Hope some one can help, I’m writing researching for a story on a fictional character who has incredible cycling performance…ie non human type sort of 10 w\kg FTP
What biological changes do you scientifically might make this achievable? or even relatively believable,
I went with two hearts as it’s a nice metaphor etc
Over to you thanks in advance
Bitten by a worm at Birth and now has worm blood as a result.
Fed only with tainted meat on a carnivore diet since birth.
It’s fiction, so you can hand wave at least some things.
One thing you might play up for humor is that they will need a lot of food, and I mean an inhuman amount when compared to TDF riders. Because right now, I think their FTPs may be in the mid 6 to low 7 W/kg range.
some things to consider, heart is just the pump, vascularity is important both muscular and lungs, 2 hearts 4 lungs or lungs 2x as large, thus now you need space inside a body for all of that which has a detrimental impact of the individuals A in the equation CDA. It is a fun thought experiment, but you probably also need more haemoglobin to carry the oxygen and probably more blood volume. Of course to fuel this you need lots of energy so lots of extra mitochondria, highly efficient digestive system, and lots of food intake. part of that extra vascularity would also be to release all of the heat from the extra energy burnt to achieve that high power output.
This could be a really fun thought experiment for someone with a real depth of knowledge in physiology and sport science.
I’d look here as a starting point:
Stan Lee's Superhumans - Wikipedia.
When I saw this thread, I remembered an episode of a man with massive strength despite not having large muscles. If I remember correctly, they were able to measure and see in his muscles that he activated more motor units than the average person.
I didn’t watch many of them, but these abilities, if fictionalised further, may be a nice bridge between the natural and supernatural in terms of story and imaginative possibilities for both the writer and reader.
According to many sources Inigo San Milan style Z2 training is the answer you are looking for
You should check out the Sports Gene by David Espstein. I seem to recall a story about a cross country skiier that had some genetic defect that made him a gold medal endurance athlete. It’s nothing as sensational though as two hearts.
This guy:
Strong Asthma
The protagonist could produce hyperhemoglobin. Hemoglobin is made up of four subunits (two alpha, two beta), each of which contains one iron and binds an oxygen, so if hyperhemoglobin contained six subunits (two alpha, two beta, two gamma) then 50% more oxygen could be carried in the blood. Everyone would want to blood dope from him so he’d be on the run from pharmaceutical companies trying to imprison him in a secret lab.
I first read that as taint meat. Which could be the source of some kind of super power.
His abdomen is a second pair of lungs, so he cannot digest anything and need to drink some special liquid
You don’t need to go to two hearts to get superhuman performance, just equal some of the capabilities of animals. A very well trained human might have a VO2 max of 80 mL/(kg min), the link below says a well trained dog can have a VO2 max of 240 (3x as high).
As was already pointed out, food needs will be high, I just realized that my 50 pound dog eats enough for a human more than twice that weight.
Another option is better lungs, a bird like flow through lung is much more efficient that the bellow system used my mammals
Not sure on where the superhuman abilities should come from, but make it a female cyclist with a 10 w/kg FTP and you potentially have more controversy to cover in the novel…
What’s the genre of this story? The suggestions in this thread are all over the place.
Is this a comedy, a drama, sci fi, mockumentary? High brow or low brow? The New Yorker or The Onion?
Much too logical of a question.
Next, you’ll be asking to see the creative brief.
Ha! Just trying to feel out if the viagra jokes have a place in this thread or not.
Super human testosterone, epo production & muscles that don’t fatigue.
Some great and funny ha ha 
suggestions here.
The short story version is a Kafkaesque fictional biography titled ‘the flea with two hearts and the Kaiser’ it’s an allegory of David vs Goliath but on a Sisyphean mountain. So it’s largely classical and meant for general readership, so two hearts is understandable.
A book idea I have; will use only pre industrial genetic selection technology over tens of thousands of years, the long road but an interesting society.
Thanks for all your input
You could also look at insects for inspiration. For instance fleas can jump up to 66 times their body length.