A Complete Guide to Natural Muscle Building Potential and Arm Size
This Guide Teaches You:
About the genetics of top natural bodybuilders, past and present.
How training and nutritional advancements have not yielded larger natural physiques.
What research has to say about natural bodybuilding limits.
The natural bodybuilding standards of several major industry experts.
How much muscle mass you can expect to gain each year.
The factors that limit how big a muscle can get naturally.
How big you can expect your arms to get naturally.
If somatotyping is something you should be concerned about.
Table of Contents:
1. Genetics of the Greatest Natural Bodybuilders in History
1.1. Comparing Modern & Classic Bodybuilders
2. Digging Deeper: The Case For Physiological Bodybuilding Limits
2.1. Dr. Casey Butt's Research
2.2. Lyle McDonald Natural Muscle Building Model
2.3. Marc Perry Lean Body Mass Formula
2.4. Martin Berkham/Lean Gains Lean Body Mass Formula
2.5. Alan Aragon Model
2.6. Dr. Casey Butt's Yearly Standards
3. A Meta-Analysis of the Natural Bodybuilding Expectation Formulas and Methods
4. Factors That Limit Natural Muscle Building
4.1. Natural Testosterone & Human Growth Hormone Levels
4.2. Nitrogen Retention
4.3. Natural Myostatin Levels
5. Opposing Viewpoints and Arguments
6. Supporting Viewpoints and Arguments
7. A Look At Current Natural Bodybuilding Champions & Pros
8. Natural Arm Size Potential
8.1. Calculate Potential Arm Size - Wrist Method
8.2. Arm Size And Big Lies
8.3. The Reality of Diminishing Arm Size Progress
9. The Reality of Somatotyping
9.1. Moving Beyond Body Types
Natural muscle building potential is one of the most controversial topics in the lifting industry. When you try to assist natural lifters by providing them with reasonable expectations it's a case of you're damned if you do, damned if you don't.
Discussions on how much muscle you can build, or how large you can expect your arms to be, are typically met with an abundance of vitriolic responses. A large portion of the natural bodybuilding realm isn't interested in hearing the truth. They consider it to be too restrictive.
We live in an age where people do not want to be limited. Mantras such as if I can dream it I can achieve it permeate our culture, and have become interwoven into the fabric of modern existence. If you challenge this belief by explaining physiology reality, you are met with comments that go something like this:
"I believe I can keep getting bigger. All I need to do is keep trying harder."
"No one will limit me! Talk of expectations only sets the bar too low. It limits progress instead of encouraging it!"
This article is going to present you with a neutral look at the science of natural genetic potential. Please understand that before we move forward, I encourage you to look at natural expectations as goals, not restrictions. The reality is that few natural lifters ever reach these standards. Therefore, they are presented to set the bar high, not low.
I will start by taking a look at the greatest natural bodybuilders of all-time.
Genetics of the Greatest Natural Bodybuilders in History
The Classic Bodybuilders
Steve Reeves. Steve Reeves was Mr. Universe in 1950. He is best known for his pursuit of symmetry and aesthetics. Steve developed arguably one of the best natural physiques in the history of the sport. He also prided himself on his levels of flexibility and cardiovascular fitness.
Peak stats for Steve Reeves:
Height - 6'1"
Weight - 214 pounds
Body Fat % - Approx. 9%
Arm Size - 18"
Leg Size - 25.5"
Chest - 49.5"
Lean Body Mass - 194.7 pounds
John Grimek. John Grimek won the 1940 & 1941 Mr. America contests. He continued to compete in the sport until 1949. John was known for his impressive muscle size and density, as well as his impressive strength.
Peak states for John Grimek:
Height - 5'8.5"
Weight - 208 pounds
Body Fat % - Approx. 11.3%
Arm Size - 18"
Leg Size - 25.7"
Chest - 49.9"
Lean Body Mass - 184.5 pounds
George Eiferman. George Eiferman won the 1948 Mr. America contest. 14 years later, in 1962, he took home the Mr. Universe title.
Peak stats for George Eiferman:
Height - 5'7.5"
Weight - 195 pounds
Body Fat % - Approx. 10.5%
Arm Size - 16.7"
Leg Size - 25.0"
Chest - 47.5"
Lean Body Mass - 174.5 pounds
Looking at the stats of these 3 legendary naturals, several important points stand out. The first thing we notice is that even with slightly higher body fat percentages than modern natural bodybuilders, these champions could not push beyond the 18 inch arm barrier. The second thing we notice is that 25 inch quads were a championship-level norm.
