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Can Kettlebells & Ultimate Sandbags REALLY Make You Strong?

kettlebell training

That is something a lot of people might be implying, okay, not implying just flat out saying! Heck, the other day on my Instagram someone responded to a series of videos of me demonstrating how to use kettlebells for rotational training by saying, “kettlebells don’t make you strong, barbells do!” Now, I wouldn’t typically make a blog post about an outrageous comment unless I felt that this was actually a pretty strong sentiment. What kettlebells and Ultimate Sandbags suffer from is that their outward load is much less than that of the barbell. Sadly, that causes many to miss out on how these great tools can make one really strong!



Coach Boyle and many other successful coaches have evolved by changing their view points as more information becomes available and we start to think BIGGER about strength.

Because kettlebells have more of the research, for now, I am going to reference a lot of the kettlebell research in this post. There are several ways that Ultimate Sandbags have the crossover but do different things as well (a post for a later time;)

I have seen kettlebells go from a training implement very few knew anything about, to seeing them in Walmart, Home Goods, the most random places. With the popularity of kettlebells being so strong, it may seem odd to question their value. However, as most things go, when something becomes popular and mainstream, there is a bit of backlash.

Surprisingly some of the biggest advocates of kettlebell training and some strength coaches are giving confusing messages about the true validity of kettlebells. That led me to look and think about, “are kettlebells really a way to get strong?”

So, what has the science said? Well, to say it has been compelling isn’t really the case. Not because of the kettlebell or the drills, but because of how these studies were performed. The way we look at conclusions of studies and not the bigger picture could make kettlebells look as though they aren’t a very valuable tool. A closer look may actually show that kettlebells are even MORE powerful than we may have given them credit.

What has the research TRIED to show us? Well in one study by Otto et al. (1), the effectiveness of kettlebell training versus weightlifting was put to the test. The impact of these two forms of training were measured by vertical jump performance, strength, and body composition.

The results? Both showed improvements, but weightlifting was showed to be far more effective especially in performance of the back squat and power clean. Get rid of those kettlebells right?! Well, not so fast!

In the study, researchers compared the use of a 16kg kettlebell to that of loads of 106kg (35 pounds vs. 232 pounds for our metric challenged friends) used by the weightlifting group. Now I am one of the first to say that weight is not all equal, but even THIS is a bit much. Why weren’t two 48kg kettlebells used instead? I mean that would have been still 10kg (around 22 pounds) lighter and I think would have been a much more interesting comparison.

Imagine what could be found with even a more challenging load of 32kg for more trained males rather than the 16kg weight that is used as a great baseline of kettlebell training. This is where I am always confused by coaches saying tools are tools and weight is weight. If this is true, how come the same amount of weight used wasn’t even close!

Having personally seen how kettlebells and Ultimate Sandbags kept me from being on disability and transforming my life, yea, I think they make you strong!

Closer weights might have reproduced similar results that were seen in a study by Gullet et al (2) compared front squat to back squats. The researchers concluded, “The front squat was as effective as the back squat in terms of overall muscle recruitment, with significantly less compressive forces and extensor moments.” Hmmm, wonder if we would have seen the same with heavier kettlebell front squats as the load sits a bit differently and I would like to venture to say we would see some interestingly different results!

Another study by Lake and Lauder (3) is also very intriguing. The study compared jump squats with kettlebell swings to measure maximal and explosive strength. The researchers found that kettlebell swings improved maximal strength and explosive strength similar to that of the jump squats. Okay, who cares? Does this mean we need kettlebells if we can use jump squats?

Two big issues to contemplate here. One is again, the weight of the kettlebells were 12 and 16kg. It would be very interesting to see how different kettlebell loads would cause different outcomes.

More importantly may not be the forces we see in the body creating, but those the body are absorbing. Soviet Sports Science expert, Dr. Michael Yessis, states that plyometric training can cause forces acting upon the body to 20 times one’s own bodyweight (4). Therefore, with those that may not have the joint integrity, health history, or really know how, may find kettlebell swings to be a much safer alternative to jump squats with very similar results.

There is research to show how kettlebell training has been helpful in improving posture, VO2max, and even bench pressing. So, is the question really are kettlebells effective (5, 6, 7)? I think the challenge many are facing is really the question, “are kettlebells better?”

One of the HUGE advantages that kettlebells and Ultimate Sandbags have is the ability to train the other planes of motion. The barbell is a sagittal plane tool (unless you get into dangerous movements with it) and that means we miss A LOT of our strength training for real world with it. These tools don’t compete, but actually compliment one another!

That is why I hear a confusing message by some kettlebell advocates that in the end the barbell is better because you can apply more load. Hmmm, that would make some sense, yet, we would have to put that line of thinking under a bit more scrutiny.

We saw in an earlier study that a HUGE discrepancy in load can make for an unfair comparison. Yet, the question still looms, if I can go heavier with the barbell isn’t that better for my training?

