0.12kg / 0.25lb 0.5kg / 1lb 6kg / 12lb
3 years too small to track 0.25kg / 0.5lb 3kg / 6lb

Your body-weight can increase by more than 1kg/2lb per month when you start lifting. Your muscles store glycogen to fuel your workouts. Glycogen binds to water which causes water retention and a fuller look. This water weight increases your body-weight. But it’s not pure muscle tissue.

Some guys can gain more than 1kg/2lb of muscle per month. Teens gain muscle faster because they have more testosterone. Skinny kids gain muscle faster because they start under-weight. People who lifted before gain muscle faster thanks to muscle memory. Drugs change everything.

On the other hand, older people gain muscle more slowly because they have less testosterone. Same with females – they usually gain only half the muscle or 12lb the first year. Strong lifters gain muscle more slowly than weak lifters because they already have more muscle mass.

But on average you can expect to gain about 1kg/2lb of muscle per month during your first year on an effective training program. So if you’ve been going to the gym for a while but never did a program like StrongLifts 5×5, you can still gain 12kg/24lb of muscle in the next 12 months.

Most of your muscle gains will happen the first three years. In the beginning you’re weak and have little muscle. So you gain strength and muscle fast – these are the newbie gains. I started out skinny-fat at 60kg/135lb. My weight climbed to 80kg/175lb the first three years, most of it the first year.

But my weight hasn’t changed much since then. The more strength and muscle you have, the harder to gain more. This is the law of diminishing returns – it takes more work to get more, and the return is smaller. Luckily the gains are easier to maintain, and come back faster after a break.

It’s harder to build muscle than to lose fat or get stronger. You can easily lose 0.5kg/1lb of fat per week by eating slightly less. You can easily add 2.5kg/5lb per workout on Squats for weeks with StrongLifts 5×5. But you can’t build more than 0.5kg/1lb of muscle per week. Compare…

Squat Gains

Fat Loss

Muscle Gains

1 Week 7.5kg / 15lb 0.5kg / 1lb 0.25kg / 0.5lb
1 Month 30kg / 60lb 2kg / 4lb 1kg / 2lb
3 Months 90kg / 180lb 6kg / 12lb 3kg / 6lb

This explains why you can’t look like top bodybuilders, fitness models or celebrities in three months. They’ve usually been training for years – Arnold was lifting weights for eight years before winning his first Mr Olympia. And don’t ignore the lightning, tanning, photoshop, drugs, …

You can’t gain more than 1kg/2lb of muscle per month. This is the human genetic limit. The only way to gain muscle faster is by not going slower. It takes a year to gain 12kg/24lb of muscle and make a big change. Be consistent and stay focused so it doesn’t take you two years to get there.

Muscular Potential

How did Ronnie get 65lb bigger than Arnold?
How did Ronnie get 65lb bigger than Arnold?

Your maximum muscular body-weight depends mostly on your height and bone-structure. Tall people can build more muscle mass than short people. People with large, thick frames can gain more muscle than people with narrow builts and small wrists/ankles like me.

Casey Butt Phd has come up with formulas to determine the maximum amount of muscle mass you can gain naturally. His research is based on the muscle size of the world’s top bodybuilders before anabolic steroids existed (source). I’ve turned Casey’s formula in a simple table below.

Height

Maximum Body-weight

Maximum Biceps Size

1m62 / 5'4" 78kg / 172lb 41.5cm / 16.3"
1m67 / 5'6" 82kg / 181lb 42.1cm / 16.6"
1m73 / 5’8” 86kg / 190lb 42.7cm / 16.8"
1m77 / 5’10” 90kg / 199lb 43.4cm / 17.1"
1m83 / 6’0” 94kg / 207lb 44cm / 17.3"
1m87 / 6’2” 98kg / 216lb 44.6cm / 17.6"
1m93 / 6'4" 102kg / 224lb 45.3cm / 17.8"
1m98 / 6'6" 106kg / 233lb 45.9cm / 18.1"

Free: download my muscular potential calculator to discover how much lean muscle you can gain naturally. You’ll get realistic muscle goals based on your height and frame-size. Signup to my daily email tips to get the calculator. Just click here.