Finally, it's interesting to note that the base lean body masses of these competitors are comparable to modern bodybuilders. Times may have changed, but natural champions are not getting any bigger. They are getting leaner though.
Let's take a look at several modern natural champions.
Modern Champion Bodybuilders
Now it's time to move into the modern era. The following three natural bodybuilders are all top notch competitors, and run at a similar height compared to the classic era champions featured above.
Brad Borland. Brad Borland is a lifetime natural bodybuilder who has competed 10 times.
Peak states for Brad Borland:
Height - 6'2"
Weight - 215 pounds
Body Fat % - Approx. 8%
Arm Size - 18"
Leg Size - Unknown
Chest - 48"
Lean Body Mass - 197.8 pounds
Ty Dinh. Ty Dinh took home the 2012 Natural Mr. Minnesota competition. He is an IFPA pro bodybuilder who has been competing for over 10 years.
Peak states for Ty Dinh:
Height - 5'9"
Contest Weight - 166 pounds
Off-Season Weight - 195 pounds
Contest Body Fat % - Approx. 6%
Off-Season Body Fat % - Approx. 10%
Arm Size - 17.5"
Leg Size - 27.5"
Chest - Unknown
Contest Lean Body Mass - 156 pounds
Off-Season Lean Body Mass - 175.5 pounds
Stu Yellin. Stu Yellin is a 2-time natural pro bodybuilder, holding pro cards in both the WNBF and the USBF.
Peak states for Stu Yellin:
Height - 5'8"
Contest Weight - 178 pounds
Contest Body Fat % - Approx. 6%
Arm Size - 17"
Leg Size - Unknown
Chest - Unknown
Contest Lean Body Mass - 167.3 pounds
Comparing Modern & Classic Bodybuilders
Let's start by comparing the tallest lifters of the group: Steve Reeves and Brad Borland. Brad is an inch taller, slightly leaner, but weighs about the same as Steve. Both men have 18 inch arms, while Steve Reeves has a slightly larger chest. Brad Borland carries about 3 more pounds of lean body mass, but considering he is an inch taller, puts him on par with Steve Reeves.
Moving on down the list, we have John Grimek and Ty Dinh. Ty is a half inch taller, but carries a lower lean body mass than Grimek. Because of this body mass difference, John also has a slight arm size advantage. Ty Dinh is much leaner in contest shape, but appears to sacrifice some lean body mass to achieve this level of conditioning.
Finally we have the shortest lifters in the group: George Eiferman and Stu Yellin. Stu has a slight height advantage, but like his other modern counterparts features a leaner physique. George Eiferman carries around more lean body mass, but this is likely a product of the competition standards from his era. George did not have to be ultra shredded to win.
So what can we learn from these comparisons? Despite any proclaimed advancements in training, nutrition and supplementation science over the last 60 years, modern lifters do not carry around any more muscle mass or arm size.
Modern bodybuilders tend to be leaner, but that is more a result of changing competition standards. "Shredded" helps win contests, not simply sheer muscle size.
Classic bodybuilders also appear to have smaller legs. This is likely due to a shift in focus, with modern bodybuilding placing a great emphasis on lower body training. When looking at lean body mass numbers, this size advantage does not create an overall lean body mass advantage for modern bodybuilders.
The Bottom Line
60 years hasn't changed much. Ignoring slight statistically unimportant variances, modern lifters are not bigger. Arm size hasn't changed either.
We hear a lot about modern advancements, and there is a much greater emphasis placed upon science in modern bodybuilding, but despite these perceived advancements a physiological reality emerges: natural bodybuilders are no bigger now than they were 60 years ago.
But to be fair, this analysis is statistically insignificant. While it hints at truth, we must take a more detailed and scientific look at natural muscle building expectations.
Digging Deeper: The Case For Physiological Bodybuilding Limits
Dr. Casey Butt's Research
Let's begin by looking at the most important study ever performed on the subject of natural bodybuilding.
Dr. Casey Butt analyzed the numbers of 300 natural bodybuilding champions who competed between the years of 1947 and 2010. It should be emphasized that this data pool is comprised of champions; what we would consider the top of the genetics pool. These individuals were not mediocre, run of the mill journeymen bodybuilders.
Numerous factors were analyzed: weight, body fat percentage, lean body mass, height, bone structure, wrist size, ankle size, etc. After compiling the data, Dr. Butt was able to develop a highly accurate formula that is capable of predicting the natural bodybuilding limits (expectations; goals) for lifters.
