Kettlebell Research: What Science Says

Kettlebells have enjoyed growing popularity as a full-body training tool for improving cardiovascular health and musculoskeletal fitness. Yet for all the enthusiasm among personal trainers, experimental research on the effects of KB training was scant until last year, when studies began showing up in peer-reviewed journals. Here are the recent research findings on KB training.

Study 1. Metabolic Demand of Kettlebell Training

Hulsey, C.R., et al. 2012. Comparison of kettlebell swings and treadmill running at equivalent rating of perceived exertion values. Journal of Strength and Conditioning Research, 26 (5), 1203–07.

Experimental question. The two-handed KB swing is generally viewed as a foundational training approach for KB training. Researchers wanted to determine whether performing continuous KB swings would create an energy cost capable of improving cardiorespiratory fitness. To find out, they compared the metabolic demand of KB swings to treadmill running at equivalent ratings of perceived exertion (that is, subjective assessments of exercise intensity).

Subjects. Thirteen subjects (11 male, 2 female, average age = 21.4, average height = 69 inches, average weight = 170 pounds, average BMI = 23.5) volunteered for the study. All were deemed moderately trained and had no KB experience. Prior to testing, a certified KB instructor familiarized them with the two-handed KB swing exercise.

Study procedures. In the first experimental trial, subjects performed 10 minutes of two-handed KB swings, alternating 35-second swing bouts with 25 seconds of rest. The men used a 16-kilogram KB, and the women an 8 kg KB. Subjects were encouraged to maintain a steady swing count averaging 22–25 per minute. A certified KB instructor gave continuous feedback, helping subjects maintain correct swing execution and posture.

After 48 hours of rest, study participants returned to the testing lab and completed a 10-minute treadmill run at a subjective intensity (RPE of 15.3–15.5 on a 6–20 scale) equivalent to what they experienced during the KB swing trial. An automated metabolic gas analysis system commonly used in exercise studies measured oxygen consumption and kilocalorie expenditure. The final 7 minutes of each work bout were used for data analysis.

Results and discussion. Table 1 compares key cardiovascular and metabolic values obtained in this investigation. At an equivalent subjective RPE, subjects had no significant difference in heart rate. Oxygen consumption and calorie expenditure were significantly higher for treadmill running than they were for KB swings. However, it should be noted that subjects completed both 10-minute exercise bouts at above 85% of their age-predicted maximum heart rate. Thus, KB swings, albeit for just 10 minutes in this investigation, did elicit a physiological response necessary for improving cardiorespiratory fitness.

The study did not determine an optimal KB workout duration or a weekly frequency necessary to obtain a meaningful improvement in cardiorespiratory fitness; further research is needed to answer those questions. However, the kilocalorie expenditure (375 kcal) obtained from this study suggests that KB training is a viable exercise option for inclusion in a weight loss program.

To read additional studies, please see “Kettlebell Research Update” in the online IDEA Library or in the January 2013 issue of IDEA Fitness Journal.

For the latest research, statistics, sample classes, and more, "Like" IDEA on Facebook here.

Len Kravitz, PhD

IDEA Author/Presenter
Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University ... more less
February 2013

© 2013 by IDEA Health & Fitness Inc. All rights reserved. Reproduction without permission is strictly prohibited.

