Recently I have been working on a story that features a pop star who is actually an alien super soldier raised by human parents. That is to say, she was genetically engineered to be a biological killing machine, but turned out instead to be a pop sensation thanks to her good looks, heightened learning ability, and enhanced creativity (Among other things).

I imagine her to be physically proportioned like Taylor Swift, or Rihanna or [insert other female celebrity icon]. So she is not particularly well-muscled, at least not visibly so.


Could genetic engineering dramatically increase the strength of a person without visually affecting their outward appearance?

Specifically is increased strength by a factor of 10 feasible, given gene-editting, without a visual increase in size? (It is alright if it requires increased density and thus weight, or various hidden structural changes)

Also, if not a factor of 10, then what lower numerical value would make sense? (x2, x4, x5, x8?) Could it be higher? I am aware that Superman level strength is probably impossible given physics, but what is the limit of organic muscle given the cross-sectional size of the average human arm?

I would like to stick to hard-science, but given that genetic engineering is in its infancy, I understand some things are speculative.

Additional Info:

The following are additional thoughts and ideas that come to mind related to the topic. They are possible future questions, but not the main question of this post.

I have read in several places, that chimps, despite being smaller than humans, are pound for pound stronger than us. Sometimes this is chalked up to no restraint as a chimp can fly into a primal fury much more easily than a modern human. But other times this is actually spoken about as physiological difference in the structure of the muscles between the two species. Could muscle design produce the pop star super soldier I am envisioning?

Another note is that in researching artificial muscles, I came across experiments in using spider silk to produce muscles that performed many times better than the fibers present in human muscles. Now they did not recreate an entire arm or anything, but they did do tests lifting small weights and comparing the values human muscles fibers are known to be able to manage. Could a super soldier be designed, through hard-science genetic engineering, to possess muscles made from other organic materials and end up visually no different than a normal human, but physically much stronger? I know this can obviously happen in fiction, but I am asking is this something that science could actually accomplish in theory.

When it comes to genetic engineering, I tend to think of things that are in nature already, and the idea that if they can exist on other animals, then it is within the realm of physics to add them to humans. I understand there may be a trade off, but I am more asking if it is possible rather than what are the consequences the individual would have to live with, so long as they are not horribly impaired or anything.

The character is an "alien" but mostly in the foreign sense, biologically the character is very human aside genetic alterations to the genome to accomplish desired results. Imagine human being the template, then edits take place to create the alien.

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    $\begingroup$ Welcome to WorldBuilding Eso Di! Very cool first question, but please note that you should stick to one question per post. You can always ask additional questions later and just link to previous questions. For example the stuff up to "Additional info" is obviously one question with a few things to consider, but the part about creating muscles out of some different material look like a different question as it's know. Could you edit your post to highlight which is the question and which are just "things to consider"? If you have a moment please take the tour and visit the help center.Have fun! $\endgroup$
    – Secespitus
    Feb 6, 2018 at 14:47
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    $\begingroup$ Chimps are indeed much stronger than humans at the same weight. That is because humans are adapted to be able to run for a long time without running out of breath. That is, chimps sacrifice endurance for short-term strength, humans sacrifice short-term strength for endurance. There is no free lunch. A human with the muscular strength of a chimpanzee would need much stronger bones (so they don't get broken by their own muscles) and would have limited effort endurance (because the lungs won't be able to supply enough oxygen to keep the muscles in aerobic mode). Your pick. $\endgroup$
    – AlexP
    Feb 6, 2018 at 14:53
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    $\begingroup$ Three possible duplcates: worldbuilding.stackexchange.com/questions/72291/…; worldbuilding.stackexchange.com/questions/56245/…; worldbuilding.stackexchange.com/questions/51181/…; You should specify how your question is different from all these. $\endgroup$
    – kingledion
    Feb 6, 2018 at 14:53
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    $\begingroup$ @kingledion Where should I make such a specification? I think the main difference is that I am inquiring about Strength enhancement without visible size or bulk, where as the other super soldier and superhuman questions do not discuss keeping the subject the same size as normal humans. $\endgroup$
    – Eso Di
    Feb 6, 2018 at 15:07
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    $\begingroup$ @kingledion This question is focusing on humans that look like female celebrities - not hulking ""Captain America"-like soldiers as the first link mentions. The second one wants a monster that can shrug off being hit by a bullet, whereas this one focuses on being stronger, but not visibly different. The third one wants James Bond after years of military training - but without any genetic modifications. I don't know why the second one is marked a duplicate of the third one and I don't see how any of those questions answer this one. They are all interesting and related, but not a duplicate. $\endgroup$
    – Secespitus
    Feb 6, 2018 at 15:09

2 Answers 2


We could revert our muscle genes to the muscle genes in our primate relatives, and so be as strong as they are.