Here is the formula:
The variables in the formula are as follows:
H = Height in inches
A = Ankle circumference at the smallest point
W = Wrist circumference measured on the hand side of the styloid process.
(The styloid process is the bony lump on the outside of your wrist.)
%bf = The body fat percentage at which you want to predict your maximum lean body mass
Casey Butt has stated that the formula is most accurate when analyzing lifters with reasonable body fat percentages and appropriate bone structures for their heights. Very skinny men with strong ectomorphic tendencies will likely only be able to reach 95% of these predicted standards. On the other end of the spectrum, endomorphic-mesomorphic men with extremely wide hips, larger than normal shoulder structures, larger than normal muscle bellies and small bones structures for their height may be able to exceed these predictions by up to 5%.
Many are quick to dismiss Dr. Butt's formula, believing that there is no possible way for science to predict what can be accomplished naturally. Two important facts should be noted.
No natural lifter, to my knowledge, has every exceeded these standards by more than a statistically insignificant percentage.
When these formulas are used to predict lean body mass for current and past champions, it is incredibly accurate - over and over again.
I must stress at this point that Dr. Casey Butt's work should not be viewed so much as a limitation, but rather a high standard. Only the cream of the crop in the natural bodybuilding realm manage to come close to their "upper genetic ceilings."
Invariably Dr. Butt's study is often met with criticisms such as: I am 280 pounds and 19% body fat. This study is bunk! Over the years I have seen dozens of claims like this. When pictures were provided, it becomes obvious that the individuals in question were dramatically underestimating their body fat percentages.
One only has to compare the physiques of these claimants to John Grimek or Steve Reeves to realize that they do not carry around the same amount of muscle mass. Body fat percentages aside, it makes no sense to claim you are beyond Dr. Butt's natural potential predictions if your physique doesn't have anywhere near the amount of muscle as the best natural bodybuilders in the world.
Muscle mass doesn't lie. If you believe you have exceeded these expectations consider the possibility that your body fat percentage estimation might be dramatically off. There's a good chance that it is.
Dr. Casey Butt features a table on his website, found here, that reveals just how accurate this formula is.
Other Methods of Analyzing Natural Muscle Building Potential
In this section we will look at the models and formulas of other prominent voices in the lifting realm. While some of these viewpoints are opinion, the cumulative conclusion that natural limitations exist should be at least considered.
To ignore some of the most intelligent and experienced industry experts would be foolhardy. The following section contains their opinions, quotes, formulas and tables.
Lyle McDonald Natural Muscle Building Model
Lyle McDonald on natural genetic limitations:
I’d note that while I do believe trainees should simply get into proper training and not worry up front what they may or may not accomplish, I also believe that there are genetic limits set by underlying biology (again, modulated by behavioral choices and patterns). That’s just reality and recognizing them can save people from a lot of mental anguish about what they think they should be able to or could be able to accomplish if they just worked hard enough.
Marc Perry Lean Body Mass Formula
Marc Perry on his method of calculating maximum lean body mass:
I came up with this short hand approach to calculate your maximum Lean Body Mass (LBM). Your LBM is everything in your body besides fat, including your bones, organs, muscle, and blood.
The formula is:
(Your Height in Inches -70) x 5 + 160 = Maximum LBM
A chart based on Marc Perry's formula:
Martin Berkham/Lean Gains Lean Body Mass Formula
Martin Berkham on reasonable expectations and standards:
Suffice to say, the bodybuilders that appear on the cover of muscle magazines serves as poor role models for what's possible without "assistance". Establishing reasonable goals and limits for natural bodybuilders and athletes is important in order to put things into context. A ripped 170-180 lbs is often scoffed at in some circles. You're not "big" until you're 210-220 lbs (or so the talk goes). What these people don't realize is that ripped 170-180 lbs would look very impressive on a guy of average height. In fact, few natural guys will ever achieve those stats due to the consistency in training that it requires.
The formula is:
(Height in centimeters – 100) = Max Body Weight in Kg When @ 5-6% Body Fat
A chart based on Martin Berkham's formula:
Alan Aragon Model
Alan Aragon bases his natural gains model on current weight and how much muscle mass you've already accrued. So if you are a 145 pound beginner, Aragon states that you should aim for a 1.45 to a 2.17 pound gain your first month.