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Article Comments

Michael Pardo
On Feb 05, 2013
not to mention that kettlebell training will elicit muscle growth, while most cardio training does not. Also, at 512 calories burned on the treadmill I'm assuming 30-45 min. duration. So cardio burned 11-17 calories per minute and kettlebells burned 37.5 calories per minute. Looks to me like ketttlebells are the winner here.
Anonymous
On Feb 05, 2013
I have not invested in kettlebells yet and have just dumb bells instead. I would like to see if there is any research that shows why I should invest in something I can pretty much do most exercises done with KB with DB instead. That is the study I want. I already knew that the kind of training mentioned here is better use of my time than a treadmill.
Bridget Cox
On Feb 06, 2013
Both the treadmill and kettlebell tests were 10 minutes in duration. So actually the average rate of calorie burn was 51.2 calories/minute for the treadmill and 37.5 calories/minute for the kettlebell exercise. I think what would have been interesting to observe is the EPOC response between these two exercises.
Anonymous
On Feb 07, 2013
You could perform circuit strength training using safer exercises performed properly (lifting under strict control rather than swinging) and get the same cardiovascular and strength benefits far more safely.
Aaron Thomas
On Feb 07, 2013
I don't see how these are tests are related, as they are preformed under different conditions. RPE doesn't really matter if there is no control between experiments. Kettlebell is more of an interval where treadmill is constant. I'm not suprised that the treadmill burned more calories because the rate was constant. Had the rate been constant for kettlebell swings I think there would've been more simalarities.
Joe Horton
On Feb 07, 2013
Please help me understand the numbers. 51.2 calories per minute running and 37.5 per min. kbell swinging?! That's 3072 cals. per hour running and 2250 for swinging! I recall rowing on an indoor erg all out for 500 meters and achieving 1500 cals. per hour rate. Is there something I'm missing with those running and swinging rates? I can see the 17.1 and 12.5 cal. per min. rate, times 10 minutes, equals 171 and 125 calories burned for the 10 minute performance. Thanks for your time.
William Bannister
On Feb 07, 2013
I'm not a runner, but 512 kcal in 10 minutes sounds way high, especially for the RPE cited. A quick search turned up a "runnersworld.uk" site that estimates a 170-lb person running a 7-minute pace for 10 minutes burns around 180 kcal...that sounds more like it. Here's the link:
http://www.runnersworld.co.uk/weight-loss/how-many-calories-do-you-burn/...
Anonymous
On Feb 07, 2013
Perhaps you should have done the study with lighter kettlebells (5 -10lbs) and kept the group moving for the same amount of time they were running. THis would have been a direct comparison and I am intersted in that result!!
John Penley
On Feb 07, 2013
Interesting study however they are totally different energy systems where the kettlebell is an anaerobic system and running is a aerobic system even thought it was only ten minutes. The subjects had a mean average of 21.5 years in age that means that estimated HR for that 220-21.5yrs=198.5 bpm and their average HR in perfomance was 177-180 this is in the 90% of Submaximal HR so what is more important is the type of calorie burned. According to the ACSM and affliates they are burning Protien calories for only 10min. So depending on the type of calorie response we are looking for it may be a predictor, however when we usually discuss calories in the level of training it is usally for prediction of necessary consumption levels for premier athletes. So all that it was a nice comparision it is highly improbable that we could use if for constant predictions. I the other side it is usefull to know if your client/patient in training in this realm and you are responsible for thier nutritional plan.
Anonymous
On Feb 07, 2013
Too many variables... They may not have used kettlebells before but they may have used the treadmill at some point, thus making the body adapt differently. Most importantly, did they feel pain on their knees because of running? Did they feel any pain on the shoulders or back because of the kettlebells? You will always burn more calories when you are not used to a certain program. My main concern is the injury you get from certain types of training
Anonymous
On Feb 07, 2013
There is no doubt that exerting energy by using a kettlebell burns a lot of calories and builds muscle mass, however, I would like to see more research on injuries from kettlebell use, specifically back and shoulder injuries. I have a hard time believing that flinging a heavy object like that is safe and controlled.
Erik Petersen
On Feb 07, 2013
How can anyone perform a true kettlebell swing at that slow of a rate? Answer......you can't! Rubbish! And the weights, please. My 50 something ladies swing a minimum weight of 20 kg and some swing the 32 kg for a duration similar to what is posted in the article. And that is after their main strength portion of the workout! See for yourself (if your swing rate is slower than about 32 rpm or higher than 40 then you are not performing a true kettlebell swing). Most will land between 35-40.
Anonymous
On Feb 07, 2013
I think some of you are missing the point of the test. The test question was to determine "whether performing continuous KB swings would create an energy cost capable of improving cardiorespiratory fitness". It's not denying the ability of kettlebell exercises to elicit muscle growth and it's not saying it is a cardio exercise, it is just questioning as to whether it might be an exercise to improve cardio fitness.

It also mentioned in the question that these were "subjective assessments" of participants and that is is an experimental trial. Maybe the fact that the response was not as high as treadmill runners, they might be convinced to do another trial with a higher swing rate or kettlebell weight or add in some other controls.
Anonymous
On Feb 07, 2013
So many variables come into the equation for this kind of testing. Body weight in constant motion while running vs. dead weight being swung w/ momentum while there is a pause in motion at top & bottum. I would say its more efficient to burn calories on the treadmill.
Anonymous
On Feb 08, 2013
Sure, my markers would stay low if I swung a 16kg for ten minutes straight let alone in almost 1:1 intervals. The same would go for my female students with an 8kg... They would laugh in my face if I asked them to swing a bell like this.

Also, does the author mean there is not much research on the effects of kettlebell training or there is not much research on the effects of kettlebell training that still allows us to make a case for the treadmill and chronic cardio...? It doesn't take more than a few minutes on google to see just how ridiculous that statement is.
Terry Crissman
On Feb 08, 2013
I've worked out on the treadmill as well as with a KB. Listen, the KB always leaves me with a oxygen debt much higher than the treadmill. I teach burst training and I use the KB. Believe me when one of my lady clients have worked 30 seconds swinging a 10lb KB at a high rate of speed they have a much higher oxygen debt than those who are on the treadmill. The whole idea is to use 100% of your maximum effort. If you preform anaerobic exercises at 100% maximum effort the results will always be better than a boring treadmill.
Anonymous
On Feb 08, 2013
Concerned that Kettleballs can put excessive strain on the wrist . . . any news about that?
Erik Petersen
On Feb 08, 2013
More people will complain of wrist pain doing push-ups than kettlebell swings. But, you know, what about knee strain when running, eye strain and carpal tunnel working at the computer! Wrist strain????? Only if you are taught by "experts" in kettlebell technique like those that conducted this silly study:)
Susan Retzlaff
On Feb 10, 2013
In response to the concern over the wrists during KB use...if the wrists on kept in neutral position, which is good form, there shouldn't be strain. I also have to agree with the comment above about more strain to the wrists doing push-ups.
Brad Elliott
On Mar 24, 2013
Interesting study. I've been using KB's for a few years now and have been teaching them for the last year or so. The thing that sticks out to me here is the weight involved. Although these are typical weights for strict beginners, I would consider these fairly light for intermediate users and maybe should have been bumped up about halfway through the experiment.
Existential Angst
On Aug 03, 2013
All well and good, but the real Q is:

What improvement do kettlebells offer over the cheaper/simpler dumbbell?

Answer: None.

In fact, with few or no exceptions, dumbbells offer a much more efficacious workout.

Bottom line is, a weight is a weight.
And a kettlebell is merely a clumsy weight.
Jennifer Knye
On Sep 22, 2013
I wonder if the participants rested in intervals during the treadmill test or did they just go for the entire 10 minutes. This would suggest to me that the results would be different if they had performed the swings with no rest albeit probably to difficult for someone with little training.

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