The parents of 13-year-old Sam Johnson from Woodbridge say they are "incredibly proud" as he runs 70km in seven days to raise money for a Motor Neurone Disease charity. 

Sam has received donations from Rugby World Cup winner Phil Vickery and former England player Roger Uttley - with Kevin Sinfield also sending him a video of support.

Sam will be running a series of10km runs around both Woodbridge School and Woodbridge Rugby Club throughout the week, finishing on Thursday. 

A rugby player himself, Sam decided to take on the challenge after being inspired by Rugby League legend Kevin Sinfield's "ultra 7 in 7".

East Anglian Daily Times: Sam Johnson decided to take on the challenge after being inspired by Rugby League legend Kevin SinfieldSam Johnson decided to take on the challenge after being inspired by Rugby League legend Kevin Sinfield (Image: Contributed) 

He also made the decision in light of the recent death of Doddie Weir, who passed away from MND at the age of 52. 

Speaking on his JustGiving page, Sam said: "I will be raising money for the Motor Neurone Disease Assocation as many rugby league and rugby union players seem to be affected by this cruel disease. 

"If anyone wants to join me on any of my 10km runs, you are more than welcome.

"Many people, not just rugby players, have been affected by this disease and there is no cure at the moment.

East Anglian Daily Times: Sam Johnson has been joined by friends and family during his challengeSam Johnson has been joined by friends and family during his challenge (Image: Contributed)

"Kevin Sinfield challenged himself and I want to the do the same."

At the time of writing, he has raised £3,582 - smashing his initial target of £500.

Speaking on his challenge, Sam's father, Oliver Johnson, said: "We are incredibly proud of Sam for coming up with this challenge, and for taking it on.

"It's not for the faint-hearted. His mum and I are struggling and we are taking it in turns to run with him each day.

East Anglian Daily Times: Sam's dad, Oliver, said he was incredibly proudSam's dad, Oliver, said he was incredibly proud (Image: Clarke & Simpson)

"He has had wonderful support from his family, friends and the wider community - which is he is very grateful for. 

"It is lovely that some of his friends, and even some of his teachers, have run with him. 

"Sam's target was £500, but with the power of social media has now exceeded £3,500. 

"That is a really meaningful amount."

To donate, visit Sam's JustGiving page here.