Here is Alan Aragon's natural expectations table:
Dr. Casey Butt's Yearly Standards
We have already looked at Dr. Butt's lifetime natural muscle building expectations. Now I want to change course and present the standards he uses for yearly progress. Here is the formula Dr. Casey Butt presents:
muscle gain in one year = 0.3 × wrist2 × 0.5(no. of years training - 1)
So this means that if your wrist is currently 6.8 inches and you are in your first year of training, you can expect a 13.78 pound muscle gain. A lifter with larger bones, say a 7.2 inch wrist, could aim for 15.52 pounds of muscle during their first year.
Here are yearly expectations for a lifter with a 7 inch wrist:
Year 1 - 14.7 pounds
Year 2 - 7.35 pounds
Year 3 - 3.68 pounds
Year 4 - 1.84 pounds
Year 5 - 0.92 pounds
Mathematically you only need to calculate your first year expectations, and then halve then each year thereafter. To do so you can utilize this simplified formula to calculate year one gains only:
First year muscle gains = 0.3 × wrist2
It should be noted that for underweight individuals first year gains may come at a more rapid pace. It is logical to assume that your body wants to seek a healthy weight for your age and frame, and may allow for additional first year muscle mass increases.
A Meta-Analysis of the Natural Bodybuilding Expectation Formulas and Methods
To compare the natural expectation formulas and models presenting in the previous sections, I want to first start with an example. Let's look at a typical scenario...a 19 year old male, 5'10" in height, 150 pound body weight, 15% body fat, and perhaps naturally small boned with wrists approximately 6.5" and ankles at 9".
Lean body mass will be provided, along with a look at scale weight while at 12% body fat.
Dr. Casey Butt's Formula - 180.5 lean body mass potential, 205 scale weight @ 12% body fat.
Lyle McDonald Model - 171.25 lean body mass potential, 194 scale weight @ 12% body fat.
Marc Perry Formula - 160 lean body mass potential, 182 scale weight @ 12% body fat.
Martin Berkham Formula - 161 lean body mass potential, 182.5 scale weight @ 12% body fat.
Alan Aragon Model - 170.75 lean body mass potential, 194 scale weight @ 12% body fat.
Dr. Casey Butt's Yearly Standards - 153.1 lean body mass potential, 174 scale weight @ 12% body fat.
Dr. Casey Butt's primary formula, based upon the analysis of 300 natural champions, is by far and away the best tool to calculate possible maximum natural potential. This does not mean the other tools and formulas are worthless or inaccurate.
They present reasonable gains standards for most lifters. Being 10 pounds shy of the greatest natural champions of all time still provides you with an impressive amount of muscle mass.
Perry's formula is a little on the light side, but it is a great goal for those of you who have no interest in pure mass, but seek to look fit and semi-muscular.
Berkham's formula is designed to show reasonable standards at 5-6% body fat. I believe it accomplishes what it sets out to achieve. Naturals have a much harder time maintaining lean body mass as they cut to 6% body fat. Because of this, Martin Berkham's standard is a reasonable goal for those of you looking to get ultra shredded.
One fact must not be overlooked: not a single model or formula presented by these experts contradicts Dr. Casey Butt's research. Their experiential knowledge and opinions fall right in line with Dr. Butt's study.
Those dismissing natural muscle building potential as "restrictive" should take note that not a single one of these experts provided you with standards that pushed right up against Dr. Butt's max genetic ceiling. This is noteworthy because it hints at the reality that very few natural bodybuilders reach this level.
Berkham, Perry, McDonald and Aragon each provide you with a goal somewhere in the 80 to 90% of your maximum natural physiological muscle building potential. This is reasonable for 95% of you who are not after the maximum amount of muscle mass humanly possible. For the other 5% of you that want more, there is nothing holding you back but time and effort.
Factors That Limit Natural Muscle Building
Let's face reality here for a moment. The belief that you can get as big as an IFBB pro if you only try hard enough, and train long enough, is utter bunk. If this were the case, lifters would not resort to steroids.
There is enough proof in the natural bodybuilding world to destroy this belief without getting into the science of natural physiology. I have talked to dozens upon dozens of natural champions in my day. Most of these men have trained anywhere from 10 to 25 years.
To a man they will tell you that gains slow down dramatically after the first several years. If you look at their contest weights, you will find a trivial difference year in and year out.
Furthermore, if you analyze the competition weights of natural pro bodybuilders you will find they mostly compete within 170 to 185 pounds on stage. Some of the taller lifters and elite champions push beyond 190 pounds on stage, but this is somewhat rare.
