I don’t like spending much time on single exercises unless they are awesome for helping athletes get better or get back to their sport after injury. The kettlebell swing is one of those enigmas whose value we are starting to see in the real world. I wish I could summarize this article into “it helps” or “it’s a waste of time,” but the kettlebell swing is one of those exercises just good enough to talk about but not clear enough in practice and in research to show undisputed value.The kettlebell swing is one of those exercises just good enough to talk about but not clear enough in practice and in research to show undisputed value, says @spikesonly. Click To Tweet
Unlike the squat or other movements, the kettlebell swing has very little research to show efficacy in training, mainly due to the fact it’s hard to load in a way that is truly progressive. In this blog post, I review the need-to-know information and cover the available science. It’s likely this article will not persuade you to change your mind if you lean toward one side or the other, but if you are on the fence, you will likely step off and find a place for the exercise in some way.
The Kettlebell Swing Science
Just to be fair, I will include any evidence that shows positive changes to a subject, even if the subject is a recreational volunteer. Athletes tend to have really good training ages, but some athletes who are not big fans of the weight room may not have a very established training age. Be warned, just because an athlete has a poor training age in the weight room doesn’t mean they are not athletic or prepared. An athlete who has played sports for years decelerates their body and produces high outputs in games and in practices, so we can’t view them as a sedentary or low-fitness examples.
In this review, I cover the five needs of coaches: keeping athletes fit, big, strong, fast, and resilient to injury. Ironically enough, the swing has some risk associated with it, like any exercise, but in all fairness, so do most typical lifts. Therefore, for the sake of this argument, I will say that the exercise is perfectly safe to perform under supervision, and I will only focus on the adaptations or possible benefits from acute experimentation. Very few intervention studies are available, but we don’t need perfect research to make sound conclusions.
One point that I can’t spend too much time on is the discussion regarding type of swing. Those who train with kettlebells understand that swing type, or the mechanics of the swing, plays a role in how the exercise affects the body. However, I don’t think it will make such a huge difference that we can scoff at the results of the research and say the swing type is the reason it didn’t work if the outcome is poor. I do think it’s fair to give some warning when acute electromyography profiling is done, but for other areas like hypertrophy and conditioning, I am hard-pressed to agree that the style is that dramatic that it leads to cardiometabolic responses to the body or hypertrophy to the legs.
Kettlebell Swings for Sprinting Speed
The most important study is sprinting performance, but there is very little available, likely due to smart researchers knowing that it’s unlikely that kettlebell swings are secret speed weapons. Trust coaches to know from trial and error if a solution works, as they have been experimenting due to the force of competition for decades. Based on available information, acute swings and a regimen incorporating them do help general populations. The first study looking at potentiation did hint that the population may not have the ability to create enough of a stimulation due to loading, but with recreational athletes, those are the realities. The second study on recreational populations showed no training benefit over eight weeks, so to me it’s just not potent enough to rely on as a training tool.I don’t think kettlebell swings will ever show up as a speed tool no matter how heavy or how skillfully athletes do them in training, says @spikesonly. Click To Tweet
Of course, you can say that it didn’t include elite athletes, but if a population that is more untapped and more likely to respond to training doesn’t get better, I find it harder to believe that an athlete who is more advanced will somehow be able to unlock “advanced” benefits. True, technique matters, but if it requires so much precision to do, then the results need to be impressive with a follow-up study showing motion capture and speed testing. In summary, I don’t think swings will ever show up as a speed tool no matter how heavy or how skillfully athletes do them in training.
Kettlebell Swings for Jumping Power
The next argument is that using kettlebells for jumping power or explosive strength requires a bit of experience. While I agree with the outcomes and the experimental design by Lake and company, I don’t agree that the population involved can be extrapolated to serious scholastic or elite athletes. You don’t need to be an Olympian, but 20- to 24-centimeter jumping heights are not transferable to serious training ages. It’s not that the swings do nothing, it just means that responders tend to be those who take training seriously or are involved with a program that needs to get serious.
