Often when I begin teaching someone how to train with kettlebell one of the first questions I get is.
“Can I just use a dumbbell instead?”
Well, it turns out dumbbells and kettlebells are different tools.
While you can sometimes use different tools for the same purpose, sometimes you can’t.
Learn more about the differences between dumbbells and kettlebells below
Kettlebells are not the same as dumbbells.
While they are often made of the same material and are often used for the same purpose, they have different shapes. The difference in shape makes a huge difference.
It is like the difference between a fork and a spoon. They are often used for the same purpose: feeding yourself. They are often made of the same material, metal or plastic. But they are shaped differently. Sometimes either will work just as well. You can eat a moist piece of cake with a spoon or a fork. But try eating soup with a fork (or pasta with a spoon) and you will realize that the shape matters.
Kettlebells and dumbbells are often used for the same purpose: getting fit. They are often made from the same material, iron or steel. But they are shaped differently. The kettlebell has the bulk of the weight underneath the handle, while the dumbbell has the bulk of the weight divided in half and on either side of the handle. Sometimes both work just as well (such as in a single leg deadlift). But try swinging a dumbbell between your legs or doing a hammer curl with a kettlebell and you will realize the shape matters.
And like the spork, you should avoid anything that looks like a hybrid of a kettlebell and a dumbbell.
What is each better for?
Kettlebells are better for full-body exercises, and dynamic exercises.
Dumbbells are better for isolating individual muscles.
If I had to pick one for myself I would pick the kettlebell. Why?
Full Body exercises are more time-efficient than isolation exercises.
It is faster to do an exercise (like a swing) that hits almost your entire body instead of doing one exercise for each of the dozens of muscles to work them individually.
Dynamic Exercises mean that you don’t need as many sizes.
This is because of physics. Weight is a Force. Force = Mass x Acceleration (Newton’s Second Law). In a dynamic exercise, you can increase the acceleration, and this increases the force in a similar way.
For this reason, you can get away with 3 kettlebells for the rest of your life. But with dumbbell training, you generally need a set of at least 10 different sizes. Often more.
Having the handle further away from the weight gives you more options for how to hold it and transition between exercises. Also, since you can link exercises more effectively, your practice of kettlebell training is more fun and exciting.
It is important to note that the kettlebell is not better than the dumbbell, just different. If you want to be a bodybuilder dumbbells are a better tool than a kettlebell. Isolation exercises also have a much shorter learning curve. I can teach you to do a bicep curl in less than one minute. Learning the kettlebell swing will take at least a few weeks.
How can the shape make such a difference?
The main reason is because of the options for holding it, and where the weight is in relation to how you are holding it.
With a dumbbell, you can hold it one of two ways. By the handle or by the weight. When you hold the handle the weight is always evenly distributed on either side. If you hold it by the weight on one side the other side will almost always have to be below you.
With a kettlebell you can also hold it by the handle or by the weight. But when you hold it by the handle the weight can be:
- Below the handle towards the ground
- Above the handle towards the sky (Known as Bottoms Up position)
- Resting on your forearm while you grip the handle (Known as the Rack position)
- “Floating” in front of the handle while you hold the handle
And you can transition between all of these without putting the kettlebell down. This is how we can flow through multiple very different exercises without setting the kettlebell down.
When you hold it by the weight your hand will be under it like holding a tray. Once you get skilled with the kettlebell you will be able to transition there (and back).
Additionally, because the weight doesn’t shorten the handle you can grip the kettlebell handle with two hands. You can also switch between two hands and one hand without putting the kettlebell down.
With a dumbbell, you can only use two hands while gripping the weight of the dumbbell instead of the handle. This is not how it is designed to be used and I have seen dumbbells come apart from being used like this. A good quality kettlebell is one solid piece of iron or steel and will never come apart.
The Turkish Get Up
This exercise deserves a special note in the discussion. This is because it really appears that the dumbbell and kettlebell are equivalent for it, but this is not the case.
The reason for this is how the wrist and shoulder react to the load being directly on top of the forearm (with a dumbbell) to being supported on the outside (with a kettlebell).
When the kettlebell is on the outside you can get your wrist completely straight. With a dumbbell, you have to extend the wrist slightly. When your wrist is completely straight with the weight on the outside the weight will tend to pull your arm to a true vertical. Also, the way the nerves communicate with the shoulder helps you activate your shoulder more efficiently when the wrist is straight.
A deeper discussion of why these things occur gets very technical very quickly and is beyond the scope of this article.
Another important note is that this is specific to the Turkish Get Up and how it uses the shoulder in so many different positions putting it through a full range of motion. In a movement such as a dumbbell bench press, the same logic does not apply.
How the dumbbell helps isolate muscles
The advantage of the dumbbell with the weight on either side of the handle is that it moves with your hand and the weight won’t move to a different position.
For example, take an exercise like a bicep curl. The weight of the kettlebell hanging down at the bottom will rest on the back of the forearm on a standard bicep curl. This is slightly inconvenient but not that big an impedance to the exercise.
But take a reverse bicep curl now and at the top the kettlebell is hanging on your thumb and the inside of your forearm, which is very uncomfortable.
Or the hammer bicep curl. Now you have to end in the bottoms-up kettlebell position. This will make it impossible to handle a decent amount of weight to really hit your biceps.
Or the variation where you rotate your wrist while curling the weight. This doesn’t really work at all.
But all these variations work excellently with a dumbbell which always stays with your hand. And for isolating different muscles within the arm this can be important.
However, hitting your bicep in 6 different ways can get time-consuming and unless you want to be a bodybuilder is not very useful. Also, it is important to remember that this won’t help burn your arm fat faster. You can choose which muscles to work but your body will pick where the fat it burns comes from. You could be doing arm exercises and burning fat from your face. For this reason, if the goal is fat loss then a full-body exercise is better. That’s why bodybuilding workout plans have lots of exercises and lots of cardio and intense dieting.
Remember, neither tool is “better” than the other. Neither a hammer or screwdriver is better than the other. Each is just different, with certain advantages and disadvantages.
If your goal is bodybuilding a good set of dumbbells very useful.
If your goal is time-efficient, fat burning, and muscle building workouts a kettlebell is more useful.
If your goal is to outfit a home gym cheaply and with as little space as possible kettlebells win.
If you don’t want to spend time learning and practicing exercises then dumbbells are a better fit.
If you want a portable gym you can take outside for a workout then kettlebells win.
For how I train myself and my clients kettlebells are the clear winners. But we all have different goals. Take the time to decide which is a better fit for your life.
And if you want to know more about learning to train with kettlebells check out my article on the two best kettlebell exercises.
And if you are ready to invest in a kettlebell for working out at home check out my guide to buying your first kettlebell.