If you don't believe me I challenge you to attend several natural bodybuilding events held by federations that are diligent about drug testing. You will find the vast majority of competitors hovering between 155 to 170 on stage.
Compare this to the Mr. Olympia and you find that the natural competitors are weighing in about 100 pounds less. 100 pounds. Let that sink in for a moment.
Drugs permeate the muscle building world for one reason and one reason only: they work, and work well.
So the obvious question is: why are naturals limited with how much muscle they can build? There are 6 primary reasons.
Steroids increase protein synthesis rates.
Steroids induce a greater average positive nitrogen balance.
Human growth hormone allows for the creation of new muscle cells.
Steroids work to block the impact of cortisol on muscle tissue.
Steroids improve creatine phosphate synthesis, which can be beneficial when attempting to re-open sensitized muscle tissue receptors.
Steroids improve the ratio of testosterone to myostatin, allowing for greater potential muscle size.
Natural Testosterone & Human Growth Hormone Levels
Steroids increase bodily testosterone levels to supra-natural, helping to create elevated protein synthesis levels. This allows for greater muscle size.
Human growth hormone creates new muscle cells. This, in concert with elevated protein synthesis levels supplied by steroids, can create cartoon-like levels of muscle mass that no natural can possibly come close to.
Flipping this coin over, it is logical to assume that natural testosterone levels will only allow for a finite level of protein synthesis and muscle tissue growth. Testosterone has a direct impact on muscle protein synthesis. Protein synthesis promotes muscle growth and repair.
A steroid using bodybuilder can maintain highly elevated protein synthesis levels, allowing for greater growth. On the other hand, natural lifter are able to raise a muscle's protein synthesis levels through training, but they return to baseline levels typically within 48 hours.
Anabolic steroids also work to block some of the impact of cortisol on muscle tissue, which works to slow the rate at which existing muscle tissue is broken down. Also, steroids work to increase creatine phosphate synthesis. This allows lifters to train longer and harder.
This benefit in and of itself does not directly cause growth, but it can work to stimulate or repair damaged muscle tissue receptors, thus allowing for improved mass gains. A quote from An Interview With Dharkham, an expert on the workings of anabolic steroids:
When too much androgen is present in the blood, androgen receptor levels will decrease. But we have many studies showing that training a muscle will renew those receptors. This is why why there is a synergy between androgen and training in bodybuilders while steroids only work to a limited extent in untrained persons.
A bodybuilder who has never taken steroids does not suffer much androgen receptor downregulation. Training will simply increase the number of ready-to-work androgen receptors. He will have far more receptors than the average untrained Joe. This is why the first cycle of anabolics is very often the best. Plenty of receptors. As the cycle continues, the number of androgen receptors will go down. But with proper training targeted at re-opening the androgen receptors, we can prevent the stagnation we see in numerous western bodybuilders after several drug cycles.
Long story short, steroid use over time downregulates muscle cell receptors, decreasing results. Intense contractions and/or high volume training sessions can work to re-open these desensitized receptors, working to create better gains. Therefore, improved creatine phosphate synthesis allows a steroid using bodybuilder to increase his likelihood of re-opening these receptors.
Nitrogen Retention
Anabolic steroids also increase the body's ability to retain nitrogen, thus creating a greater average positive nitrogen balance compared to their natural counterparts. A positive nitrogen balance allows for muscle tissue growth.
Natural Myostatin Levels
Myostatin is a protein found mainly in muscle tissue cells. Myostatin deficiencies, or substances that are able to block the activity of myostatin, would allow for greater muscle tissue size.
Testosterone functions sort of like a car's accelerator, while myostatin works like a car's braking system. Muscle gains for natural lifters are regulated because of the ratio between natural testosterone levels and natural myostatin levels.
Bodybuilders using steroids are able to increase the testosterone to myostatin ratio (using our analogy, they can apply more gas), allowing for a much greater muscle mass potential.
Opposing Viewpoints and Arguments
Christian Thibaudeau - "In my opinion if the average trainee would get his nutrition, training and restoration habits in order he could realize drug-like gains. Everybody can build 1lbs of muscle every 2 weeks if everything is done perfectly. This represent a 26lbs gain within a year.
Obviously the more advanced you become, the harder it is to gain muscle or strength ... otherwise we would all be a lean 300, bench pressing 1000lbs after 10-15 years of training!