These numbers assume a wrist size of 17.8cm/7″, ankle size of 22.9cm/9″ and body-fat of 10%. The biceps size is contracted at the largest point. These numbers are for males only. The female muscular potential is lower since they’re usually shorter, smaller and have less testosterone.

These numbers are based on the achievements of the best bodybuilders that ever existed, including Reg Park. It’s therefore unrealistic to expect gaining as much muscle. These lifters had better work ethics and genetics than the rest otherwise they wouldn’t have become champions.

So be proud if you reach 90% of your muscular potential in lean condition. I’m 5’8″ with 6’7″ wrists. I weigh about 175lb with maybe 12% body-fat. That’s 90% of 190lb. This is why although I’m not a big guy, and may look small on paper, people I meet always notice I lift weights.

These numbers show most guys won’t build a 200lb lean and muscular body. The average height for males in the US is 1m75/5’9″. Unless you’re taller, the only way to get to 200lb is to let your body-fat increase… or take anabolic steroids. Working hard won’t make it happen for natural lifters.

The point isn’t to demotivate you. Quite the opposite – I don’t want you to get demotivated because you set unrealistic goals like 21″ ripped arms. Reg Park had 18.5″ arms, competed at 214lb and was 6’1″ tall. He could Squat 600lb and Bench 500lb. You’re unlikely to do better than him. Really.

It’s true that training and nutrition methods have improved. People gain strength and muscle faster today than in Reg Park’s time. But human genetics haven’t changed – there’s still a limit to how much muscle you can gain naturally. And this still depends mostly on your height and frame size.

What has changed a lot is anabolic steroids. Arnold Schwarzenegger competed at 235lb/6’2″. Three decades later Ronnie Coleman competed at 300lb/5’11”. They both worked hard, both Deadlifted over 700lb, Arnold even admitted using drugs. But one clearly used more to get 65lb bigger…

That’s why natural bodybuilding competitors rarely weigh over 200lb. They can’t get lean enough to show up ripped. Most people compete in the lighter 165lb class because that’s where you end when you drop to single digit body-fat. 200lb ripped, life-time natural physiques are rare.

Muscle Shape

High vs low biceps insertions. Notice the difference in peak.
High vs low biceps insertions. Notice the difference in peak.

Your genetics determine the shape of your muscles. People’s muscles look different for the same reason their faces look different. You can increase the size of your muscles by lifting heavy weights. But you can’t change their shape because you can’t change your genetics. Examples…
•Frame size. People with a short torso like me will have a fuller look than people with a long torso. There’s less muscle mass needed to fill up the same amount of space. People with a long torso will tend to look skinnier and have a smaller waist.
•Muscle insertions. Your biceps will have a bigger peak if you have high biceps insertions. Your calves will look smaller if you have high calf attachments like me because there’s less muscles to work with – most of your lower leg will be bones and tendons.
•Length of limbs. People with long arms and legs like me will tend to look skinnier because there’s more space to fill up. They need to increase their overall muscle size more to make their arms and legs look big. They’ll need to weigh more at the same height by eating more.

Note that you can’t isolate parts of a muscle. You can’t work your lower or outer biceps, or your inner-chest. You’re either working the whole muscle, or you don’t. What you can do is increase the overall size of the muscle so it fills out more. You do that by lifting heavy and eating more.

Role Models

Hugh Jackman, Chris Hemsworth and Daniel Craig have different body-types, and thus look different
Hugh Jackman, Chris Hemsworth and Daniel Craig have different body-types, and thus look different.

Don’t try to look like some celebrity or model. Everyone is built differently as already explained. Your genetics determine the shape of your muscles. So unless you have the same frame size, limb length, and muscle insertions as that celebrity or model, you won’t able to recreate their look.

In fact, movie stars don’t look the same either. Notice in the top picture how Hugh Jackman looks like the biggest of the three. Chris Hemsworth has a longer torso with a smaller lean. Daniel Craig’s torso is shorter and looks more bulky. Their chest and shoulders have different shapes.

Even if you lift and eat the same, you won’t look the same. I trained with my mentor for two years. We did the same sets. reps, and exercises. But I looked different because different genetics. My brothers look different too despite having the same parents. This only works for identical twins.

