Click here for a definition of the idiom.
Student or Learner
"I've been there or thereabouts for four or five years. I've had medals at world and Olympic level but obviously gold is great. But to us this is a team sport and winning all three is superb for us.' as well as some of the following quotes."
What would "there or thereabouts" mean here?
not a teacher
Just to expand on the definition in Rover's link.
In a sports context the phrase "there or thereabouts" usually means at or near the top of that particular sport. In your example the athlete is saying that he or she has been performing well and winning medals, although not necessarily winning gold.
For another example, at the beginning of a football season a commentator might say that Manchester United are expected to be there or thereabouts this season, depending on how well they avoid injuries to key players. Meaning the club will probably be at or near the top of the league.
From The Independent: "You can argue Wenger is a failure, but Arsenal are there or thereabouts each season."