Somatotypes Theory

Somatotypes Theory

Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.


What are some of the most common "body types"?

We often worry about the shape and size of our bodies, and particularly if you are an athlete, and are wanting to perform better.

If you take a look at your chosen discipline, you may find that your competitors have a similar body shape.

Take a look at sprinters, marathon runners or cyclists. And, at the other end of the scale sumo wrestlers look like their peers, as so swimmers. 

William Sheldon first introduced somatotypes into American psychology in the 1940s.

He believed that body shapes and proportions were linked with psychological traits and behavior and morality were determined by physiological makeup; consequently he proposed constitutional psychology based on genetic predisposition to various moralities and personalities in individuals of certain body types.

His ideas became heavily influenced by eugenics movement but have since been disproved by modern science.

Therefore, does body shape matter, and can it provide a competitive edge?

In this article we shall cover the following key points:

  • What is my body type? Can I change it if I want to?
  • What is the importance of my body type for training?
  • Body Types and Training Results
  • Strengths and weaknesses of training according to body type
  • Balanced body types

What are the differences between body types?

It's common to describe our bodies in recent years. You've heard all the terms: curvy, athletic, and muscular. 

While some body types are relatively new, the concept of labeling our build has been around for many decades. 

The debate over whether body type is important for training has been raging. People have polarising opinions on this subject. Others believe that body type is a major factor in the way we train. 

What are the 3 body types? Will knowing these help you improve your results in training? Here we will discuss three body types and the science of body types to help you make an educated decision. 

What are the main "body types"?

The Oxford Dictionary defines body types as "a group of people who are classified according to how closely their physical characteristics match a standard type". 

These are:

  1. Ectomorph
  2. Mesomorph
  3. Endomorph

Your somatotype can be defined as a classification of your appearance. The body type is based on body mass, muscle density, and body structure. 

William Sheldon, a Dr. in the 1940s, was one of the first to introduce somatotypes. 

In his original theory, he suggested that a person's personality can be related with their somatotype. 

Bodybuilders, personal trainers and nutritionists frequently discuss three general body types - ectomorph, endomorph and mesomorph - known as somatotypes in fitness circles.

Each body type - often called "somatotype" - can be distinguished by its shape and weight distribution: Ectomorphs are long and lean while endomorphs have round structures with higher fat percentages, and mesomorphs feature muscular physiques.

Although the original theory is unfounded, there have been studies to better understand how somatotypes affect our health. 

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The three types of body type.

W.H. Sheldon created the Somatotype Classification System during World War II to link certain personality traits with physique types, creating three generalized body types based on these.

He termed these categories Ectomorphy, Mesomorphy and Endomorphy; although his constitutional theory has since been discredited; still classifying people according to their physique does provide some useful insight.

For example, in his system Endomorphs were described as cheery and relaxed while Mesomorphs as active and competitive while Ectomorphs as introverted yet intelligent and restrained; Sheldon predicted that personality traits would also be affected by one's Somatotype.

Somatotypes are determined primarily through physical measurements like height and weight, arm and leg circumferences, muscle thickness of triceps and biceps muscles, hip widths and ankle widths, as well as skinfold thickness measurements taken with an anthropometer set and recorded by a certified physiotherapist.

In the 21st century, we use many different terms to describe body type and composition. 

We'll look into each type of body in more detail. 


Ectomorphs have long, slim limbs with minimal muscles development compared to their fellow players and often appear wiry or willowy.

Their bodies tend to be lean naturally and may struggle with adding muscle mass; therefore it is important for an ectomorph to get enough calories in their diet to help build it up and add muscle mass.

Ectomorphs also tend to have higher metabolisms and don't gain weight easily making them good candidates for endurance sports such as marathon running or swimming; their natural grace allows them to thrive when competing at racquet sports where their long limbs don't seem fully developed unlike their fellow players'.

If you are an ectomorph, resistance training twice every week should help to build muscle mass and increase bone density. You can do this type of workout using a pyramid rep structure; beginning with lighter weights before moving up to heavier ones.

Resistance training can also help you burn fat more efficiently - this is particularly true if you are an ectomorph as their metabolism tends to be faster.

Understanding your somatotype can be one of the best ways to understand how your body works and which exercises and diet will best benefit you.

But it is important to remember that body shapes can change over time; for instance, becoming inactive or gaining too much weight might change from mesomorph to endomorph somatotype status.


Body type can make or break someone's fitness goals. While some struggle to gain lean muscle mass and are frustrated with their lack of progress at the gym, others see great success when making modifications to diet and training regimen.

Understanding which body shape and composition best suit each person helps set realistic health and fitness targets. 

Mesomorphs are distinguished by their muscular build and athleticism. Their bodies boast narrow waistlines, hiplines and wide shoulders - giving them an attractive physique - while fat storage/burning abilities make them excellent runners over short distances such as sprinting/track workouts.

Mesomorphs also excel at triathlons because their upper-body strength allows for propelling through water while their legs allow cycling/running more effectively.

Though somatotype has been linked with endurance sports (e.g. swimming and endurance training), it has yet to be demonstrated that it affects strength-based exercises.

This may be because somatotype does not correlate directly with basal metabolic rate - which provides a more accurate indicator of metabolism. One Korean football study demonstrated this by finding goalkeepers had higher BMR than other positions but were of equal somatotype.


Endomorph body types tend to be heavier than others but not necessarily obese, and have higher metabolism than ectomorphs; however, they have trouble losing weight due to storing fat easily.

Luckily, an endomorph body type can be transformed with special diet and exercise plans; celebrities like Marilyn Monroe and Oprah Winfrey often opt for such body types in the entertainment industry. 

