Kettlebells Vs Dumbbells: Which Is Better?

Kettlebells and dumbbells are both great, but they serve quite different purposes.

Are you trying to:

• Improve explosive power?
• Enhance biomechanics?
• Gain strength?
• Build muscle?

This is not so much to do with the equipment itself (they’re both just lumps of iron) but rather the exercises and styles of training they enable you to do.

For example, the odd shape of a kettlebell makes it a very good tool for performing explosive exercises which duplicate movement patterns from most sports (think cleans, swings, etc), meanwhile traditional barbells and dumbbells are designed to handle extremely heavy loads.

Let’s get into the science on this topic.

Goal: Explosive Power

Winner: Kettlebells.

Originating in 1700s Russia, kettlebells (‘Girya’) are renowned for their odd shape. Having the handle of the weight on top of the bell makes it easier to perform momentum-based exercises, and that makes this the perfect tool for improving explosive strength.

When using kettlebells, athletes can mimic the same movement patterns they’ll perform in their chosen sport, while focusing on building speed and power. (1)

That’s why they’re popular amongst MMA fighters, baseball players, and footballers.

Alongside the benefits of sports specificity, a 2012 study actually showed that kettlebell training places significantly less load on our joints, which also makes them a solid choice for athletes looking to stay clear of injury. (2)

Goal: Biomechanics

Winner: Kettlebells.

Let’s face it, athletes who don’t pay attention to exercise biomechanics get injured more often.

We can see a fine example of this by looking at the WWE Superstars of the 1980s.

Their sole focus was on looking great, so most of them trained like bodybuilders only to wind up riddled with injuries by the time they hit their mid-30s.

This reason for this is because most bodybuilding-style exercises take place in the sagittal plan (up and down / back and forward), but wrestling and the majority of other sports (and some would argue life itself) take place in the transverse plane (twisting, catching, etc), resulting in lots of unnecessary pressure being placed on muscles which had not been fully conditioned to handle the stress.

This is where kettlebells really excel.

For instance; a 2013 study from Denmark showed that kettlebell swings activate the medial hamstring (semitendinosus) more than the lateral hamstring (biceps femoris). Now, the semitendinosus plays a greater role in running, so while you could effectively train your hamstrings to look good with both a kettlebell swing or a seated leg curl machine, the swings would be a far superior option for someone who is following a sprint-based training program and looking to improve their running ability. (3, 4)

Interestingly, an exercise like kettlebell swings also produces a lot of horizontal force. Research suggests that horizontal ground reaction force is better than vertical ground reaction force when it comes to improving acceleration, so this is another reason why kettlebell swings would be a fantastic choice for sprinters! (5, 6)

Goal: Strength

Winner: Dumbbells.

Barbells and dumbbells are the clear winner when it comes to boosting your strength, because they allow you to load exercises with far greater resistance than kettlebells.

Also, their shape is designed to maximize brute force.

A 2012 study actually compared the strength gains made from a program consisting of either a selection of kettlebell exercises versus their barbell/dumbbell counterparts, and the results were startling.

Kettlebell Exercises	Barbell / Dumbbell Exercises
Goblet Squats	High Pulls
Accelerated Swings	Barbell Squats
Kettlebell Swings	Power Cleans

While all of the trainees saw a strength increase, those using barbells/dumbbells achieved the best results.

This included a 15% improvement to their squat max (compared to only 5% for the kettlebell group), plus a 4% boost to their vertical leap ability (versus 1% for the KB group), and a 10% strength increase (compared to 4% for the KB group). (7)

Goal: Hypertrophy

Winner: Dumbbells.

You can build muscle with either piece of kit, but the training style which has been shown to maximize hypertrophy is better suited to barbells and dumbbells.

Because while kettlebells are built for speed, the best way to build muscle is via a combination of progressive overload and time under tension, which requires a focus on overloading the weight and slowing the tempo. (7)

When we increase the weights over time we get stronger, and provided your diet is sufficient in protein you will build muscle. Eventually you’ll reach a ceiling in terms of how heavy you can go, so this is where time under tension training comes into play, as it enables you to elicit further muscle growth without needing to subject your muscles (and particularly your joints) to crazy loads. Studies show the sweet spot for this type of training is 40-60 seconds. (8)

Russ’ Take-Home Advice

As you can see, both pieces of kit have advantages and disadvantages.

This is where clever programming comes into play.

You’ll meet countless people who swear by either one thing or the other, but I’ve always encouraged clients to see that every tool in the gym has a purpose (that includes dumbbells, barbells, kettlebells, cable stations, resistance bands, Smith machines, and more!), and the real “secret” is learning how to use the right tool for the job.

As you can see above, if your goals are to improve explosive power and biomechanics for sport then you’ll absolutely love the benefits of kettlebell training, whereas if it’s straightforward case of building muscle and getting stronger then old-school barbells and dumbbells are superior.

I’ll leave you with the words of a meta-analysis published in the Strength and Conditioning Journal which looked at the findings of 20+ studies on kettlebell training:

“The majority of studies support the use of kettlebells for improving explosive power, but the evidence for using them for improving overall strength is still equivocal.

Studies investigating the biomechanical properties of kettlebell training have been more fruitful, though. Researchers have so far found that kettlebell swings in particular have certain benefits which may make them very useful for training athletes.” (10)

Further Reading:

If you enjoyed this blog, then you’ll probably also like reading these.

>> Trap Bar Deadlift Vs Regular Deadlift
>> Stallone Was Right: Circuit Training Rocks!
>> The Rules To Ripped

References:

1. Vancini R. L., et al. Kettlebell Exercise as an Alternative to Improve Aerobic Power and Muscle Strength. J Hum Kinet (2019).
2. Lake J. P., et al. Kettlebell swing training improves maximal and explosive strength. J Str Cond Res (2012).
3. Zebis M. K., et al. Kettlebell swing targets semitendinosus and supine leg curl targets biceps femoris: An EMG study with rehabilitation implications. Br J Sports Med (2012).
4. Jonhagen S., et al. Amplitude and timing of electromyographic activity during sprinting. Scand J Med Sci Sports (1996).
5. Lake J. P., et al. Mechanical demands of kettlebell swing exercise. J Strength Cond Res (2012).
6. Keogh J. W. L., et al. Transference of Strength and Power Adaptation to Sports Performance-Horizontal and Vertical Force Production. Str Cond J (2010).
7. Otto W. H., et al. Effects Of Weightlifting Vs. Kettlebell Training On Vertical Jump, Strength, And Body Composition. J Strength Cond Res (2012).
8. Krzysztofik M., et al. Muscle Hypertrophy: A Systematic Review of Advanced Resistance Training Techniques and Methods. Int J Environ Res Public Health (2019).
9. 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).
10. Bearsdley C. M. A., et al. The Role of Kettlebells in Strength and Conditioning: A Review of the Literature. Str Cond J (2014).