A group from Littlehampton is in the middle of an ultimate endurance challenge with 4th Musketeer and Compassion UK.
The Muskathlon works in partnership with churches in developing countries to empower vulnerable children living in poverty.
Austin and Michelle Wade, Steve Case, Stew Smith and Richard Knowles, known as Cookie, from Arun Community Church set off last week to start the Muskathlon in Rwanda on Friday.
Unlike any other event involving running or cycling, Muskathlon offers first-hand exposure to the good work of organisations in Rwanda while raising significant funds for Compassion UK, a charity working there.
Richard, 53, a support worker from East Preston, has already raised £3,000 for the charity and has seen seven children sponsored by friends and family.
He said: “I think the highlight of the trip will definitely be meeting my three sponsored children and letting them know how important they are to us.
“It has been the thought of them going to school and having access proper nutrition and medical care that has kept me training in the wet and cold.
“I think the hardest part physically will the last hour of the marathon. I did the London Marathon back in 2002 and can still vividly remember the pain of those last four miles. It was agony and I’m expecting this to be significantly harder given the temperature, altitude and hilly terrain.
“The altitude and hills are likely to be my biggest problem as all my training has been at sea level along the coast between Littlehampton and Worthing.”
The money raised will go towards a child survival project that provides vulnerable mums with mentoring, child birth assistance, check-ups and immunisations.
Richard was keen to improve his fitness and needed a challenge to help him focus. His is passionate about giving children and young people the best possible start in life, so when he found out four of his friends from church were booked to go to Rwanda for the Muskathlon, he decided to join them.
Darren Allwright, Compassion UK Muskathlon ambassador, said: “In the lead up the trip, the focus is on training and physical condition but by the end of the week, you realise that you are part of something much greater.
“The funds you raise make a monumental difference to the lives of children living in poverty. It’s a unique opportunity for ordinary people to take part in a life-changing and extraordinary event.”