Video 1. Athletes can use various forms and styles of kettlebell swings for training. So far, we don’t know much about how the different techniques help or hinder athletic development.
The 10-minute continuous swing study from the Air Force included 40-yard dash and jump training, but the population was nearly six seconds in the 40, so I don’t include it earlier. The results don’t actually conflict with a Scandinavian study on a middle-aged population, which is perfect for me but hardly for athletes. The mean improvement was 1.5 centimeters, something that can come from nearly any intervention.
Finally, most of the studies I see compare controls or workouts that resemble exercise programs for “unfit” populations. When compared to a conventional weightlifting program, kettlebell training provided no benefit to healthy subjects. While the programs looked athletic at first glance, the loads and training background weren’t sufficient to represent a true athletic population.
You can say that both weightlifting movements and kettlebell exercises have no effect on jumping, but to me this simply shows that performance and fitness research belong in separate worlds. I realize that second study by Lake analyzing the ground reaction forces of strength exercises and kettlebell swings was provocative, but force analysis without a tale of the tape and clock (jump performance and speed performance) over time is far more evident of value than descriptions of force and time on a computer screen.
Kettlebell Swings for Hamstring Health
I am not going to cover the risks of injuries with kettlebell swings, but I do know some coaches will make an argument that they are dangerous because there is always a chance of someone getting hurt. The current buzz with swings is that they are alternative forms of power development due to a number on a force plate or activity from an EMG electrode. Three studies that looked at the specifics of muscular recruitment acutely are from the usual “hamstring experts,” and two others are rehabilitation-style investigations. No article demonstrated exciting findings for hamstring and glute recruitment, but I liked that the Australian study evaluated three styles of swings and showed that a good hinge makes a difference.
Video 2. Adding a band theoretically increases the eccentric demand of the exercise. How much the additional equipment adds to decreasing hamstring injuries is unknown, but it’s likely very little.
Based on the findings of the hamstring exercise comparison, it appears that kettlebell swings are better suited for the semitendinosus rather than the biceps femoris. It’s not the end of the world, but each hamstring muscle has specific roles in sport and risk profiles. Collectively, the three hamstrings, along with other muscle groups, create hip extension and deceleration of knee extension during sprinting. The kettlebell swing appears to be a good recruiter of the posterior thigh, but it’s just not special to the point we need it in our training arsenals.The kettlebell swing appears to be a good recruiter of the posterior thigh, but it’s just not special to the point we need it in our training arsenals, says @spikesonly. Click To Tweet
I hate to sound pessimistic, but based on lack of intervention studies and the interpretation of the acute EMG data, there is not enough infrared evidence to demonstrate that kettlebells are potent choices to help soccer teams stay healthy. They do activate the glute and hamstring enough to be part of a program, just not enough to highlight them as singular solutions in injury reduction.
Kettlebell Swings for Hypertrophy
Due to the fact that swings are not upper body demanding, most of the studies focus on lower body and spine activity in acute training. Some studies have done more well-rounded evaluations of the exercises and have included body composition. Like explosive strength, we need to compare what is the baseline we expect to help athletes rather than elderly patients or general populations. What I like about kettlebells is that they are not demanding on the joints, but they are also not exactly spine-friendly, so some strain on the back is expected. In summary, kettlebells for hypertrophy are not great, as power exercises are less about mechanical overload and more about rapid expressions of strength.
You can get some muscular development via kettlebells, but they are not prime options compared to machines and barbells. Personally, I am a barbell person due to the options in overloading for the entire body. The current literature shows subtle changes compared to controls, but due to the population, study design, and magnitude of change, swinging a kettlebell won’t make the changes most practitioners need. So, if you do recreational fitness and want to swing for some general health benefits and get some incidental muscle cross-section, have fun, but you won’t win an Olympia title any time soon.