Most people can’t stick to celebrity workouts anyway. They’re grueling and time-consuming. Actors have time. They get help from personal trainers and cooks. They get motivated by big paychecks. But most hate lifting, quit as soon as filming ends, and get fat. Check Gerard Butler after the 300.

Gerard Butler in Barbados after the 300...
Gerard Butler in the 300, and then in Barbados…

Truth is, most actors don’t look like in the movies the whole year. They only have to look good for a few shirtless shots. And their muscles are accentuated by using special angles, lightning, make-up or even CGI. For the movie posters there’s good-old photoshop. Lots of smoke and mirrors.

And then there’s steroids. Actors are on a tight schedule. They get older but still have to look ripped. Their salary depends for a big part on their looks. Competition is high. This makes steroids tempting. But few are open about using – they don’t want to get problems or disappoint their fans.

The point is that it’s fine to get inspired by celebrity transformations. Chris Pratt goes from fat to fit in six months – cool. Hugh Jackman is still big and strong in his late 40s – great. Just don’t try to get the same results in the same amount of time using the same routine. It won’t work.

More important – don’t try to look like someone else. Build a better body that makes other people want to look like YOU. Do this by increasing your strength and muscle mass first, and then lowering your body-fat to get ripped. This will make you look great regardless of your genes.

Training

Foundation

You can’t build a great building on a weak foundation. And yet many people try to build a great body without doing the basics first. This is why so many of them fail to gain muscle mass. You need to build a strong foundation in order to build a great body. Here’s what that means…
•Foundation of Size. You can’t chisel a marble sculpture without a big block of marble. You can’t pump muscles you haven’t built first. You need to increase your overall muscle mass before you can define it with isolation exercises and cutting diets.
•Foundation of Strength. You can’t get strong and big with high rep isolation exercises – the weights are too light. You need compound exercises to go heavy and get stronger. You can then use that strength to do isolation with heavier weight to sculpt your muscles.
•Foundation of Form. You can’t lift heavy with bad form. Proper form increases lifting safety and efficiency. It increases your strength so you can work your muscles harder with heavier weight. But you have to do the main exercises frequently to master proper form.

It’s tempting to skip this step and go straight after the pump with high rep isolation. But if you build a foundation of size, strength and form first, you will get better results with whatever you decide to do later – whether that is aesthetics, endurance or even more strength.

The challenge is that everything works in the beginning. You can gain muscle by jumping straight into high rep isolation routines. But you won’t build the maximum amount of muscle mass you can build in the shortest amount of time. And you’ll eventually get stuck because you never built a foundation.

This is where many people start to blame their genetics or age. This is where they start buying more supplements. This is where they start considering anabolic steroids. They lack experience to see the issue is their training – they’ve failed to build a strong foundation first.

This muscle building guide is about spending a year on building a foundation of form, strength and size. After that you can specialize if you want. Most people are happy with how they look by training for strength. Some want more aesthetics. But it always starts by building a strong foundation.

Strength Is Size

Arnold Schwarzenegger and Franco Columbo could Deadlift over 700lb
Arnold Schwarzenegger and Franco Columbo could Deadlift over 700lb

More strength is more muscle. If you lift big, you get big. This is why the best bodybuilders that ever existed were strong like bulls. They knew strength equals size.

Here’s how this works: your skeletal muscles are attached to your bones by tendons. Your muscles contract to move your body and lift the weights. The heavier the weight on the bar, the more gravity pulls it down. This forces your muscles to work harder to lift and control the weight.

Lifting heavy weights stresses your body and muscles. It stimulates them to grow stronger and bigger so they can better handle that same stress next workout. This is the stimulus – recovery – adaptation cycle aka what doesn’t kill you make you stronger. Put simply, you lift big, you get big.

Arnold Schwarzenegger agrees. He won the Mr Olympia title seven times. But he also competed in olympic lifting, powerlifting and strongman before becoming a bodybuilder. Arnold could Deadlift 710lb, Bench Press 440lb and Squat 473lb. Here’s what he said about strength…

The truth is that not all bodybuilders are strong, especially those who have done most of their training with weight machines. But years of power lifting and working with free weights had given me massive biceps and shoulders and back muscles and thighs. I simply looked bigger and stronger than the rest.

