Did you ever see Clash of the Titans?
Krakens… Medusa… Zeus… it was a battle of epic proportions.
And today I bring you a clash of the GYM titans, as I compare dumbbells vs kettlebells to see which kit is better for building muscle! Does one really rule over the other, or should you use both for even better results?
Check out this email from website member Rachel:
“Hi Russ! A personal trainer at my gym told me that using kettlebells will result in significantly better muscle growth than using barbells or dumbbells. Is this true? Are kettlebells as superior as he’s claiming?”
“It’s Not About The Size… It’s What You Do With It!”
The above statement is very true here (and it’s also fantastic for protecting a fragile ego).
You see, your body doesn’t really recognize the difference between a kettlebell and a dumbbell (or a barbell). It feels resistance, that’s all. How you use that resistance can have a huge impact on your results.
For example, training with dumbbells usually promotes a very different style of training than training with kettlebells – one is slow and controlled, and the other is fast and explosive. That’s what makes the real difference between these two pieces of kit, so that’s what we’ll look at in this article.
Now for those of you who are brand new to kettlebell training, or who have perhaps unfairly dismissed it in the past as some kind of “new fad”, let me assure you it’s very effective – and it’s definitely not new! Kettlebell training originated in Eastern Europe about one hundred years ago and it has been a mainstay in the training programs of top athletes for as long as I can remember.
It really shines when the training objective is to increase EXPLOSIVE POWER, one of the key reasons being because the shape of the kettlebell lends itself nicely to fast full body exercises. Take snatches for example; the explosive motion of this exercise make it a great tool for athletes in nearly every sport around the world.
It’s an exercise I’ve programmed with my clients for many years. Take a look at this great tutorial to perfect your form:
But this is where things get tricky…
Explosive strength is one thing, and muscle growth is another. The email above specifically asked if kettlebells are better than dumbbells for building muscle, so that’s what we need to find out.
In order to maximize hypertrophy (muscle growth) we must focus on time under tension, not speed, so this is where traditional training with dumbbells and barbells works incredibly well.
A 2012 study published in the Journal of Physiology indicated that the so-called “sweet spot” for time under tension is around 40-60 seconds. The study had one group of trainees performing three sets of x12 leg extensions at a regular pace, while another group performed three sets of x12 leg extensions with a much slower tempo to ensure muscle failure was achieved by the final rep.
Interestingly, the group who slowed things down built significantly more muscle! (1)
And what about STRENGTH?
Well, we can answer that question by looking at a great 2011 study from researchers at California State University, Fullerton. The researchers did a direct comparison between kettlebells vs dumbbells to see which could yield the better strength gains (perfect for this article, huh?!).
In this study they had one group of participants using a 16kg kettlebell to perform a combination of:
- Goblet squats
- Accelerated swings
- Kettlebell Swings
And a second group of trainees used free weights with around 80% of their max for the following movements:
- High pulls
- Barbell squats
- Power cleans
(As you can probably see, these exercises were selected due to their similarity.)
Interestingly, the barbell/dumbbell based exercises came out on top.
The results, which were published in the Journal of Strength and Conditioning Research, showed that trainees unlocked a 15% increase in their squat one rep max (compared to a 5% increase in the KB group), a 10% strength increase (vs 4%) and a 4% improvement to their vertical leap (vs 1%). (2)
How To Apply These Findings For Maximum Results
Research seems to support the idea that kettlebells are superior for improving explosive performance, but barbells and dumbbells are king for strength and muscle growth.
But here’s the thing…
The worst thing you can do is commit to one style of training! Seriously, I use barbells, dumbbells, kettlebells, resistance bands, machines, medicine balls… they all serve a purpose!
In terms of the research above, the main reason dumbbells “won” is because the exercises we associate with dumbbell training lend themselves better to increasing time under tension, and that’s the key to muscle growth, so it’s not really about which equipment is better or worse.
I mean, you could achieve the same muscle building results with a kettlebell if you changed your training style to maximize time under tension and, likewise, there are numerous free weight exercises which could mirror the explosive nature of kettlebell training (heavy barbell cleans, dumbbell snatches, etc).
So like I said earlier; it’s what you do with it that counts!
- Burd N. A., et al. Muscle Time Under Tension During Resistance Exercise Stimulates Differential Muscle Protein Sub-Fractional Synthetic Responses In Men. J Physiol. (2012)
- Otto W. H., et al. Effects Of Weightlifting Vs. Kettlebell Training On Vertical Jump, Strength, And Body Composition. J Strength Cond Res (2012).