An 83-year-old man was one of many adventurous runners who took on the Mudpack Challenge for St Francis Hospice at Ashridge Estate in Berkhamsted.
Competitors choose between a 7km or 14km challenge, and then slide, climb and run a muddy assault course consisting of more than 30 obstacles.
Local personal trainer Paul Stevens, who spent two weeks creating the course for the hospice, expressed his amazement at 83-year-old Brian’s achievement.
He said: “I spotted a green swimming hat approaching the final section of the course. I noticed straightaway that the participant was showing great determination and agility as he bounded and scaled the obstacles.
“His name was Brian, and he’s 83 years old. If I have half the levels of fitness, determination, agility, strength, and mindset as Brian when I am just 63 – let alone 83 – I’ll be a very happy man.”
There was also a first for the event as couple Danielle and Jeremy got engaged at the finish lane.
More than 500 runners took part and raised more than £60,000 for the hospice.