Or more accurately, he's swimming in a genetic pool of his own. Phelps has a number of fortuitous physical endowments that have enabled him to dominate like no other. Simply put, he is the perfect swimmer.



Here's what Phelps has going for him:

• Most people have a wingspan that matches their height. Not Phelps. He may be 6'4" tall, but his arms extend outward to a total of 6'7".
• The average shoe size for a person the size of Phelps is 12; he wears a size 14 which gives him a 10% advantage over the competition.
  
• He also has a larger than average hand size which allows him to move more water.
  
• Phelps is double-jointed in the chest area; this enables him to extend his arms higher above his head and pull down at an angle that increases his efficiency through the water by as much as 20%; this also allows him to have quicker starts and turns.
• He has proportionately short legs relative to his long, powerful trunk; this large upper body is the engine that powers his long arms. Moreover, his unique physique reduces drag through the water and allows for maximum propulsion.
• Phelps has a greater-than-average lung capacity allowing him to execute his underwater dolphin kicks longer than the competition.
• He has a genetic advantage that cause his muscles to produce 50% less lactic acid than other athletes. This means he can work at higher work loads for longer periods.
  
• With a low body fat of 4%, he is better able to convert his effort into speed.
  

Looking at this list it's as if Phelps was designed to swim.

Which leads to an interesting question: Given the potential for genetic modification and gene doping, should it be acceptable for other athletes to acquire the same physiological endowments through artificial means?

If not, what makes it so acceptable to come by these traits 'naturally?' And how could the genetic lottery ever be construed as something that's not arbitrary and unfair?

Read more about Phelps's extraordinary physiology here and here.