The sports space is certainly crowded, but the size of the market creates plenty of opportunity. This is not a zero sum game.

The key to differentiation in a crowded space, is focusing on what it is that makes your product/brand unique? Do you have a story that is compelling? Has your product increased strength by X%, or saved lives, or fill a specific need within an interesting space.

Some great new products to review, that have entered into the space recently would be:

http://rocktape.com/
http://www.evoshield.com/
http://www.vibramfivefingers.com/index.htm

What you'll see, is that they have crafted their brand message to get to the core of the user experience. Find your story - one that resonates with your target users. Then tell it loudly!