Kettlebell Research: What Science Says

by Len Kravitz, PhD on Feb 04, 2013

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.

IDEA Fit Tips , Volume 11, Issue 2

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

About the Author

Len Kravitz, PhD

Len Kravitz, PhD IDEA Author/Presenter

Len Kravitz, PhD, is the program coordinator of exercise science and a researcher at the University of New Mexico in Albuquerque, where he recently won the Outstanding Teacher of the Year award. Len w...

22 Comments

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  • Jennifer Knye

    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.
    Commented Sep 23, 2013
  • Existential Angst

    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.
    Commented Aug 03, 2013
  • Brad Elliott

    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.
    Commented Mar 24, 2013
  • Susan Retzlaff

    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.
    Commented Feb 10, 2013
  • Erik Petersen

    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:)
    Commented Feb 08, 2013
  • User

    Concerned that Kettleballs can put excessive strain on the wrist . . . any news about that?
    Commented Feb 08, 2013
  • Terry Crissman

    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.
    Commented Feb 08, 2013
  • User

    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.
    Commented Feb 08, 2013
  • User

    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.
    Commented Feb 08, 2013
  • User

    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.
    Commented Feb 08, 2013
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