Humans are weaker than our primate cousins like chimps and orangutans.


Our early ancestors likely possessed apelike strength, at least for the skeletal muscles analyzed in the new study. Today our brawn is much reduced, while other body tissues, like kidneys, have remained relatively unchanged over millions of years. Over the same time period, the brain evolved four times faster than the rest of the body. ... He notes that "human muscle has changed more in the last six million years than mouse muscle has since we parted company from mice back in the early Cretaceous." That was about 130 million years ago.

To confirm their findings, which were based on analysis of 10,000 metabolic molecules, the researchers pitted people, chimps, and macaques—another kind of monkey—against each other in a contest of strength.

All participants had to lift weights by pulling a handle.

"Amazingly, untrained chimps and macaques outperformed university-level basketball players and professional mountain climbers," Roberts says. People were indeed only about half as strong as the other species.

The weakness has to do with all of our muscles - although in trade humans have considerably more endurance than do our primate cousins. I am pretty confident that Taylor Swift could outlast any nonhuman primate in a marathon. I could not find that the specific mutations behind human weakness have been identified, although the specific reason has been identified for human jaw muscles: we have a mutation in a gene that leaves our jaw muscles weak.


Hansell Stedman, a gastrointestinal surgeon at the University of Pennsylvania in Philadelphia and his colleagues came across what appears to be one such gene by accident in their studies of the genetics of muscle movement. The new gene, MYH16, codes for a myosin. When the researchers compared it to the same gene in gorillas, chimps and other non-human primates, they found the human one had a flaw that resulted in a shorter-than-usual MYH16 protein and relatively weak muscles, they reported in the 25 issue of Nature.

Stedman and colleagues dated the origins of the mutation by comparing difference between the human gene and that of other primates. This molecular analysis indicates that the mutation appeared 2.4 million years ago, about the same time that human evolution took off. Stedman proposes that because of this genetic change, the primates' massive jaw muscles shrank, making possible a threefold expansion of the brain.

The exact reasons why these mutations causing weakness were retained in early humans are matters for speculation. But: could we fix these mutations and turn our various muscle genes back to the legacy forms which are still present in chimps and orangutans? Chimps are not crazy bulky muscly either. Their muscles are just better.

It is not just about the muscle. Too strong a muscle and it would tear itself loose from the bony mooring, but that does not happen to the chimps - although I worry our tendons and ligaments are weaker also and so more likely to tear than those of chimps. Or maybe the chimps never really put forth that kind of effort.

A realistic mutation leading to (reverting to) increased strength could let a human with the slim build of Taylor Swift have the strength of a chimp - roughly double to triple the strength she would otherwise have. Chimp Taylor would be surprisingly strong but I do not think she would be stronger than the strongest humans who are actually bulky muscly. If regular Taylor can bench press 100 lbs., Chimp Taylor could bench 300 lbs.

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    $\begingroup$ Overall a great post, but I disagree with "their muscles are just better." Stronger, yes. But they are severely lacking in endurance and fine motor control when compared to humans. It's like comparing a weight-lifter to a marathon runner. Not better, just built for a different purpose. $\endgroup$
    – Michael W.
    Feb 6, 2018 at 19:11
  • $\begingroup$ Thank you Will for answering. I also read that this trade off between human and chimp musculature reduces fine motor control and would make the person less graceful. While nature is good at opting for survival I cannot imagine that the way things are is the apex design allowable by physics. I wonder if one can still squeeze out a bit more power without sacrificing fine motor control. $\endgroup$
    – Eso Di
    Feb 6, 2018 at 19:15
  • $\begingroup$ @Eso Di - do you think chimps have worse fine motor control than humans? I am not sure that is so. $\endgroup$
    – Willk
    Feb 6, 2018 at 20:19
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    $\begingroup$ @Will It's generally a pro-human talking point whenever I read of the differences between humans and chimps or other apes. Here is a small abstract from a paper that discusses Chimps having inferior fine motor control. The strength of great apes and the speed of humans. $\endgroup$
    – Eso Di
    Feb 6, 2018 at 20:46
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    $\begingroup$ Note also that the muscle attachment points for other creatures are different. Similarly-sized apes can out-lift humans quite easily, but even a human child can throw a rock faster and more accurately than an ape because our arm muscle attachments are built for speed over leverage. $\endgroup$
    – Perkins
    Feb 6, 2018 at 22:59