What is my body type and can I change it?

The majority of people do not fall under a single body type. Our body types change over time. You're likely to fall into two different body types at some stage. 

The genetics of our body types is a major factor. The twin studies that investigated the three somatotypes concluded that the body types in both the ectomorphous and mesomorphous categories have high heritabilities. Our body types can also be affected by age and gender. 

We have no way to control our body types due to the genetic influences on them. 

But, body types do often change over time. Our bodies, for example, can change dramatically once we hit puberty. This is especially true when it comes shape and percentage of body fat. 

A study of body types in males found that they become endo-mesomorphs in late teen years and their twenties compared with being ectomesomorphs in earlier adolescence. 

What is the importance of my body type for training?

Bodybuilders and personal trainers frequently cite the Somatotype System to explain how an individual's build may dictate their success in building muscle or losing weight or simply maintaining fitness levels.

Body composition depends heavily on lifestyle choices and habits.

A person who follows a nutritious diet, avoids junk food and respects their body will have greater success developing muscles, burning fat and building lean muscle mass regardless of somatotype.

Conversely, those who follow poor diet and lifestyle habits will struggle to reach their goals due to both poor habits and their somatotype.

Somatotypes provide useful information in selecting an individual training program and should therefore be used when developing training plans for everyone.

It is crucial to consider how your body type can affect health and fitness, particularly if you are aiming for specific goals. 

It is easier for somatotypes with a mesomorph body type to build muscle. With a regular training program, those with mesomorph bodies will likely experience faster (and easier) muscle gains than their ectomorph and endomorph counterparts. 

Ectomorphs may have a harder time building muscle. You're likely to find mesomorphs or endomorphs in heavier weight classes. 

The Relationship Between Body Types and Training Results

Research has demonstrated a correlation between somatotype and physical performance.

This may be the result of genetic influences acting upon both traits; however, environmental influences also likely play a part in their correlation.

One twin study concluded that certain components of somatotype had strong positive associations with cardiovascular and muscular strength as well as motor ability - although its relationship to cardiorespiratory endurance endurance was weaker.

Somatotype has also been found to correlate with various athletic performance measures, including speed and agility.

Tests that assess this correlation include 20-meter sprint tests, sit-up and crunching tests, push-ups, vertical and standing long jump tests, hand-eye coordination exams and limb movement speed assessments.

Furthermore, research suggests somatotype can predict OSAS symptoms; however studies investigating its link to OSAS remain limited.

Somatotype and athletic performance are closely interwoven; however, no single somatotype can determine which sport would best suit an individual.

Instead, it is crucial that people select activities which meet their physiology, while being prepared to adapt training regimens according to body type.

An experiment was carried out comparing Italian and Estonian schoolchildren aged 6-11, using Heath-Carter anthropometric somatotyping methods, to investigate how organized physical activity and sport practice affect variations in somatotype.

Each child was then scored using one-way ANOVAs or factorial ANOVAs depending on country-related variations in somatotype components, while forward stepwise discriminant analyses were then applied in order to find optimal classifiers.

Results demonstrated that mean somatotype components differed between countries - Italy were significantly more endomorphic while Estonian children had less mesomorphic traits.

A study of Ironman events found that the somatotype had a greater impact on final results than any training program. 

The results of this study showed that endomorphs performed better in the first phase of the race, while the effects of somatotype were most evident during the second. 

This study shows that your body type has an enormous impact on your training. 

Your body type should not stop you from achieving a specific training goal. 

Knowing your somatotype will help you to understand your natural body type for certain sports, activities and training plans. 

Train Strengths and Weaknesses Depending On Body Type

Being leaner is a great advantage for mesomorphs. Ectomorphs might find it easier to do aerobic exercises, while building muscle may require more effort. 

You'll likely see more results if you are an endomorph. When it comes time to achieve aerobic goals, however, you may need more patience, and perhaps a more tailored plan. 

The Balanced Body Types

In the world of health and fitness, there is criticism about putting too much focus on training results and somatotype. 

Too much focus on your somatotype may lead to unhealthful body problems, like body dysmorphia and eating disorders. It's important to consider the impact of your somatotype when evaluating training results. 

Understanding your body type will improve your ability to gain mass and reduce excess fat. You should only use the body type as a guide, not as an end-all solution to training. 

Consistency, proper rest periods and the correct nutrition are key. 


William Sheldon first introduced the Somatotype concept during World War II by connecting physical traits to personality traits.

For example, long and lean ectomorphs he believed were likely to be sensitive, introverted and shy while muscular mesomorphs could be active, assertive and competitive.

Rounded endomorphs on the other hand were believed to be extroverts with cheerful dispositions characterized by laziness or excess.

His ideas proved controversial and led to constitutional psychology which later fell away as it was found to be racist eugenic ideology-influenced and misrepresented as constitutional psychology was abandoned as racism is.

However, there is much discussion to how your somatotype has been shown to influence your training results. Every somatotype has its advantages and disadvantages related to certain types of training. 


Ectomorphs have a more delicate, thinner body. Ectomorphs are thinner and have less muscle than other body types. This category includes people who struggle to gain or maintain weight, and are sometimes even underweight. 


The 'middle category' of the somatotypes is a mesomorph. A mesomorph is a person with a medium body weight and athletic ability. It is easier for them to gain or lose weight, and they have less trouble with it. 


A body with an endomorphic structure is larger and has a more fuller body. It is easier for them to build muscle and achieve their goals in strength training. They may also struggle with weight loss as they carry more fat. 

You shouldn't use your somatotype to determine your fitness and strength goals. Know your body type and set realistic goals. Then, develop an effective training program that will result in steady progress. You can do it. 

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