Why are all humans not muscular?

[silenzer]

Hi,

Sorry for the recent breaking of the rules. I have now switched my notification of PMs to on, so I won't miss any more PMs.

Why aren't all human beings not more muscular? It's clearly beneficial. My guess is that we began to use tools so soon (1 million years ago?) that the need for muscle didn't arise.

 

[NobodySpecial]

Muscle is expensive, you only have enough of it for your body to function.
If you were built like Arnie you would need 2-3x as many calories each day to survive, would the extra muscle allow you to get 2-3x as many calories?
Most hunter-gatherer people are on the skinny side

 

[SW VandeCarr]

The Neanderthals were muscular. Look what happened to them.

 

[Dr Lots-o'watts]

Roughly, we're born with what we have because our parents managed to make a living with equivalence, and so on with their ancestors, and so on with humanity as a species.

Muscular arms are detrimental if you have to run away from a polar bear. And polar bears can't survive in a jungle. In general, every living thing is adapted to where it's born.

 

[SW VandeCarr]

Roughly, we're born with what we have because our parents managed to make a living with equivalence, and so on with their ancestors, and so on with humanity as a species.

Muscular arms are detrimental if you have to run away from a polar bear. And polar bears can't survive in a jungle. In general, every living thing is adapted to where it's born.

The Neanderthals were well adapted to their European environment until modern humans arrived from Africa via the Mid East. The muscular Neanderthals apparently could not compete against the smaller slighter Cro-Magnon humans and died out. It's not known exactly how this happened but the Cro-Magnons probably had language and could work more effectively in groups. The Neanderthals' vocal apparatus is thought to have been incapable of language and the speech part of their brain (Broca's area) does not seem to have been well developed based on their cranial anatomy.

In any case, their muscles did not help them compete successfully against our ancestors even though it was probably a successful adaptation for hundreds of thousands of years.

 

[DanP]

Do not forget that the humans are endowed by evolution with extreme myoplasticity. This means a simple truth which all posters in this thread forget. Just about every human male (and in slightly lesser measure females) born on this planet have the potential for big hypertrophy of the skeletal muscle mass, and modulation of the expression of strength, speed, power, endurance.

So while you are not born "muscular" , you can easily become.

The average member of the society is not muscular today because they are mainly too busy getting fat in McDonalds. Should they be exposed to harsher environments, or work out, myoplasticity allow for pretty fast adaptive changes. So if you want to be bigger and you are not, it's your fault :P

Also, the figures of 2x, 3x caloric expenditure at the a higher muscle mass presented in this thread are bull. Gross exaggerations.

 

[NobodySpecial]

The average member of the society is not muscular today because they are mainly too busy getting fat in McDonalds. Should they be exposed to harsher environments, or work out, myoplasticity allow for pretty fast adaptive changes. So if you want to be bigger and you are not, it's your fault :P

But the average human in the years BMcD (before McDonalds) still didn't evolve into something that could kick sand in a gorillas face. Our early ancestors weren't much heavier than chimps and even today those people with the lifestyle closest to our ancestors are among the smallest.

the figures of 2x, 3x caloric expenditure at the a higher muscle mass presented in this thread are bull. Gross exaggerations.

A slight exaggeration, but if we had all evolve to have the body mass of gorillas (or olympic weightlifters) we would need several times the calorie intake of the average Kalahari bushman and the extra muscle and strength wouldn't have helped you gather those extra calories.

 

[DanP]

A slight exaggeration, but if we had all evolve to have the body mass of gorillas (or olympic weightlifters) we would need several times the calorie intake of the average Kalahari bushman and the extra muscle and strength wouldn't have helped you gather those extra calories.

You evolved myoplasticity which is much more valuable than a set in stone, cast type musculoskeletal system.

The bottom line here is that you didnt evolved to be a Kalahari bushman at weight, neither a Schwarzi. You evolved with enough plasticity to be both. The take away lesson is that plasticity allow humans to negotiate a much wider range of environments and environmental challenges than simply ... run from bear, hide in Kalahari whatever. Myoplasticity is infinitely more valuable than a forced type of either a scrawny or a brawny. Ofc, individual differences still do exist in how well this plasticity can be expressed.

 

[elginz]

One theory is that early human's success depended on the ability to run down game. Evolving as long distance runners removed the need for massive muscles.

 

[DanP]

One theory is that early human's success depended on the ability to run down game. Evolving as long distance runners removed the need for massive muscles.

Again, you didn't evolved as a long distance runner. The human body is capable of both long distance endurance performance and extremely high power development speed-endurance (a-lactic systems) to run 100m at very high speeds. But the adaptations required are mutually exclusive. I.E, you can't do both well at the same time.

What you evolved is tremendous capacity for myoplasticity. Some populations may be biased toward one side of the spectrum, but still, there is tremendous plasticity involved.

