(CNN) It's the moment athletes the world over dream of: Stepping onto the podium at an Olympic Games as the national anthem plays, and feeling the weight of a gold medal hung around their neck.

The thought of being able to drape themselves in their country's flag at the end of a race well run, to bask in the cheers and applause of their delighted compatriots, is what makes the years of training worthwhile.

But for some, the tune that plays is unfamiliar, the flag that is raised not the one they were born under. These are the men and women who have abandoned their homes in the hope of securing sporting stardom elsewhere.

When Ruth Jebet took gold in the women's 3000m steeplechase at the Rio Olympics, after racing to victory in 8:59:75 -- just shy of a world record -- she was greeted with boos in her native Kenya -- because she was running on behalf of Bahrain.

Jebet opted to run for Bahrain three years ago.

Many in Kenya accused Jebet, 19, of betraying her homeland.