But IMHO this slowing down in progress is partly due to staying with the same training parameters you used when you started out. Advanced athletes require higher tension (heavier weights or faster lifting) to grow maximally. Training below 80% will do little to improve muscle mass and strength in the advanced lifter."
Chad Waterbury - "Exogenous illegal substances are used because trainees are impatient with their progress, and/or they're unwilling to totally revamp their lifestyles. The same is true with bodybuilders who seek the most mass possible.
To sum it all up: I don't believe steroids and GH break through the ceiling of genetic capabilities; they only accelerate the process, temporarily."
Skip LaCour - "When is a physique considered too good to be natural? That depends on the belief system of the person who’s forming the opinion. I have seen guys weighing 130 pounds to 230+ pounds, ripped and not so ripped, and genetic freaks to genetic inferiors get accused of using drugs. There seems to be no rhyme or reason."
Supporting Viewpoints and Arguments
Lonnie Lowery, PhD - "For biological reasons I disagree with those who believe that a lifelong natural guy can eventually achieve the same muscle mass and hardness as a hormone user (AAS, GH, insulin, growth factors, adrenergics, etc.). It's not as simple as just working harder or longer or smarter, or wanting it more, unfortunately. (Actually wanting and enjoying realistic mass and hardness is smartest, rather than oggling muscle magazine covers, as I'm sure we agree.) But I do totally agree that almost every natural athlete has stones left unturned. Stones that would get him in significantly better shape than he is presently."
Matt Perryman - "Physiology is made up of some hard rules. Without drugs in the mix, further growth is just not likely to happen – and this probably explains why any attempts to “bulk” just result in me getting fatter. My body just doesn’t want to gain any more mass. It’s about as impressive as I can make it, in terms of muscle mass, without heavy drug use."
A Look At Current Natural Bodybuilding Champions & Pros
Let's take a look at current elite level bodybuilders and see how they stack up compared to predicted lean body mass standards.
These natural bodybuilders have won state titles, pro cards and even the prestigious Yorton Cup, yet not a single one of them has busted beyond their lean body mass potential range as predicted by Dr. Casey Butt. They also have not exceeded the lean body masses of naturals who competed 40, 50 and even 60 years ago.
Times have changed, and while modern physiques are leaner, they are not bigger.
Natural Arm Size Potential
Natural arm size potential is another very heated topic. When reasonable standards are presented they are often ridiculed as being too small. It seems everyone on the Internet claims to know someone who is lean and has 20" natural arms.
Despite these claims, pictures never surface. If they do the individual is typically over 35% body fat and far from lean.
The arm size standards in this section are presented as reasonable goals for lifters who are at 15% body fat or lower. As your body fat levels increase, so will your arm size. Add the following adjustments to your arm size goal if your body fat percentage is above 15%:
15% - No adjustment
20% - Plus 0.5"
25% - Plus 1.0"
30% - Plus 1.5"
35% - Plus 2.0"
40% and over - Plus 2 to 3"
These adjustments will help you to create reasonable goals based on body fat percentage.
Calculate Potential Arm Size - Wrist Method
Measure your wrist size in inches right below the ulnar styloid process. This measurement will be to the hand side of the ulnar styloid process, and not the forearm side,
Now, take this measurement and add 10" to it. The next step is to add in a final adjustment based on body fat percentage, using the chart above.
So, as an example...if your wrist measures 7.5" and you are currently at 20 percent body fat, your potential natural arm size would be:
7.5" wrist + 10" + 0.5" body fat adjustment = 18" arms
A reasonable goal for you to aim for at this body fat percentage would be 18 inch arms. This is not to say you will reach this degree of arm size if you keep training, but you should at least come close. (In the ball park, within shouting distance, etc.)
The following chart compares wrist size and body fat percentage to provide you with natural arm size goals.
Arm Size And Big Lies
More bodybuilders lie about arm size than any other body part (combined). If you trust everything you read and hear about arm size, then you likely believe that 20" arms come easy for lean individuals. Perhaps you also believe they require little time and effort.
Nothing could be further from the truth.
Most competitive natural bodybuilders I have met or profiled sport 16.0" to 17.5" arms while in competition shape. I've never seen an 18" inch arm on a stage ready, natural bodybuilder. This is not to say arms this big don't exist, but rather they are extremely rare.
You are likely to only find 18" arms on a lean lifter if he is either tall and big-boned, or elite level. On the other hand, I've met quite a few men at 30 to 40% body fat with 18, 19 and even 20" arms. I myself have reached 18.75" arms as a small-boned lifter, when at higher body fat levels.
