Prior to the Google Penguin and Panda search engine algorithm updates, exact match domains could rank relatively easily with enough content. While the plural "track pants" would be preferable, for those familiar with track and field, the domain Trackpant.Com could serve as a bendable to sell track gear - not just pants. However, the main brands - Puma, Nike, Adidas, UnderArmour, etc which sell this type of gear already have their own brandable domains. It is the kind of domain you might use to set up your own affiliate website but it would likely be difficult to sell to companies which already have their own brand or would view this domain as limiting. Fyi I compete a few times a year in Masters level track and field events primarily 100 and 200 meters.