– Arnold Schwarzenegger, The Education of a Bodybuilder

Arnold wasn’t the first or only bodybuilder that understood strength equals size. There’s a long list of top bodybuilders who can lift big, heavy weights. Here are some examples…
•Franco Columbo. Arnold’s trainingpartner from Sicily. He could Deadlift 755lb, Bench 525lb and Squat 655lb. He even competed as a strongman. Franco won the Mr Olympia twice.
•Reg Park. Arnold’s mentor who probably taught him strength is size. He could Deadlift 700lb, Bench 500lb and Squat 600lb. Reg Park won the Mr Universe title three times.
•Ronnie Coleman. The 8x Mr Olympia champion once said “Everybody wants to be a bodybuilder but nobody wants to lift heavy weights.” He could Deadlift 800lb like peanuts.
•Sergio Oliva. Competed as an Olympic weightlifter nationally. He could lift 300lb overhead and totalled 1000lb. He then switched to bodybuilding and won the Mr Olympia 3x.
•John Grimek. Competed in weightlifting at the Olympic Games. Then switched to bodybuilding and won the Mr America and Mr Universe. Grimek could still Squat 400lb in his 60s.
•Dr Layne Norton Phd. Pro-bodybuilder and powerlifter. Increasing his Squat took his chicken legs from 21″ to 28″ thighs. He Squats 617lb, benches 387lb and Deadlifts 700lb.
•Stan Efferding. Professional bodybuilder who also owns the world record Squat in the 275lb class with 854lb. People often call him the world’s strongest bodybuilder.

These bodybuilders DID high rep isolation routines at one point to chisel their physique. But they were strong first. And they didn’t get strong by doing isolation like curls and flies. They got strong by doing heavy Squats and Deadlifts. This is how they increased their overall size and muscle mass.

Bodybuilders and powerlifters actually used to train the same way. It was normal for them to compete in both. Bodybuilding competitions even used to include feats of strength. Joe Weider changed this in 1946 when he created the IFBB and turned bodybuilding shows into beauty contests.

But strength is still size. That’s why so many strong lifters can pass as bodybuilders if they diet down. Just look at powerlifter Dan Green and olympic weightlifter Dmitry Klokov. Dan Squats 848lb, Dmitry lifts 511lb overhead. Most people couldn’t tell if they do bodybuilding or strength training.

Dan Green and Dmitry Klokov showing that strength is size
Dan Green and Dmitry Klokov showing that strength is size

Now they won’t win bodybuilding competitions against real bodybuilders. But you probably don’t plan to compete. Most guys want to build muscle to get laid (hey, even I did). I don’t know any girl who wouldn’t like a body like that. I don’t know any guy who wouldn’t be happy to look like that.

And sure, they might sneak curls in here and there. But the bulk of their training consists of heavy Squats, presses and pulls because that’s what their sport demands. Their physique is therefore the result of doing a lot heavy lifting. This illustrates the principle of form following function.

Some people think strength training doesn’t build muscle because they’ve seen fat powerlifters. First, they have muscles, big muscles, or they wouldn’t lift big. It’s just hidden behind fat. Powerlifters don’t win by being more ripped than their competitors. They win by lifting heavier weight.

Two, those 300lb pro-bodybuilding mutants are of course more ripped than 300lb powerlifters. The former is strict about his diet, uses all kinds of drugs to get more cut, and is tanned. The latter just eats a ton to maximize muscle recovery and break world records. Different goals.

Here’s how to compare – take a 180lb powerlifter and 180lb natural bodybuilder. Put them side to side without tanning and at similar body-fat levels. The average person wouldn’t be able to tell who the powerlifter is. They’d probably call them both bodybuilders. Heck, they call me a bodybuilder.

Other people think strength training can’t make you big. This contradicts the last point. Plus Andy Bolton Deadlifted 1000lb and weighs over 300lb. I met him, he’s huge. Weight classes in powerlifter go up to 140kg. These guys do tend to be fat. But it’s not all fat because fat doesn’t move weight.

The confusion happens because they’ve seen a light weight powerlifter. In the video below you can see Sergey Fedosienko Squat 300kg at a body-weight of only 58kg. Naive people will conclude he’s not big so lifting heavy weights don’t make you big. This shows a lack of common sense.

