Kettlebells have been heavily en vogue for quite some time now. But what actually are they good for and are they really good at it?
What Are Kettlebells?
Kettlebells are cast-iron weights that basically have the shape of a cannon ball with a handle on top and, as far as I know, they first appeared in 19th century Russia.
Maybe at that time Russians had a lot of leftover cannon balls that they decided had to be good for something else. Or Russian kettles are made to last forever and instead of using them as ersatz ammunition someone thought they might also make a very fine piece of workout equipment.
Seriously, using kettlebells simply means taking a different route in working out when compared to the western world of strength training, that is dominated by putting something heavy and flat onto something long and cylindrical. Where the dumbbell and barbell mostly call for slow and controlled movements, the kettlebell wants you to go dynamic. It’s no coincidence that its basic movements are called “swing,” “snatch” and “clean and jerk.”
Are They Safe?
Let’s now look at a video of one of the kettlebell movements mentioned above, the kettlebell swing:
No doubt this recruits a lot of muscles, as practically the entire body is used to stabilize against the weight pulling away from it.
But this, in my opinion, also is the biggest problem with kettlebell training: you work against a centrifugal force. Your muscles are trying to pull in one direction, the kettlebell in the other, and your joints are stuck in the middle. How the same exercise instructors who tell their students to not swing a dumbbell to avoid precisely that can go on to tell them it’s perfectly ok if they do it with a kettlebell, is beyond me.
The next problem is much more insidious, as the health risks it can create only become apparent after a long time. And when they happen, it’s too late. Consider this video of a woman showing her kettlebell improvement and especially how she does the exercise at about 1:45:
Can you spot it? Yes, she rounds and straightens her spine to get the weight up. A typical mistake made by kettlebell beginners, which can lead to the same backpain I a long while ago talked about in this video on beginners doing squats.
Are They Effective?
Given the way they are used, kettlebells basically are a mixture of strength training and cardio. Which according to what I read, is also one of their main selling points: do it all at once and get a great workout in less time. But when looking at research done on the outcome of kettlebell training, we get what can probably be expected of a training that is a little bit of this and a little bit of that.
One Danish study, for example, found that in previously untrained persons kettlebell training improved muscular strength, but had no effect on cardiovascular health (PDF). A study at the California State University compared traditional strength training to kettlebell training and found that traditional weightlifting led to a greater increase in strength.
Well, what should we make of this? It is rather safe to say that you should take the sensationalist claims kettlebell training is sometimes advertised with with a grain of salt. Kettlebells are still fairly new in the western world, and that makes them exciting to many people, but “new” doesn’t always automatically equal better.
If you are a beginner, you are most likely to benefit from kettlebell workouts, because they engage your entire body and train endurance and strength but, on the other hand, as a beginner you are also more likely to injure yourself with them.
Experienced endurance or strength athletes have, at least in theory, ligaments that should be able to withstand the centrifugal forces better. But they are well-advised to focus on their primary sport and do that with intensity. There is a reason, after all, why world class marathon runners also aren’t world class weightlifters.
If you want to try kettlebells out, of course, go ahead. But I’d say do them carefully, keep an eye on how your body reacts to this form of training and what influence it has on your workout efforts in general.
Picture courtesy of Kevin Teague.