LOS ANGELES • In his heyday, no one could catch up with four-time Olympic champion Michael Johnson on the track, but the American will have to draw on his famed powers of recovery after revealing that he was recovering from a mini stroke.

The former world record-holder in the 200m and 400m said on Twitter on Saturday that he had suffered the medical problem, but the prognosis was good and a full recovery is expected.

"Last week, I rather surprisingly suffered what's known as a Transient Ischemic Attack (TIA) or mini stroke," the 50-year-old tweeted.

"It seems these things can affect anyone, even the once fastest man in the world! I'm no stranger to a good exercise plan and have thrown myself into it with my usual focus and determination."

"The good news is I'm back at home with my family, cleared of any issues and have already made great progress on my road to a full recovery."

Johnson became the first man to win both the 200m and 400m at the 1996 Atlanta Olympics and then captured gold in the 400m four years later in Sydney.

His 200m world record of 19.32sec stood for 12 years until 2008, when it was broken by Jamaican sprint great Usain Bolt with a time of 19.30sec.

Arguably one of the greatest sprinters of all-time, Johnson's 400m world record of 43.18sec stood for 17 years until South African Wayde van Niekerk lowered it to 43.03sec at the 2016 Rio Olympics.

According to Britain's National Health Service, a mini stroke is caused by a temporary disruption in the blood supply, resulting in a lack of oxygen to part of the brain.

Symptoms can include speech and visual disturbance, and numbness or weakness in the face, arms and legs, with the effects often lasting for a few minutes to hours.

A mini stroke can often be followed by more and is usually a warning sign that a full stroke can occur in the near future.

REUTERS