Why doesn’t he have more muscle? Why aren’t his arms 18″? Because your maximum muscular body-weight depends mostly on your frame size and height. This guy is only 4.9″. He can’t weigh 100kg without turning fat. 58kg is perfect for his height. But that means no 18″ arms for him. Normal.

Again, powerlifters win by lifting heavier than their competitors. And since there are weight classes, they manipulate their body-weight to end in the category in which they’re most competitive. Small powerlifters often eat strictly to avoid weight gain. They don’t want to end in a heavier category.

But strength is size. Even celebrities have caught on and are now lifting heavy. It’s the most effective way for them to quickly increase their overall muscle mass so they look big on screen. Just look at Hugh Jackman and Henry Cavill Deadlifting heavy for the Wolverine and Superman movies…

Hugh Jackman pulls 461lb and he’s almost 50. He had a point when he wrote on twitter: “if the bar isn’t bending, you’re pretending”. Curls don’t bend bars. Heavy Squats and Deadlifts do. Maybe you don’t care about strength, you just want to build muscle. But lifting heavy is what it takes.

Strength is size doesn’t mean you have to Deadlift 700lb like Arnold. I can’t do that. But get stronger. You’ll see a massive difference by increasing your Squat to 140kg/300lb, Bench to 100kg/220lb, and Deadlift to 180kg/400lb. You can easily do that with StrongLifts 5×5.

And yet most people will make all kinds of excuses to not lift heavy. They’ll do gazillion of exercises and chase pump instead. But this doesn’t work because building size requires gaining strength. You need to lift heavy to increase your overall muscle mass naturally. Get started, today.

Progressive Overload

Milo of croton training for strength and size in ancient Greece
Milo of croton training for strength and size in ancient Greece

In Ancient Greece, Milo of Croton trained for the Olympics by carrying a calf on his back each day. The calf grew bigger which forced Milo to lift heavier weights. Milo’s body became stronger and bigger as a result. He became the strongest guy in his time, winning the Olympics 6x.

It’s a legend. But it illustrates the principle of progressive overload used in effective training programs like StrongLifts 5×5. Gradually increasing the weight stresses your body and muscles. It triggers them to gain in strength and size so they can better handle heavy weights in the future.

Strength is size as already explained. You got to lift big to get big. Progressive overload is how you do it. Start light, add weight each workout, do this as long as you can. Always try to lift more. Because if you’re not lifting heavier weight today than last year or month, you’re not gaining muscle.

It works the opposite way too – Progressive Underload. You’ve seen people getting less active as they age. They use their muscles less by becoming sedentary. They become skinny, weak and fat because what you don’t use, you lose. Your body needs a reason to be strong and muscular.

Besides the fact that progressive overload works, it’s is also the simplest way to progress. The sets, reps and exercises can stay the same. You just add weight. So you know if you’re making progress by looking at the weight on the bar – if it increases over time, you’re gaining muscle.

Most people get addicted to training programs that use progressive overload. They find it motivating to see the weight on the bar increase each workout. They end up looking forward to going to the gym and see how far they can take it. They don’t have to drag themselves as they used to.

Now you can’t add weight forever. Otherwise everyone would be Squatting 700lb. But most people are amazed by how long they can add weight. Of course this is simple but not easy. It’s hard work. Some people don’t have what it takes to push themselves to add weight over and over again…

So many people chase pump instead. They hammer their muscles with high rep failure training. But all this does is bloating up your muscles with water. As soon as you leave the gym, the pump is gone. It’s also hard to pump anything up if you don’t have much muscle mass to start with…

Other people chase soreness. They think being sore after a workout means you’re building muscle. But there’s no link between soreness and muscle growth. Novelty usually causes soreness – a new exercise, weight, rep range, etc. What builds muscle is lifting heavier weights over time.

Some people try to confuse their muscles. They keep changing exercises, sets and reps. This makes it hard to improve your form because you’re never doing an exercise long enough. You also can’t know if you’re making progress because you’re changing too many variables at the same time.

Muscle confusion only ends up confusing you. You gain strength quickly the first weeks you do a new exercise. But this isn’t because you’re building muscle. It’s because your form is improving – you’re getting more efficient. You’re switching exercise before the muscle growth kicks in.