These numbers are measured with the arm flexed, but not pumped. Pumping up your arms can add some temporary size.
Many respected bodybuilders have exaggerated their arm size over the years. Arnold Schwarzenegger claimed to have 22" or 23" pythons. Nautilus founder Arthur Jones was able to tape the Austrian Oak's arms and found them to be 19.75" pumped.
Arthur Jones was also able to measure the arms of Sergio Oliva at 20.125". Sergio was one of the few bodybuilders from his era that had true 20" guns. In fact, Arthur Jones has stated that Sergio had the largest arms he had ever measured personally.
20" arms are more common these days. Expanded drug use is pushing muscle mass and arm size up and up. Ronnie Coleman was said to have 22" arms during his peak. This is certainly possible, and highly probable. Ronnie Coleman also competed on stage at nearly 300 pounds.
The Reality of Diminishing Arm Size Progress
As the human arm grows bigger and bigger, it becomes more difficult to add each addition inch. If we look at the circumference of a circle, we find that with each additional inch the area grows by a greater degree. Obviously the arm isn't a perfect circle, but this example does hint at the reality that each additional inch of arm size becomes more and more difficult to achieve.
Here are the areas of circles ranging from 10 to 22 inch circumferences. This example will reveal how much additional arm area is required to gain an extra inch depending on your current arm size.
10 inch arm = 7.94 area
11 inch arm = 9.62 area
12 inch arm = 11.46 area
13 inch arm = 13.46 area
14 inch arm = 15.62 area
15 inch arm = 17.94 area
16 inch arm = 20.42 area
17 inch arm = 23.06 area
18 inch arm = 25.77 area
19 inch arm = 28.71 area
20 inch arm = 31.81 area
21 inch arm = 35.07 area
22 inch arm = 38.49 area
Plotting the data, we see that the ratio of arm size to arm area is not linear. Simply stated, with each additional inch you are required to add more arm area. When growing from 13 to 14" arms, your arm size area must increase by about 2.16. When growing from 19 to 20" arms, your arm size much increase by about 2.94.
If you consider the fact that gains slow dramatically over time for naturals, it becomes apparent that moving beyond a 16 to 17" arm in a lean body state is test of patience. It will take time, time and more time to see small but noticeable increases in size.
The Reality of Somatotyping
You may have never heard of the term somatotyping, but it's likely you know whether you're an ectomorph, endomorph or mesomorph. Most lifters have taken the time to research body types and believe they know which category they best fit into.
Before we go into detail about which somatotype you may be, let's take a detailed look at the mechanics and history behind this concept.
In 1954, William Herbert Sheldon released his book Atlas Of Men which presented the concept of somatotyping. Somatotypes were a method of describing the human body based on several characteristics including:
Muscle length
Muscle belly size and shape
Limb length
Fat storage tendencies
Muscle building tendencies
Waist size
Shoulder size (broad/narrow shoulders)
Bone size
Sheldon went on to detail 3 very distinct somatotypes. Here are the definitions via Wikipedia:
Ectomorphic: characterized by long and thin muscles/limbs and low fat storage; usually referred to as slim. Ectomorphs are not predisposed to store fat nor build muscle.
Mesomorphic: characterized by medium bones, solid torso, low fat levels, wide shoulders with a narrow waist; usually referred to as muscular. Mesomorphs are predisposed to build muscle but not store fat.
Endomorphic: characterized by increased fat storage, a wide waist and a large bone structure, usually referred to as fat, or chunky. Endomorphs are predisposed to storing fat.
It has become a common belief in muscle building circles that each of us fits into only one of these somatotypes. Nothing could be further from the truth, nor the intent of Sheldon's system.
We are to be rated as a combination of all 3 somatotypes, somewhat like the numbers on a combination lock. Each of us is assigned a number ranging from a low of 1 to a high of 7 for each body type. A pure ectomorph would be rated as a 1-1-7, a pure endomorph as a 7-1-1 and a pure mesomorph as a 1-7-1.
In reality there are very few "pure" ecto, meso or endos. You are likely to be rated something like a 2-5-3, or a 6-2-2. What most of us think of as a pure ectomorph is in reality an individual with ectomorphic tendencies that outshadow his mesomorphic and ectomorphic tendencies. The same goes for mesos and endos.
