Possibly when it features a ‘sick station’ and demands you be ready to die in order to participate, but maybe that’s just us…

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The feeling of triumph and achievement after a tough workout is nigh on incomparable- from soaring endorphins to the sense of satisfaction as you sink your aching limbs into a warm bath, a heavy weights session or long run can elicit very positive feels indeed. Of late though, fitness classes and concepts seem to be becoming all the more hardcore, with punishing circuits designed not just to take you to the point of failure (small muscle tears are actually a good thing in terms of building strength), but modelled so that you do indeed fail to ever complete a workout, sometimes in dramatic fashion, apparently.

One such workout is Flatline, conceived by trainers and ‘leading endurance experts’ for London’s Gymbox and currently only on offer at the brand’s new Farringdon outpost. Marketed as the ‘most dangerous gym class in the world’, Flatline involves partakers loading themselves up with a 12 kg weighted vest before taking on five circuits of rope climbs, kettlebell thrusts, burpees, box jumps...you get the picture. Exercises become ‘increasingly difficult’ as you go along, with ‘sick stations’ (buckets in a corner) provided for when the going gets tough and oxygen masks provided as part of the cool-down.

As if this didn’t sound extreme enough, a compulsory paramedic and cardiologist are on hand throughout in case of medical emergencies.  The promotional video  even features a GP and paramedic warning of the risks of taking part in the class (cardiac arrest for one, apparently) which is the most baffling ‘sell’ I’ve ever encountered, and questionable on a multitude of levels, not least the fact that this is perhaps not the best use of much-needed medical resources. Granted, it’s a PR stunt, but one in poor taste given that the prospect of a heart attack and other health issues are highlighted to promote the class. A cardiac arrest or collapse are possible in any situation in life, and surely working out should enhance your general health instead of putting it at risk. Gambling with your health in order to earn kudos by doing a gym class that no one can finish anyway definitely defeats the ‘strenuous but short’ purpose that the likes of smart, proven to be effective HIIT exercise  promotes, and I’m just going to leave a very gladiators-esque quote here from the Flatline trainer featured in the advert:

“You want a body to die for, you’ve got to be willing to die for it.”

Most health authorities, experts, gyms and trainers big up exercise as a means by which to extend your lifespan, so this is certainly a curveball in the current fitness revolution, and more than likely off-putting for anyone about to embark on a fitness regime, or who just generally doesn’t want to feel like actual death during and after a workout. To be fair to Gymbox, company director David Cooper does underline that this isn’t a class for newbies, and that ‘you should not even think about this class if you are unsure in any way about the ability of your body to be pushed to its absolute maximum physical limits, and probably some way beyond.’

The problem with the ‘pushing beyond the limits’ thing is that this is inevitably where the serious damage happens, and even an onsite medical professional can’t ultimately save you from a heart attack, negate the detrimental effects of a collapse or fix injuries. All of the above are likely to put you out of action for quite some time, and in the case of cardiac issues the prognosis is of course touch and go, which is ironic when the goal of a fitness regime is to enhance strength, stamina and general wellbeing over time. Gymbox claim that Flatline is intended to ‘test’ these elements, but a test without slow and steady, attainable progress isn’t a lot of use to those of us aiming to become fitter for the long haul. If you can’t complete a single class, surely you’re more likely to give up on the whole endeavour altogether, especially because most of us don’t want to spend precious post-workout time vomiting or struggling to breathe through an oxygen mask. Targets and pushing yourself are one thing, but ending a workout looking and feeling like you need a trip to A&E, stat, is quite another. As many professional athletes would agree, it’s just not worth it, and is counterproductive to attaining not only fitness goals, but optimum physical, not to mention mental health. A workout ought to be uplifting, not leave you traumatised.

No one is forcing you to do a backbreaking workout, but if you find yourself in situ the pressure to conform can be overwhelming

Clearly you can take the likes of Flatline with a pinch of salt, pushing the hype to one side and going at your own pace, but being strapped to 12 kg of dead weight is far from a good idea for everyone for starters, and this ‘one size fits all’ approach is part of the problem with extreme, fast paced fitness workouts and challenges. Believing in yourself and making progress is essential in any well thought out fitness plan, but having people shout at you to do something you’ve got serious reservations about is quite another. No one is forcing you to do a backbreaking workout, of course, but if you find yourself in situ the pressure to conform can be overwhelming. As a result, form is often sacrificed in order to ‘keep up’, risking burnout or injury, as orthopaedic surgeon and sports injury specialist Mr. Gorav Datta  highlights in the case of a number of ‘extreme’ workouts.

“Circuit training is generally an excellent cardiovascular and strength workout. My main concern is the loss of technique with fatigue which ultimately, does lead to injuries. I have experienced in particular an alarming number of back injuries from extreme group cross-fit style classes.

“I would say to avoid the temptation to try and lift weights in excess of capability; this has a damaging impact on knees and can ultimately lead to overuse of the cartilage and damage to knee-caps.”

Flatline is a 45 minute class, which Gymbox list as the longest possible duration for a class of such intensity, but if you’re doing HIIT right, sticking to the principles of short yet efficient intervals of exercise is key to reap the benefits, as Mr Datta explains:

“HIIT is an excellent cardiovascular workout, and an efficient way to work out by shortening work-out lengths and potentially reducing repetitive strain on muscles and joints, for which you will reap the benefits longer-term.”

“That being said, don’t be tempted to extend the duration of a HIIT workout too quickly; the exercise is determined by short, sharp bursts of action, and lengthening the session places over exertion on the heart.”

As for individual exercises during demanding workout sessions, being aware of your own body, posture and form is key, as in group settings a trainer may not notice when you’re performing a move incorrectly, and the emphasis to push hard can override self-awareness. Mr. Datta has a few tips for common killer moves, that when done well glean maximum results, but when performed in a state of exhaustion tend to trigger issues:


“Burpees are an excellent cardio workout and great for both the core and lower limbs. They are physically very demanding so there is real danger here that the technique goes once you get tired, which can lead to harmful back strains.”

“I know it can be very difficult once the body becomes physically tired, or you’re reaching the end of a workout, but it’s really important to try and keep your back straight at all times.”

Squats and lunges

“Squats and lunges are good exercises to develop the quad muscles. However, be cautious about going too deep into the squat; this puts extra stress on the front of the knee. Poor form with weights can also lead to back and knee injuries; a common issue I see in particular is patients with patello-femoral knee issues (kneecap pain) with patients doing too many deep squats with heavy weights, and also hip impingement.”

“Of utmost importance here is not to bend the knees too much, 90 degrees at the hip and knee is the correct amount to bend.”

Martial arts style moves

“MAA is a strong, safe way to work out, under the eye of a responsible trainer who can spot and correct technique errors. There is a lot of kicking involved in this work out, so ensure good stretching before to minimise the risk of muscle strains. Over-stretching of the hip during high kicks is a common problem which occurs, and it is crucial that you exercise sufficiently in advance to loosen and stretch the muscles surrounding the hip joints.”

“High kicks can lead to hip problems, so it’s crucial to kick well within your height limits.”

The takeaway message? Work hard, hone your technique, rest-up and don’t get taken in by the bravado and one-upmanship of ‘impossible’ workouts. Healthy competition is all well and good, beating yourself up literally and figuratively is not. There’s a balanced middle ground in this health and wellbeing business, and there’s not a sick bucket in sight.

Want to get to grips with HIIT?  Here’s the bottom line on quick, results-driven workouts…

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