If you want to confuse your muscles, add weight on the bar. This gives your body new stimulus to grow stronger and bigger muscles but without confusing you. Start light to build momentum. Use small jumps of 2.5kg/5lb per workout. Or just do Strong Lifts 5×5 – it uses progressive overload.

Compounds

To build muscle you must do compound exercises that work several muscles at the same time. The bulk of your routine must consist of the big five – Squat, Bench, Deadlift, OHPress and Rows.

Most people try to build muscle with isolation exercises like curls, flies and leg extension. This is ineffective because the weight is too light. Only one muscle group lifts the weight while the rest is taken out of the movement. This limits how heavy you can go. Yet size requires strength.

You can go heavier on the Squat than leg extension because your hips help your legs lift the weight. You can go heavier on the Bench Press than flies because your arms help your chest. You can go heavier with compound exercises because several muscle groups are involved.

The heavier the weight you lift, the bigger the stress on your body, and the bigger the stimulus to grow stronger and bigger muscles. You lift big, you get big. You lift bigger weights with compounds than isolation exercises. That’s why compound exercises are more effective to gain muscle mass.

Put simply…
•Squats > leg extension
•Bench Press > dumbbell flies
•Deadlift > leg curls
•Overhead Press > front raises
•Barbell Row > rear raises
•Chinups > biceps curls
•Dips > triceps kickbacks

Progressive overload is also easier to apply on compound exercises. More muscles are working and the weight is heavier. Adding 2.5kg/5lb to a 50kg/100lb Bench is a 5% jump. But moving from 40lb to 50lb dumbbell flies is a 10% jump. You can add weight longer with compound exercises.

Compound exercises build more muscle symmetry. Since every exercise works several muscles at the same time, you can’t favor the mirror and beach muscles. So you don’t turn into a captain upper-body with big arms but no legs/back. You build a more balance physique instead.

Compound exercises work your body the way you use it in the real world. You never use only one muscle group outside the gym. Your body always moves as one piece. That’s why the strength you build with isolation exercises doesn’t transfer outside the gym. They build fake gym strength.

And since compound exercises work several muscles at the same time, you don’t need to do more than three exercises per workout. This saves time compared to doing isolation exercises where you need double the amount of exercises to work your whole body.

Many people think you need to work a muscle directly for it to grow. If this was true we would have powerlifters with a barrel chest from benching but pencil arms from barely curling. Yet their arms grow bigger because they hold and press the weight when they bench. This triggers growth.

That’s why your triceps doesn’t need much work after benching heavy. One exercise to pump and shape it, maybe. But not five. That can be counter-productive because your arms are small muscles that need recovery to grow. They can’t if you keep hitting them with a ton of isolation.

Much of the confusion comes from seeing bodybuilders doing mostly isolation. But again, many of the top bodybuilders were strong as bulls. They built strength and size by doing mostly compound exercises first. They only did isolation later in their career. Quote from Arnold again…

“Reg Park’s theory was that first you have to build the mass and then chisel it down to get the quality; you work on your body the way a sculptor would work on a piece of clay or wood or steel. You rough it out””the more carefully, the more thoroughly, the better”” then you start to cut and define. You work it down gradually until it’s ready to be rubbed and polished. And that’s when you really know about the foundation. Then all the faults of poor early training stand out as hopeless, almost irreparable flaws. [..]

I was building up, bulking, going after the mass, which to me meant 230 pounds of sheer body weight. At that time, I didn’t care about my waist or anything else that would give me a symmetrical look. I just wanted to build a gigantic 250-pound body by handling a lot of weight and blasting my muscles. My mind was into looking huge, into being awesome and powerful. I saw it working. My muscles began bursting out all over. And I knew I was on my way.”

– Arnold Schwarzenegger, The Education of a Bodybuilder

Let’s say you still think flies will build a bigger chest than Bench Press. If you double your Bench from 110lb to 220lb, you double the strength of your chest, shoulders and arms. So you can now do those flies with more weight than before. That means you get better results from the isolation.

It’s actually fine to do some isolation as long as it’s not the only thing you do. Pareto principle can be a good guideline – 80% compound exercises like Squats, Bench, Deadlift, OHPress and Row. Then 20% isolation like curls to pump and shape muscles. That’s is if you still need to, I don’t bother.