 

[bobze]

The Neanderthals were well adapted to their European environment until modern humans arrived from Africa via the Mid East. The muscular Neanderthals apparently could not compete against the smaller slighter Cro-Magnon humans and died out. It's not known exactly how this happened but the Cro-Magnons probably had language and could work more effectively in groups. The Neanderthals' vocal apparatus is thought to have been incapable of language and the speech part of their brain (Broca's area) does not seem to have been well developed based on their cranial anatomy.

In any case, their muscles did not help them compete successfully against our ancestors even though it was probably a successful adaptation for hundreds of thousands of years.

I think the "slightly smaller" point is a good one to be had, people tend to (in my opinion) exaggerate the musculature of Neanderthalensis. Just one of those "myths" I suppose.

Do not forget that the humans are endowed by evolution with extreme myoplasticity. This means a simple truth which all posters in this thread forget. Just about every human male (and in slightly lesser measure females) born on this planet have the potential for big hypertrophy of the skeletal muscle mass, and modulation of the expression of strength, speed, power, endurance.

So while you are not born "muscular" , you can easily become.

The average member of the society is not muscular today because they are mainly too busy getting fat in McDonalds. Should they be exposed to harsher environments, or work out, myoplasticity allow for pretty fast adaptive changes. So if you want to be bigger and you are not, it's your fault :P

Also, the figures of 2x, 3x caloric expenditure at the a higher muscle mass presented in this thread are bull. Gross exaggerations.

Not adaptive changes, adaptations are hereditary traits favored by selection. We're talking changes within a life-time, not across lifetimes necessarily. These would be extreme acclimative changes.

But I'm not so sure we can just write it off to "human's extreme myoplasticity". Have you ever put an animal on a weight-training regime? All skeletal muscle has the ability to rebuild and repair. Humans have the technology, knowledge (and in some cases knowledge of certain illicit hormones) to "build Arnie muscles". I think (well I know) that if you put a horse or a chimp on steroids and made them workout too, they also can gain much muscle mass-In fact this has been a problem in horse racing for a long time (anabolic steroid use, that is) because the same principles bodybuilders use can be applied to animals.

I think it would be better to say that skeletal (and a less extent smooth muscle) evolved a great deal of myoplasticity in the animal kingdom and probably a greater extent--In mammals and birds, who's tight thermoregulatory and homeostatic controls allow for such developments under certain conditions.

 

[DanP]

Not adaptive changes, adaptations are hereditary traits favored by selection. We're talking changes within a life-time, not across lifetimes necessarily. These would be extreme acclimative changes.

You should know that in exercise physiology , changes in repose to environmental factors in the organism are called adaptations. You may want to know that a term can have multiple definitions, depending the field where it is used. The meaning in exercise physiology is different by the meaning used in evolutionary biology.

The term is correct how I used it. And even a cursory familiarity with both fields would prevent any kind of confusion whatsoever.

 

[bobze]

You should know that in exercise physiology , changes in repose to environmental factors in the organism are called adaptations. You may want to know that a term can have multiple definitions, depending the field where it is used. The meaning in exercise physiology is different by the meaning used in evolutionary biology.

The term is correct how I used it. And even a cursory familiarity with both fields would prevent any kind of confusion whatsoever.

I know it is used differently in different fields. I correct biochemists all the time using it incorrectly.

The point was, it was being used in an evolutionary context. Ergo, since we are talking about the branch of science which studies biological evolution--Not physiology, not biochemistry, not English literature, we should use it appropriately.

And even more so, to avoid confusion on the part of thread participants who aren't as familiar with nor endowed in the knowledge of, the different verbiage. Considering this is a science forum, than using the agreed upon definitions of words relevant to those sciences is probably a wise decision. Hence, my pointing it out.

 

[DanP]

I know it is used differently in different fields. I correct biochemists all the time using it incorrectly.

There is nothing sacred with definitions. The word just carries multiple meanings.

The point was, it was being used in an evolutionary context. Ergo, since we are talking about the branch of science which studies biological evolution--Not physiology, not biochemistry, not English literature, we should use it appropriately.

So what ? Most of the persons I know can very easily distinguish between the evolutionary context and physiological contexts even when term is used with both senses in the same proposition.

And even more so, to avoid confusion on the part of thread participants who aren't as familiar with nor endowed in the knowledge of, the different verbiage. Considering this is a science forum, than using the agreed upon definitions of words relevant to those sciences is probably a wise decision. Hence, my pointing it out.

This is the only valid point you raised regarding the usage of the word.

 

[bobze]

There is nothing sacred with definitions. The word just carries multiple meanings.

Dan, not sure why you're being so defensive. I'm not trying to debate you here, I was simply pointing out the correct usage of the word in an evolutionary context.

So what ? Most of the persons I know can very easily distinguish between the evolutionary context and physiological contexts even when term is used with both senses in the same proposition.

This is the only valid point you raised regarding the usage of the word.

And I as well, for most of the people I am around from day to day are medical students or graduate students with backgrounds in natural sciences. Likewise, many of my friends, whom I became friends with during my undergraduate years have educations in the natural sciences and would also understand what you meant (as I did).

