Bailey Matthews from Doncaster, South Yorkshire was cheered as he crossed the finishing line at the triathlon event at Castle Howard.
Matthews sped up as he saw the end was in sight and looked happily at the crowds who were cheering him on.
Just before he crossed the line, he abandoned his walking device and reached the finishing line unaided. Cue a huge cheer.
BBC North Yorkshire shared the video on Facebook, which has already received more than 187,000 likes and 125,000 shares within 23 hours.