More fitness myths busted

New exercises invented every week. New gurus trending by the day. Fresh studies to contradict previous findings.

But the science never gets old.

Haven't had enough of the biggest myth busters in fitness from last week? Arm yourself with a few more facts and enter the gym with confidence.

This one has been popularised by modern fitness gurus, who will (fairly sensibly) point out that weight is not a true measure of progress, as fluctuations in the amount of water being retained can lead to day-to-day shifts in the numbers, and putting on muscle can lead to the numbers going up while you are making progress in the right direction.

This does not mean you should toss away your scales entirely.

"Yes, you have to understand that short-term fluctuations are inevitable and don't represent changes in body fat," says Emma Storey-Gordon, the trainer-owner of ESG Fitness. "But, over time, changes in scale weight are predictive of body fat.

"Even if you are also building muscle, the rate at which you can lose fat will be much quicker than the rate at which you can build muscle."

Do not become over-reliant on them, but scales can show whether you are moving in the right direction.

While we all lived in the offline wilderness, the myth persisted that you could, for instance, target the fat around your midriff by doing hundreds of sit-ups.

That myth has been mostly wiped by the ubiquity of the Internet, but replaced by the more subtle half-truth that it's possible to single out problem areas by thinking hormonally: that since, for instance, the stress hormone cortisol causes belly-fat buildup, a bit more sleep and a few sessions on the Calm app should see your abs emerge.

While this is technically, sort of, true, deliberately messing with your hormones is tougher than advertised and not really advisable.

"The truth is, we all have stubborn fat areas that seem to take the longest to get lean," says Storey-Gordon. "There are various reasons for this - hormones and sex both play a role, for instance. These can't be easily changed, so you can't really choose where you lose fat from.

"Don't give up, though. Stubborn areas will get leaner alongside everything else. Patience is the key."

CrossFit and endless neon-tinted, EDM-soundtracked fitness classes have made "rest" a four-letter word in the fitness industry, but constant movement for the sake of it could actually be hindering your gains, not helping them.

"For most people - especially beginners - periods of recovery between sets or intervals allows for higher-intensity, better-quality movement, lower risk of injury and a greater training stimulus that is likely to lead to superior results," says the performance and wellbeing coach George Anderson.

Or, in other words: if you push yourself for an hour straight, you will be forced to lift lower weights, go slower and generally put in less work than you might with some strategic downtime. And the optimum varies - for fat loss, anywhere from 15 to 60 seconds between sets is ideal, but for strength you might spend five minutes preparing for ultra-intense efforts.

Do not worry about time - any exercise is better than nothing.

Once, the four-minute Tabata - 20 seconds of work and 10 seconds of rest, repeated eight times - seemed the logical endpoint of the workout-shortening craze, with claims that it could replace much longer training sessions while offering roughly the same benefits.

Now it seems almost glacial, with three, two, and one-minute workouts promising to harness high-intensity interval training's (HIIT) mystical powers and leave you more time for Candy Crush.

The truth?

Anything is better than nothing, and it is certainly possible to make some gains in whatever limited time you have, but longer workouts have effects that no micro-workout can mimic.

Oh, and by the way: in the original Tabata study, the test subjects - who were professional cyclists - worked so intensely that some of them refused to countenance trying the protocol again.

If you are not doing that, there is no guarantee it will work as advertised.

Is running better than lifting for longevity? Do you need the mobility yoga offers more than a really jacked set of quads? Is Zumba just a waste of valuable time that you could spend boxercising?

"Whatever training style you experiment with, you'll find someone ready to argue that everything else is useless and stupid, that you should stick with them or go home," says Dr Michael Banna.

"This kind of absolutism risks deflating people by telling them that their efforts have been pointless. The reality is, any physical activity has health benefits; the right type is the one that doesn't injure you, make you sad or make you want to stop."

Ideally your physical activity should include a mixture of cardio, resistance and mobility work spread across the week - but do what you enjoy.

THE GUARDIAN