The high altitude body type.

[zerodish]

I'm one of those people you see tossing telephone poles at the highland games. Having high altitude genes or growing up at high altitude changes your body. Basically you will need a longer top tube. Along with this the high altituder will be a bit heavier. This is just the opposite of bicycles designed for women. I use 4 strategies to cope with this. First of all you need to find a bicycle with as close to a stand over height as possible. If you need say a 24 inch frame using the old 10 speed standard and all you can find is a 23 inch frame then this will result in a top tube that is 1 inch shorter than an already too short top tube. Different manufacturers have different standards for frame sizes so try to find one in a shop to try to find out what the stand over height is. Second  buy a bicycle designed for fat tires and use skinny tires. The smallest tire I can use with out getting pinch flats is a 35mm or a 1 3/8 inch tire. As a practical matter 38mm or 1.5 inch tire is easier to find. This lowers the top tube by 8mm or 1/3 inch. Third try to find a bicycle with a sloping top tube. This type of frame will need a longer seat tube and possibly one with a larger diameter. Shaq broke a seat tube just by sitting on it is a bicycle shop. My current Specialized Hardrock uses a 1 1/4 seat tube which is just what I would have designed in a steel frame. After this you will need to add a longer stem. 150mm is usually the longest standard stem. Mine is 145 mm chrome molly and I transferred it from my old frame after 100000 miles. Of course the best solution is for manufactures to realize this and design frames with short regular and long top tubes. The top tubes and down tubes will need to have a larger diameter. 21 inch frames are twice as stiff as 25 inch frames which is just the opposite of what it should be. One study which I will post as soon as I find it found larger frames which were designed to be stiffer were less stiff than smaller frames. Flimsy frames shimmy. My Cannondale touring frame did this even unloaded.   I don't expect this to happen any time soon. Half the worlds population lives within an hours drive of an ocean. Before I went out and cycled 100000 miles loaded down I had a considerable amount of money in the bank. I passed up the Americano the BLT the Atlantis the Nomad the Long Haul Trucker the Safari any thing made of aluminum and several custom builders because the frames were not strong enough and stiff enough for me.

[canalligators]

There's probably some truth to the genes thing, but it seems like a lot of very specific proscriptions based on one factor.  What are the intermediate parts of the mechanics?  I mean, why does the altitude gene or upbringing indicate stepover height or top tube length?  Is it because your torso is longer or you need more/less space for lung function?  Does reach of the extremities determine something, like blood circulation?  Does it affect cycling at low altitudes or just at high?

Other factors come into play.  Wouldn't I just acclimate to high altitude?  Or low for that matter?  What if a person has syndromes that affect joints and muscles, like Marfam?  Or diabetes, or blood pressure, or obesity, or your history of exercise and diet?

Sorry, too many variables to blame it all on one factor.  It almost sounds like you read some faddish book, or research that hasn't gone very far.  No disrespect meant, I just don't buy it.

[zerodish]

The high altitude body type is not optimized for bicycling at least not at sea level. I have short legs and a long upper body. The correct size for me would be a bicycle with the seat tube of a  24 inch frame and the top tube of a 26 inch frame. Any such frame with a 1 1/8 inch down tube is going to shimmy even when not loaded. You can only do so much with a longer stem. I spent 40 years of my life at 6 feet and 205 pounds. The medical charts tell me I am on the edge of being over weight. If I had normal proportions I would weigh 185 pounds. Upper body simply weighs more than legs. Since medical charts have not caught up with this reality I don't expect bicycle manufacturers to do so. High altitudes tend to be colder and people who live in cold climates tend to be bigger. This is not the case along the equator. There is a need for frames with seat tubes of a 21 inch bicycle and top tubes of a 23 inch bicycle. I have nothing but respect for people like Terry who design frames for women or people like Zinn who design frames for the very tall. I am advocating for 10 percent of a neglected minority.