Kettlebell Swings for Conditioning
Now comes the tricky part—how do you define conditioning? Most people look at conditioning as endurance, so kettlebell swings helping an athlete run faster at the end of a long match isn’t the same as someone trying to be fit for metabolic health. Thus, we don’t see much in the research outside of low-grade evidence that kettlebells can be a great circuit solution, but not an aerobic capacity session outside of Tabata-style intervals. For me, using strength training as the primary means of aerobic capacity or specific repeated sprint ability is a lousy way to train.
Anyway, the main evidence for fitness from kettlebells comes from what we see from Chan, et al. and Thomas, et al., and think about as a hiking replacement, not supramaximal. I can get into VO2 max testing more as an argument to adaptations versus elevating heart rate, but the exchange or similarities are more about adaptation than response. Focusing on how hard an exercise is rather than what training effects it creates is misleading, so think about comparing the modalities.
Video 3. The classic double-arm KB swing can be used for basic conditioning and general preparation. Currently, there is very little evidence that this exercise improves absolute human performance.
Swings are demanding in terms of muscular fatigue, so endurance athletes will likely not benefit from adding them or replacing conventional training. Specificity matters as well, so swinging may increase mitochondrial changes, but running or cycling faster isn’t proven. If you want general fitness, kettlebells are promising; if you want athletic performance conditioning, they’re not appropriate for team or field sports.If you want general fitness, kettlebells are promising; if you want athletic performance conditioning, they’re not appropriate for team or field sports, says @spikesonly. Click To Tweet
I will save you the time and burden of deciphering the research and say this: Nothing in the studies demonstrates that if you do kettlebell swings for the typical 15 minutes or less, you will become the next champion in sport, but you could burn enough calories to become significantly leaner. Conditioning is not just about aerobic fitness, but sometimes reducing body fat. So, in short, like many intense intervals, you can burn a lot of calories. I have seen statements such as one calorie per swing and other similar estimations, but even if that is true, the demand of swinging for 20 minutes is exhausting and may not be congruent to athletes as a main exercise.
Kettlebells for General Preparation and Fitness
I started to like kettlebells after years of just using them for dumbbell replacements. I don’t like to use them for goblet squats—or even like goblet squats much at all—so they always seemed to be great for jump squats and maybe single leg RDLs in the past. I started swinging a bit during the summer and like how they felt for my legs. As someone in their 40s, I like the unloading to the knees, and I felt great after a session rather than worrying about flaring up from a high-impact exercise. Most coaches will share my personal preference, and the majority of the bell curve is usually in the middle.
My recommendation is to use them for circuits and general strength exercises in the off-season and only use them sparingly later. It’s not that I think they are a bad fit for in-season exercises, but I don’t consider Turkish get-ups or kettlebell swings a main exercise for athletes like snatches, squats, and pull-ups are. Feel free to decide what works for you, but after digging in the research more to fully give kettlebells a fighting chance, they seem to be a great fit for general preparation and teaching, not for max speed or hypertrophy of advanced athletes. Kettlebells add a lot of great options in training, and I think it’s worth investing in both education and equipment for athletic development, but not as a specific means to becoming faster or adding a lot of mass to athletes.I recommend using kettlebell swings for circuits and general strength exercises in the off-season and only use them sparingly later, says @spikesonly. Click To Tweet
Swing Away, but Know the Limitations
If you’ve finally reached this conclusion paragraph, you are either looking for a last-minute tip or a recommendation. Well, my feeling is this: If you like doing kettlebell swings and other exercises for fitness, that means it’s a general preparation option. If you train athletes and think kettlebell swings will add slabs of muscle, make athletes faster, and jump out of the gym, it appears the science doesn’t support that wish.
Kettlebells are part of training and add much-needed variety to a general fitness program, but don’t expect them to be the missing ingredient in elite sport. Use swings without fear that they will do something dangerous or cause injury, but don’t treat them like a panacea. Kettlebell swings are fun and have merit, just don’t get carried away with them.
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