Swimming and Running Efficiency

I know I just posted something, but I had to add this. My officemate, Lucas (who is a really good swimmer from Brazil), is doing one of his class projects on the efficiency of swimming compared to that of running.

He just told me that he found an article stating that the efficiency of running is between 70-80%, meaning anywhere from 20-30% of the energy you expend doesn't do much for you! What is swimming???

5-8%

WHAT?!?!?! That means that over 90% of what you do in the water, is useless! You are just accelerating the water! How frustrating is that???

I guess that explains a lot about the mentality of most swimmers I know.....