It’s been doing HIIT since long before anyone knew what HIIT was, and as well as improving your cardiovascular fitness and burning a tonne of calories in a very short space of time, it improves your coordination, strength, and, for a lot of people, the amount of confidence you carry yourself with. London in particular has seen a flurry of boxing gyms popping up in the last few years, and also boasts some of the most historic and revered boxing institutions in the country and even the world. But while it draws on the heritage of boxing in Britain and London’s East End, it twists it and zhuzhes it up for those of us who want to get a great workout but with instructors and a really lovely studio.