You can use these to find related blogs and forums on Google.

inurl:forum intitle:sports
inurl:blog intitle:sports

i know few popular blogs you must go search there best blog comments
Skysports
The Sports Network
NBC SPORTS
Bleacherreport

Do a Google search for "Best Sports blogs" and you will surely find several people who have put up lists of them.

Hi ASD,

I'd add, when you find these blogs, write 4-5 paragraph, in-depth, detailed comments designed not to get links, but to build friendships with top bloggers.

People have a funny way of avoiding even well-written comments, when the focus is not on building bonds, but on getting traffic or links.

Comment to give, not to get, and you will see sweet benefits.

Make friends with those sports bloggers. Tap into the power of having a huge network of buddies in your corner.

Ryan