Move up a gear: fitness studios in the capital have introduced a range of high-impact shorter classes (Picture: Getty Images) Getty Images

Today’s extreme workouts are all about burning the maximum number of calories in the minimum time, says Peta Bee – Evening Standard.

Oneupmanship at the gym was once about how long you had stayed on the treadmill, how many entire lunch hours (and more) you could swallow up with a single workout. That seems a lifetime ago. As the fitness industry revved up its thinking and our heads were turned by the science, we became more economical with exercise. First, high-intensity interval training (HIIT) took hold and we began to realise we could get more from doing less, but now the entire industry has seemingly been turbo-charged.

Classes have downsized to the bare minimum, preferring to push you for maximum burn. Group bike workouts that once lured in the body- conscious with two-hour interval sessions are now being repackaged as turbo classes that can be neatly slotted into your lunch hour; marathon-style training runs have shrunk to snack-sized 20-minute interval sessions on the treadmill. We now boast not about how much time we spend at the gym, but how little.

It could hardly be better news for the cash-rich, time-poor, who are no longer plagued with guilt about their lack of commitment. And the trend has spurned an interest in data- tracking and its endless opportunities to impress by burning the maximum number with the minimum effort.

In Pursuit cycle sessions at Equinox gym in Kensington (equinox.com), instructors purposely shift the focus from gut-busting effort to metrics, wattage and distance to appeal to the new breed of number-crunchers.

It’s all about your RPMs and your mileage, and the more ferocious the calorie-burn in these super-short sessions, the bigger the badge of honour afterwards: a four-minute session at Fitness First (fitnessfirst.co.uk) can gobble up 13.5 calories a minute; interval-based sessions up to 250 calories in a quarter of an hour. Not surprising, then, that there’s evidence of the trend for abbreviated fitness cropping up everywhere.

Gyms such as Frame (moveyourframe.com) in Shoreditch, which offers a lengthy menu of workouts lasting 30 minutes, each requiring exertion of the highest order, and Good Vibes (goodvibesfitness.co.uk), where you can add to the intensity of a 25- minute session with a Power Plate, were among the first to squeeze workouts to good effect.

Now personal trainers are selling themselves on the claim that their results are fast in every sense of the word, and emporiums such as The Library in Notting Hill (thelibrarygym.com), Educogym (educogym.com) and Rev5 (rev5.co.uk) — a newly launched high-intensity weight-training studio (the first one is open in Windsor and more are to follow) — boast results from just 15- minute sessions.

“There’s a lot going on when you work intensely for a short period,” says Educogym founder Jamie Myerscough, the man responsible for whittling away Robbie Williams’s body fat and transforming golfer Darren Clarke. “And you can really boost the metabolism further by adding resistance exercise and weights that will push your system to its limits in a short time span.”

At Core Collective (core-collective.co.uk), the boutique one-stop fitness shop in Holland Park, the most popular class is Velocity — a 45- minute sprint through interval- training, core-stability exercises and flexibility work which, says head trainer James Pisano, leaves you wondering why you ever spent hours doing multiple workouts in the name of leanness. “People now realise that the beauty of combining and condensing your sessions is that you gain in terms of fat-burning,” Pisano says. “Even in a short 10-minute session you will increase your VO2 max, your maximum oxygen consumption, and make huge fitness gains as long as the exercise is of a high enough intensity.”

In Grid, a range of 30-minute classes at Virgin Active (virginactive.co.uk) to be rolled out this year, participants move across a gridded floor space using six primal movements — twisting, pulling, lifting, bending, squatting and lunging or jumping and leaping over obstacles — and burning up to 900 calories an hour. “What you’re looking for is to drive up levels of hormones that accelerate fat-burning,” says Zana Morris of The Library. “And the only way to do this is to work your whole body really hard.”

Professor John Brewer, head of sport and applied science at St Mary’s University, Twickenham, says the science behind the latest convenience workouts is sound. “We know from studies on athletes and sedentary people that when you ramp up the intensity of exercise it quickly raises the metabolic rate, often to levels that can be 15 to 20 times higher than at rest,” says Brewer. “This elevation of fat-burning continues after youve stopped — your body will become a more efficient user of excess energy if the exercise equation and intensity is right.”

If you are looking for rapid changes to your physique, then long and slow is not the way to go. For the past few years, Brewer says, the fitness industry had lulled people into a false sense of security, thinking any level of physical exercise would burn fat fast. “But a gentle cycle or jog might use 250 calories an hour — small fry to what you get if you work harder,” he adds. “Thankfully, more people are now aware that you need to work harder for quicker results. It works.”

Read the article here: http://www.standard.co.uk/lifestyle/health/where-to-get-a-high-intensity-workout-in-london-10401049.html