Swing time: experts weigh in on TikTok's kettlebell challenge

The Guardian

10-06-2025

We've all seen the headlines around the importance of strength training. But if you're not a regular gym goer, it can feel intimidating to know where to begin. What is the difference between sets and reps? How many should you do? What if you don't want to turn into the Hulk?
The latest viral fitness trend of doing 100 kettlebell swings a day for 30 days might seem like a straightforward way in. TikTokers' videos showing them doing the challenge seem to have struck a chord, racking up millions of views, and promising the regime can flatten your stomach, make your glutes stronger and help with back pain.
But experts warn people – especially beginners – to treat the trend with caution. While they encourage people of all ages to start strength training, for some, doing 100 kettlebell swings a day might be an 'injury waiting to happen'.
Kettlebell training has been shown to increase muscle mass, which makes your bones stronger, and has been shown in some cases to help reduce fat mass as well as improve back and neck pain, Dr Kim Way, an exercise physiologist and lecturer at Deakin University, says. However, those studies have not assessed doing 100 kettlebell swings a day – typically they have examined some form of kettlebell exercises two to three times a week, Way said.
'There's certainly a lot of difference in … the amount of stress that's being placed on the body, in terms of exercising every day versus having some recovery to allow for the body to essentially adapt,' Way said.
A/Prof Justin Keogh, an exercise scientist at Bond University, said the health benefits also depended on the weight of kettlebell used. A heavier weight will help increase strength, muscle power and mass, while doing more repetitions with fewer rest periods will improve strength and endurance, may reduce body fat, and can have cardiovascular health benefits, he said.
Kettlebell swings can be advantageous because you have to coordinate different upper and lower body segments and it mirrors the movement patterns that are 'more similar to what life throws at us,' Keogh said.
Doing 100 kettlebell swings a day carries the risk of 'going a little bit too hard, too early', Keogh says. 'The chance that your hamstrings, lower back, forearms, etc, are going to feel really tight the next three or four days … is pretty high, and then you might not want to do any exercise over those next couple of days.'
Keogh encourages people to start strength training carefully and gradually intensify their workouts in order to minimise their chance of what's known as delayed onset muscle soreness, which occurs when muscles that haven't been used to the level of exertion get quite sore for several days post-exercise.
Way also agrees 100 kettlebell swings is 'quite a lot of swinging', especially if done every day. 'What I see with trends like this is that you're getting people excited about an exercise, which is great … but exposing people, especially if they haven't had any exposure to an exercise, that's just an injury waiting to happen because you haven't had the time to allow your body to adapt to the muscle stress, and the joint stress, that potentially this exercise will be placing on the system,' they said.
Way is also concerned people might not be developing the correct technique. 'While the kettlebell swing might not necessarily look like a super complex movement – and compared to other exercises, it might not be – but even if you've just got a little part that's a bit wrong, it can put yourself into an area of potential injury.'
They encourage people to find resources to ensure that they're using the correct technique. Way also advises if a person is new to exercise, they should listen to their body because if they start to fatigue, 'this is where technique can really quickly break down' and make injury more likely.
Our genes largely determine the maximum size and strength of our bones, which is what's called 'peak bone mass', but exercise can also influence whether we reach our full bone mass potential by the age of 25-30. People generally begin to lose bone mass from the age of around 40 onwards. Keogh says it's better to begin resistance training earlier because then your muscle and bone mass will reach a higher peak. 'But again, we do know that regardless of the age that you start resistance training, you will get benefits compared to those people who [aren't].'
Way says that types of exercise like yoga and pilates, which require us to use our body weight as a form of resistance, are 'a great way' to get into resistance training. However, people should keep in mind that if they use body weight exercises for their main form of resistance training there probably is a 'ceiling effect' once you are strong with your own body weight. Then using external weights – whether at the gym or finding weights at home through using cans of food or filling backpacks – can be helpful to get some resistance.
Way emphasises 'it doesn't need to be a lot' – sometimes the big fear people have is that to do weight training they have to emulate bodybuilders online who are training for two or three hours each time.
'It actually can be pretty simple,' Way said. You can just strip it down, allocating five to eight exercises targeting your main muscle groups (your chest muscles, back muscles and leg muscles), and doing two to three sets, anywhere between eight and 15 repetitions.
'When you're trying to get into exercise, the best form of movement is always going to be the one that you enjoy. Resistance training or weight training is definitely a great one, because it gives you a really big host of benefits,' Way says.
Natasha May is Guardian Australia's health reporter
Antiviral is a fortnightly column that interrogates the evidence behind the health headlines and factchecks popular wellness claims
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