Very simply, no! What most people usually misunderstand with barbell training is that the weight sits in almost always the most stable position, is performed from the most stable stances, and the implement itself is very stable and balanced. So?

A study by Saeterbakken et. al (8) tested both unstable objects and body positions for muscle activity in the shoulder (dumbbells vs barbells and seated vs. standing). It was concluded by the researchers that, “the exercise with the greatest stability requirement (standing and dumbbells) demonstrated the highest neuromuscular activity of the deltoid muscles, although this was the exercise with the lowest 1-RM strength.”

Combine this study with the front vs back squat study and we start to notice a few important factors that are often missed in developing really GOOD strength training programs.

1. Weight is a factor, just not the only factor.
2. How weight is applied to the body (holding position) is a very important variable.
3. The stability of the implement itself can alter the amount of neuromuscular activity.

14 years ago doing double 97 pound kettlebell clean and jerks shows that if we use the right weight, building strength is never really a concern. 

How does this relate to kettlebell training? Well, I would argue that the weight of the kettlebell isn’t a limiting issue. I have never seen people routinely throw around double 48kg bells. Instead of trying to compare the kettlebell to barbell lifts, why don’t we use the unique attributes of kettlebells to create more effective lifts.

For example, there are plenty of people that could deadlift double 48kg kettlebells. How about changing the body position to more staggered or single leg? How about applying a kettlebell on one side, both sides, or uneven weights during less stable body positions? This would not challenge strength? Even better you would challenge mobility, stability, AND strength!

Let’s look at the swinging of kettlebells. Strength Coach, Bret Conteras, has showed that movements like kettlebell swings offer huge not only vertical forces, but horizontal as well (9). This is important as athletics and functional movements usually not happen just up and down, but with forces going horizontally as well!

How about the fact that the kettlebell squat variations offer us two tremendous benefits the barbell can not. We can use drills like the Goblet squat to actually pattern deep squatting patterns. Instead of trying to add more unnecessary forces to our low backs with powerlift types of squats to hit the hamstrings and glutes, going deeper in the squat does the same while adding flexibility to the body.

Maybe you are thinking this is just MY opinion, but listen to what expert spine specialist, Dr. Stuart McGill, says about the squat, “..gluteus medius activation is too load and gluteus maximus activation is relatively low until quite deep in the squat position.” (10)

Once we pattern the squat with drills like the Goblet squat we can challenge strength and stability with heavy one-arm front kettlebell squats, or more load and force emphasis with double kettlebell front squats. The ideal is to rotate to get the benefits of both.

I could go on and on about many of the top benefits that the kettlebell provides that not only makes it effective, but foundational to ANY strength training program. Concepts of independent implements which allow for the body to learn control while creating force. Dozens of loading patterns that allows to challenge strength and stability, and so much more.

I like to think that it is up to the other training methods to step-up and question can THEY be doing things better like the kettlebell?

This week you can find out so much more not just how we combine kettlebells and Ultimate Sandbags, but our unique take on kettlebell training after teaching kettlebells for over 20 years. Check out our kettlebell programs 35% off this week with code “save35” HERE and see kettlebell workouts in a whole new way!


1. Otto W III, Coburn J, Brown L, and Spiering B. Effects of weightlifting vs. kettlebell training on vertical jump, strength, and body composition. J Strength Cond Res 26: 1199–1202, 2012.

2. Gullett, Jonathan C; Tillman, Mark D; Gutierrez, Gregory M; Chow, John W. A Biomechanical Comparison of Back and Front Squats in Healthy Trained Individuals. Journal of Strength & Conditioning Research:January 2009 – Volume 23 – Issue 1 – pp

3. Lake J and Lauder M. Kettlebell swing training improves maximal and explosive strength. J Strength Cond Res 26: 2228– 2233, 2012.

4. Yessis, Michael. Explosive Plyometrics. Ultimate Athlete Concepts, 2009, 1st Edition.

5. Jay K, Jakobsen M, Sundstrup E, Skotte J, and Jørgensen M, et al. Effects of kettlebell training on postural coordination and jump performance: A randomized controlled trial. J Strength Cond Res 27: 1202–1209, 2013.

6. Farrar R, Mayhew J, and Koch A. Oxygen cost of kettlebell swings. J Strength Cond Res 24: 1034–1036, 2010.

7. Manocchia P, Spierer D, Lufkin A, Minichiello J, and Castro J. Transference of kettlebell training to strength, power and endurance. J Strength Cond Res 27: 477–484, 2013.

8. Saeterbakken AH, Fimland MS. J Strength Cond Res. 2012 Oct 23. Effects of body position and loading modality on muscle activity and strength in shoulder presses.

9. Conteras, Bret. “Kettlebell Swings: Go Heavier for Greater Glute and Hamstring Activation. Bretconteras.com. http://bretcontreras.com/kettlebell-swings-go-heavier-for-greater-glute-and-hamstring-activation/

10. McGill, Stuart. Ultimate Back Fitness and Performance. Stuart McGill, PhD; 2004, 3rd Edition