It depends on how crazy your genetic engineering can get and what tradeoffs you're willing to accept. If your genetic engineering is extremely good (or if the aliens started from a different point) then the chemistry used to build terrestrial muscles is definitely not the best option. There are other ways to build contracting fibers that did not arise naturally on our planet but may have on a different world or may have been designed by a sufficiently advanced genetic engineer. The same applies to bone structure. Life on earth generally uses calcium compounds for shells and bones, but there's no reason for that to be universally true. A different species from another world might use something else. Iron bones aren't out of the realm of possibility (although something that extreme would definitely make for a noticeable increase in weight over the human norm.) For a fully engineered creature, carbon-fiber bones could definitely be a thing.

And then there's the actual construction. Arms and legs are basically sets of levers. In a human the attachment points of our arm and leg muscles are relatively close to the joint compared to many other animals. This costs us maximum strength, but lets us move our limbs more quickly for the amount of muscle we have so we are very good at throwing things. Even with entirely normal human muscles, moving the attachment points as little as an inch would make your creature considerably stronger than a typical human of similar size, and only a detailed examination would reveal the difference. She wouldn't be able to pitch at a major-league baseball game with any success though.

  • $\begingroup$ Thank you for answering Perkins. I do like the idea of different construction materials, given the highly advanced nature of the genetic engineering present in the setting, but am uncertain that metal or carbon fiber would be viable given the organic nature of these super soldiers. They are still grown in wombs (both natural and artificial wombs) from infancy, still undergo childhood to reach adulthood, so I am unsure if the they can deviate too far from human biology. They are human-based though so I would like to augment human biology rather than starting entirely from scratch. $\endgroup$
    – Eso Di
    Feb 7, 2018 at 8:00
  • $\begingroup$ Also, while I do like the idea of strength by moving the leverage points of the human arm, I do not want to sacrifice the super human's ability to throw. They would not seem very super soldier-like if they could not pitch a ball better than human athletes. I do like the idea though, and may use that factoid in the development of other humanoid species. $\endgroup$
    – Eso Di
    Feb 7, 2018 at 8:02
  • $\begingroup$ Calcium is a metal. There are organisms on our planet which manipulate iron at a chemical level. Make the cells that lay down calcium in our bones lay down iron instead and you'll get iron bones. (With otherwise human metabolism you'll need some additional reserve of calcium as we use it for other purposes as well.) Carbon fiber would definitely take a good engineer, but it could also be extruded by cells. The tricky part would be the coordination to weave and glue those strands together, but where you're growing them artificially you could provide external cues to coordinate the system. $\endgroup$
    – Perkins
    Feb 7, 2018 at 18:56
  • $\begingroup$ And all that's assuming you want them to mostly assemble themselves for some reason. There's no reason with sufficiently advanced gentech and fabrication capabilities that it couldn't be some kind of amalgam of organics and tech. Perhaps the bones are surgically replaced at the same time that the armored ribcage is installed. Self-reproduction isn't necessarily a design goal, especially where those in charge of the program probably don't want them going feral and then returning to conquer their planet. So organics for brains and power source and replace the other bits as needed. $\endgroup$
    – Perkins
    Feb 7, 2018 at 19:01
  • $\begingroup$ Which also brings up the question of why the soldier is female since male or (preferably) sexless frees up more space and metabolic overhead for things like redundant organs and biological weapons systems. Unless the original plan was to have them reproduce in the field to replace losses, in which case this character is probably a dedicated "mother" type who can produce any of the other types at will given sufficient resources. $\endgroup$
    – Perkins
    Feb 7, 2018 at 19:11

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