Olympic legend Michael Johnson recovering after 'mini-stroke'

Johnson, 50, wrote on twitter that he had a Transient Ischemic Attack, but was back at home and hoping to make a full recovery.

He added: "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 American won four Olympic golds over 200 and 400m between 1992 and 2000, and held the world record at both distances.

Since retiring he has forged a successful career as an expert for the BBC's athletics coverage and is widely seen as one of sport's most authoritative TV experts.

His announcement provoked a wave of support from the athletics community.