The former Leeds Rhinos star raised over $1 million for the MND Association and Leeds Hospitals Charity, in a challenge inspired by former teammate Rob Burrow, who was diagnosed with MND in 2019.
The money will partly go towards a new care facility that will be built in Burrow’s name.
“The support along the route has been incredible right from the start. It was certainly a battle. We wanted a battle and we certainly got one,” Sinfield told the BBC after crossing the finish line.
“I’m broken. I don’t know when I’ll be able to run again.
“Rob knows how much we love and care about him. For those really dark moments, you have to think of Rob.”
‘Benefit every sufferer’
Sinfield, 41, started his mammoth feat at Welford Road Stadium — home to the Leicester Tigers, where he now coaches — on Monday and finished in Headingley Stadium, Leeds, 24 hours later.
His run was split into seven kilometer (roughly 4.35 miles) chunks which he had to complete in under an hour.
Sinfield had initially set a $133,000 (£100,000) fund raising target but the scale of donations rocketed as he completed the run.
Burrow and his family were waiting at the finish line and the pair embraced after a weary and emotional Sinfield crossed the line.
Burrow was diagnosed with the degenerative condition in December 2019, two years after retiring from the game.
MND may have robbed him of his ability to speak and move, but Burrows’ spirit has served as an inspiration for Sinfield to raise money and awareness in his name.
In 2020, Sinfield raised over $3 million after running seven marathons in seven days.
“Today is an amazing day for the whole community and will benefit every sufferer,” Burrow said on Tuesday.
“To my amazing friend Kev, you don’t realize the impact you have had on me and the whole MND community.”