The point is though, that is a generalization. This is an online community with people from all walks of life, some don't even use English as their first language. Others last natural science class may have been in high school years ago. As part of this websites goal; to provide education of the sciences discussed (though the moderators can correct me if that is not part of this websites purpose), and built upon that premise, I thought it acceptable and prudent to clarify. No harm, no foul.

 

[Evo]

I know it is used differently in different fields. I correct biochemists all the time using it incorrectly.

The point was, it was being used in an evolutionary context. Ergo, since we are talking about the branch of science which studies biological evolution--Not physiology, not biochemistry, not English literature, we should use it appropriately.

And even more so, to avoid confusion on the part of thread participants who aren't as familiar with nor endowed in the knowledge of, the different verbiage. Considering this is a science forum, than using the agreed upon definitions of words relevant to those sciences is probably a wise decision. Hence, my pointing it out.

This is correct bobze. Thank you for pointing out the correct word.

 

[Raphie]

The muscular Neanderthals apparently could not compete against the smaller slighter Cro-Magnon humans and died out.

The Neanderthals were not just competing against Cro-Magnons, but also against the elements, regardless of whether or not the following study is in some manner reflective of objective reality...

Volcanoes Wiped out Neanderthals, New Study Suggests
ScienceDaily (Oct. 7, 2010)
http://www.sciencedaily.com/releases/2010/10/101006094057.htm

 

[Evo]

The Neanderthals were not just competing against Cro-Magnons, but also against the elements, regardless of whether or not the following study is in some manner reflective of objective reality...

Volcanoes Wiped out Neanderthals, New Study Suggests
ScienceDaily (Oct. 7, 2010)
http://www.sciencedaily.com/releases/2010/10/101006094057.htm

They might have wiped out a small pocket of neanderthals in a small area, but there is pretty much undisputed evidence of neaderthals dated from between 28,000 to 30,000 years ago in other areas.

Clive Finlayson from the Gibraltar Museum and his colleagues found Neanderthal artefacts in a site called Gorham's Cave. The dig there has so far unearthed 103 items, including spear-points, knives and scraping devices, bearing the marks of Neanderthal craftsmanship. Radiocarbon dating suggests that most of the objects are about 28,000 years old, with the youngest being 24,000 years old.

He adds that a large number of the artefacts in Gorham's Cave date from 30,000-31,000 years ago, which he thinks may be more representative of the samples. That wouldn't make it the youngest Neanderthal site.

http://www.nature.com/news/2006/060911/full/news060911-8.html

And more recently

The recent redating of a Neandertal jaw and a cranial fragment--found in a cave at Vindija, Croatia, in the 1970s and 1980s--to ca. 28,500 years ago makes them the youngest Neandertal fossils ever found in Central Europe, according to anthropologist Fred H. Smith of Northern Illinois University and his colleagues, who published their findings in the October 21, 1999, edition of the Proceedings of the National Academy of Sciences. Paul Pettitt and colleagues at Oxford University determined that the two bones are between 28,000 and 29,000 years old using accelerator mass spectrometry radiocarbon dating.

http://www.archaeology.org/online/news/neandernews.html

 

[arildno]

Remember that a single gene is likely to contribute (or hinder) to many traits in a human being, not just one.

thus, it might be that those combinations of genes that are involved in the build-up of muscle might have inhibitory effects on other traits.

If those traits are can be at least as adaptively important, or more important, then it is no reason why a "strictly good" trait as muscles should become a uniformly distributed trait amongst humans.

 

[SW VandeCarr]

I think the "slightly smaller" point is a good one to be had, people tend to (in my opinion) exaggerate the musculature of Neanderthalensis. Just one of those "myths" I suppose.

I think this link goes along with a consensus that the Neanderthals were quite muscular, somewhat shorter and stockier than modern humans, and possessed slightly larger brains (surprisingly). The Cro-Magnon advantage was likely language and the related ability to organize hunts for large prey as well as to possibly to organize attacks against Neanderthal competitors.

http://www.pbs.org/wgbh/evolution/humans/humankind/n.html

 

[bobze]

I think this link goes along with a consensus that the Neanderthals were quite muscular, somewhat shorter and stockier than modern humans, and possessed slightly larger brains (surprisingly). The Cro-Magnon advantage was likely language and the related ability to organize hunts for large prey as well as to possibly to organize attacks against Neanderthal competitors.

http://www.pbs.org/wgbh/evolution/humans/humankind/n.html

I agree SW. Certainly the evidence supports that Neander-man was stockier and of a generally more muscular build to the extant Homo sapiens of the day.

I was just pointing out that people tend to over exaggerate this build, as poor Neander-man has been over exaggerated extensively since his discovery.

Obviously the denser bone structure would entail larger musculature, but I think the product of their strength was likely a consequence of their bone-structure, rather than a the other way around (in that that need was for moving those dense bones, which they still appear to have broken often).

How strong were they? I don't know and it maybe one of those unanswered questions. I don't think they could walk into an amateur weight lifting competition and compete, if that is what people mean by "strong".