How many cardinal sins are you committing with that kettlebell?.

To paraphrase satirical publication The Onion, it’s that time of year when the Earth’s successful completion of an orbit around the sun inspires us to reflect on our fitness regimes. With so much misinformation out there, it can be difficult to know what to do (clue: classic exercises like squats, deadlifts and bench press, tracking your progress) and what not to do (eating and drinking like King Henry VIII). Whether you’re a January “resolutionary”, getting back into the kettlebell swing after a festive lay-off or stuck in a good-intentioned rut, there’s a chance as strong as Mr Eddie Hall that you’re making at least one of these common workout mistakes. No bicep-curling in the squat rack should go without saying, as should never ever blow-drying your nether regions. (We’ve witnessed it, and more than once.)

“Yes, cardio will likely burn more calories during a single session than strength training,” admits Mr Jonathan Dick, a Tier X coach at the Kensington, London, branch of transatlantic health club group Equinox. “However, what strength training will also do – and cardio won’t – is raise your metabolism for up to 36 hours afterwards while your body uses the nutrients that you’ve provided it with to repair your muscles.” Cardio should be a “last resort”, he says, after you’ve exhausted all other variables (but not yourself).

Ego can seduce even experienced gym-goers into trying to lift more weight than they can hoist with strict form. But lurching your way through your reps not only doesn’t count, it also invites injury. “Get used to working the muscles that you should be working and not, say, using your shoulders grossly on a pulling exercise because you want to lift more weight,” says Mr Joe Holder, a New York-based, Nike-endorsed trainer with Messrs Virgil Abloh, Heron Preston and Eugene Tong numbering among his fashionable clientele.

There’s nothing wrong with ambitious targets, but aim for too many at the same time and you won’t hit any. “If you want to get significantly stronger or increase muscle mass, it’s challenging to decrease body fat at the same time,” says Mr Andy Vincent, trainer at London’s Third Space sweatboxes. “Or if you’re training for a distance event and simultaneously trying to bulk up, ultimately you’ll be doing a half job of both.” Rather, Mr Vincent advocates “periodising” your training by dividing it into 12-week, one-goal blocks.

That said, you definitely shouldn’t split your training by body part. “It’s slightly old-school and really the realm of pro bodybuilders,” says Third Space’s Mr Vincent, who mentally faceplants whenever a member tells him that it’s “chest day”. “The average person doesn’t need to train this way. I really wouldn’t split your routine much more than upper/lower body or push/pull, both of which work amazingly for 99.9 per cent of the gym population.” If you’re lifting every other day at most, you can safely work your whole body.

Up there with abdominal crunches – ineffective at best, back-tweaking at worst – as A Bad Move, the upright row involves lifting a barbell to your chin, elbows up and to the sides. “It targets your shoulders, in particular the upper portion of the trapezius muscles in your upper back, which are likely to be overworked anyway – especially if you spend hours hunched over a keyboard,” says Ms Verena Stefanie, a personal trainer at Equinox Kensington, who prefers safer lateral and front raises (where you raise dumbbells to your sides and, er, front).

Not sleeping enough isn’t a mistake that you make in the gym per se. (Nodding off on the leg press is poor etiquette.) But if you have a vitamin ZZZ deficiency, "You’re setting yourself up to perform poorly, in and out of the gym,” says Mr Rob McCabe, also a Tier X coach at Equinox Kensington. Indeed, “regular exercise and excellent nutrition don’t matter” without sufficient shut-eye, which also has a huge effect on body composition. A regular bedtime and alarm will help ensure that your minimum quantity of seven hours is also high quality.

“There's no excuse for going topless in the gym,” insists Mr Alex Shephard, manager at Equinox Kensington. Or barefoot. “I get that you’re going for more stability and awareness, but it's a safety hazard and just kind of gross,” adds Mr Holder. But all the gear won’t help if you have the wrong idea, says Third Space’s Mr Vincent: “Wearing the latest kit and hashtagging a picture of your post-workout shake seems to have become more important than effort, discipline and consistency.” All the gear and the right idea, however…

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