In the first installment of Middleton's new The Daily Telegraph column, "Sport and Social," the party planner wrote about her year of attending boxing classes at the Fitzroy Lodge Amateur Boxing Club in south London.
She said she started taking the classes to build endurance in her arms for a cross-country ski race in Sweden she signed up for in 2012.
"Our coach is unrelentingly tough on us all during our pad work in the ring where we jab, hook, punch and attempt an uppercut and duck," Middleton wrote. "It's an hour and a half of pure but pleasing agony and by the end I'm broken, worn out and worn down, but I leave on a high, hiding the sweat patches under my hoodie, delighted to have found muscles and fitness I never knew existed."
"One of the biggest pluses of boxing for women – given a tremendous boost by Nicola Adams's Olympic gold last year – is undoubtedly the prospect of a better body and the chance to crunch up to 600 calories an hour toning up arms, bums and tums, and banishing bingo wings, back fat and booze blubber," she wrote. "But boxing's appeal for me is broader than that. Many boxing clubs have a community role and Fitzroy Lodge is no glam-gig, but a thriving non-profit-making charitable establishment: shabby outside and in, but a hub that engenders discipline, self-control and motivation in all who attend."