William Herbert Sheldon also noted that body type tendencies could be masked by situational factors. For example, an endomorph who is undereating, or who has a fast metabolism and is struggling to intake a quality amount of daily calories, may start to resemble an ectomorph.
Your somatotype tendency can also be masked by training, current lean body mass and/or body composition. This means that a lifter with ectomorphic tendencies that does everything right in the gym and at the dinner table might be labeled as a natural mesomorph by his peers. On the opposite end of the spectrum, a mesomorph who is putting little effort into his training, and undereating (say with the goal of seeing his six pack abs) might end up looking more like an ectomorph than a meso.
It should be obvious at this point that your somatotype combination can be changed. Bone size and limb length won't change, but body composition and muscularity can morph your somatotypic combination.
Some interesting facts regarding somatotyping should be pointed out. It is up to you to decide their importance and relevance.
William Herbert Sheldon was a psychologist, not a biologist or doctor.
Somatotype combinations were used as a vehicle by Sheldon to determine your personality type.
Those with mesomorphic tendencies were considered likely to commit aggressive and violent actions.
Sheldon's models are based off of male body types only.
Sheldon believed that beliefs, motivation and attitude were rooted in in your somatotype combination.
Many of William Herbert Sheldon's modern peers consider his theories to be not only outdated but verging on quackery.
Does this mean that somatotyping for bodybuilding is useless? No, not really. If we set aside the tie-in with personality tendencies, we are still left with an interesting and somewhat valid system of determining an individual's body type.
On the other hand, the actual determination of the somatotype combination is, by nature, subjective. Advancing this further, the vast majority of those assessing somatotypes do it incorrectly. They are not seeking combinations and looking at patterns and tendencies, but rather trying to fit each of us into a specific, tidy little box.
The take home point in all of this is simple: don't put your faith in this subjective and misused rating system. Train properly, eat right, remain patient and you will likely exceed your physique expectations.
Most men assume they are hardgainers or ectomorphs way too early in the game. It could be said with a high degree of certainty that the vast majority of these men who believe they are ectomorphs are undertraining, undereating, missing workouts and/or not patient.
Moving Beyond Body Types
We all agree that the human body is a complex piece of DNA-filled machinery. No two individuals are equal, and no two individuals will respond in the same manner to the same training protocol or eating plan.
Furthermore, guessing at how you will respond to training or nutritional changes is typically a fool's game. You are better off making one change at a time and assessing it's impact on your training effectiveness and body composition.
Here are some ways that human beings can differ:
Some of us respond better to high volume, some to low.
Some of us respond better to very basic and straightforward training protocols, while some of us need to get a little more complex and play with the variables.
Some of us build muscle more quickly than others.
Some of us have higher pain thresholds, and therefore might handle certain workout routines a little easier.
We each have unique joint tolerances.
Some of us may be more prone to tendonitis.
Some of us may need to rely more on periodization, while others may not need to periodize for a very long time.
Some of us gain fat more rapidly than others.
Some of us need more time to build up tendon and ligament strength.
Some of us have more efficient central nervous stems and may not require as many warm up sets, while others may need more extended and precise warm ups.
Some of us have big bones and greater natural strength abilities.
We could continue on ad nauseam, but you get the point.
You are a unique physiological entity. Instead of guessing at how you will respond, test things out and evolve your training based on needs and body feedback. Toss out the things that don't work, or don't feel right, and keep the things that help you train better, focus better and build more muscle.
Some of you may need to train squats twice a week using a 5x5 protocol to see quality leg gains. Others may find that they respond to lower volume but higher reps - say a central focus on 20 rep squats.
Understand that I am not advocating "easy training", nor the concept that anything goes. The last thing I am trying to tell you here is that all lifts and programs are created equal. Far from it.
It is best to make tweaks and changes based upon conventional and proven methods. Avoid extremes, like training biceps for 50 sets, 3 times per week.
Focus On What You Can Control
Let's end this article with some practical advice:
Focus on what you CAN control.
You have the ability to train smart and hard. You have the ability to control and modify your diet to seek out better results. Regardless of your genetics, each of us still has no choice but to focus on the things we can control.
Standing in the mirror analyzing your physique isn't going to help you. Even reading articles (like this) isn't going to help you.
Not a single one of us knows what we can accomplish until we try.
Use the expectations and standards in this guide as reasonable goals, but don't get caught up in numbers. As long as you are trying to improve each day, and making intelligent diet and training changes, you are doing all you can.
Stay on that course and remember one important thing: your mental strength and will to succeed are your greatest assets, not your genetics.