The first triple amputee to survive the Afghanistan war shows his enduring strength despite the injuries by lifting more than 100kg.
The dad of three is training for a 1,000-metre swim on May 28 and hopes to raise over £400,000 for veterans charity REORG.
Mark, who lost both legs and his right arm after stepping on a bomb in 2007, said: “I’m working really hard on this next challenge.
“Obviously swimming with only one arm and no legs is very different. I’ve got my work cut out.”
Mark – who now works as a motivational speaker and consultant – took part in the 2017 Invictus Games, where he met Prince Harry and won two silver and two bronze medals.
The following year, Mark took home a total of seven medals – including four golds – and was awarded an MBE for services to the Royal Marines and Veterans in 2020.
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In 2016 the brave war hero told the Sunday People : “The Taliban did me a favour because it set my life on a path I could never have dreamed of.
“Back in the beginning when I lost my limbs and almost my life, I wanted to die. I wanted someone to put a gun to my head to put me out of my misery.
“I would have sold my soul to return to the man I was before the explosion – but today I can honestly say I wouldn’t want to change a single thing about my life even if I had the chance.”
After leaving the Royal Marines in July 2010, he ran 3,530 miles across America on his prosthetic blades to raise money for military charities.
Then in 2011 Mark, who already had daughter Kezia from a previous relationship, became a dad again with the arrival of son Mason.
In 2012 he was an Olympic torch bearer and he also got a hero’s welcome when he pedalled home to Plymouth after a 3,000-mile UK charity trek with three pals.
Then in 2013, he and Becky became parents again with the arrival of baby Evelyn.
Mark, who has also done skydiving, abseiling, bungee jumping and even climbed Ben Nevis, said: “Of all my achievements, it is my family I am most proud of.”