DUMBBELLS VS KETTLEBELLS: WHICH IS BETTER FOR BUILDING MUSCLE?
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!
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 THE SIZE… IT’S WHAT YOU DO WITH IT THAT COUNTS!”
The statement above is fantastic for protecting a fragile ego, and it’s also very true here.
You see, your body doesn’t really recognize the difference between a kettlebell and a dumbbell (or a barbell). It feels resistance, and how you use that resistance will determine your results.
That said, dumbbells and kettlebells usually invoke two very different styles of training – one is slow and controlled, the other is fast and explosive – and THAT’S what we will be looking at today.
Kettlebell training originated in Eastern Europe over a hundred years ago and has been a mainstay in the training programs of top athletes for as long as I can remember. It really shines when the goal is EXPLOSIVE POWER, because the shape of the kettlebell lends itself nicely to fast full body exercises like snatches.
The fierce nature of a move like this make it a very effective training tool for athletes in almost every sport. It’s one of my favourite exercises, and I program it with clients regularly.
Take a look at this tutorial to perfect your technique:
But this is where things get tricky…
Explosive strength is one thing, and muscle growth is another.
If we wish to maximize hypertrophy we must focus on time under tension, not speed, and this is where traditional training via dumbbells and barbells works very well indeed.
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 actually pitted kettlebells vs dumbbells to see which training kit could yield greater strength gains (perfect!).
One group of trainees used a 16kg kettlebell to perform a combination of:
- Goblet squats
- Accelerated swings
- Kettlebell Swings
Another group of trainees used 80% of their max for the following free weight 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)
… BUT DON’T BE A D**K!
Research seems to support the idea that kettlebells are superior for improving explosive performance, while 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, balls… it all serves a purpose!
In terms of the research above, the main reason dumbbells came out on top is because the exercises we associate with dumbbell training lend themselves better to increasing time under tension. That’s the key to muscle growth, not which “kit” is better – and you could achieve the same results with a kettlebell if you changed your training style to maximize time under tension.
Likewise, there are numerous barbell-based movements which mirror the explosive nature of kettlebell training (heavy barbell cleans, dumbbell snatches, etc.).
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).