Paralympic long jumper Markus Rehm has pulled out of August's Rio Olympics after failing to prove that his prosthetic leg does not give an unfair advantage.
The 27-year-old won Paralympic gold in 2012 and was hoping to become the second athlete with a prosthesis after Oscar Pistorius to compete at the Olympics.
To become eligible for the Olympics, Rehm had to prove that his prosthesis gives him no advantage over other athletes, but a study he commissioned on the issue was inconclusive.
The German will now work with athletics' governing body on a rule change allowing athletes to compete in London next year after what the IAAF described as "extremely constructive and positive" talks with general secretary Jean Gracia.
Rehm still intends to make the Paralympics and hopes to be eligible for the 2017 World Championships.
