There are a couple of tactics that you can use, but one of the best ways to search Twitter for Athletes in your area is with Twitter Advanced Search.
You can define the location, search for specific text in the tweets, as well as look for hashtags that are unique to your search.
Here are a few highlights on the Advance Twitter Search Options:
- You can search All Words, Any Words, Exact Phrases, or even searches to include "none of your selected words or phrases"
- Location: Defaults to 15 miles, but you can change this after your first search
- Hashtag Searches: Boolean search any terms you want
Location: Houston, TX
Hastags: #triathlon OR 5k OR 10k
Check out Twitter Advanced Search