The Human Speed Limit?

Question
Hi, and thanks in advance for any insight you can give me on this topic. I am doing a research paper about running, and my question for you is - what do you think the human speed limit is? Do you think a man will ever break the 3-minute-mile barrier? How far can the human body take us naturally? Are we close to our speed capacity already?

Thanks for any information you can give me.

Answer
Alison,
I do not know that a 3 minute mile is possible, however it was once thought impossible to run a 4 minute mile.  There are mega marathoners that can run for nearly 300 miles in grueling conditions.  Is this human?  There are some people whose bodies allow them to do phenomenal things.  There may be someone that can run a 3 minute mile (that would be 45 second quarters, which is realistic anaerobically).  There may be ways to train that will be more effective.  People are training earlier and harder.  There was a college sprinter that broke Michael Johnson's 400 record.  This is unheard of in track and field.  I predict that we will continue to see speed improve.  It will not be remarkable improvements, but steady.  The body is an incredible machine.  The more that we learn and find out the more incredible it seems.  I hope that this helps.  Best of luck.
Ryan