Originally Posted by jur
Read the
MAPP site for aging athletes. There you will get all the info you need. Like eg muscle mass only begins to decrease at 60, not 40. The only thing found to decrease steadily with age is max HR. This seems to be THE reason older athletes can't compete against younger ones, not muscle ability.
I've read the MAPP and it has some great information about human physiology, as well as sport specific information. Good read if you like that sort of information.
To the OP, genetics plays a large role in your ability to compete at a high level. Unfortunately, at this time, we must live with the genes that we inherited from our parents. But, not all is lost. The appropriate training regimen will maximize the expression of the genes that you possess, allowing you to compete at "X" level, if that is what you are interested in doing.