I'll admit it: I've had a historically negative attitude toward kettlebells, at times vehemently so. I'm responsible for numerous iterations of the following dialogue:

CLIENT: What's the best kettlebell exercise?
ME: Putting it away.

But in my old age (barreling toward thirty with no pit stops in site), I've departed from my wayward ways and become far more contemplative and philosophical. As a product of this transformation, I've realized that my opposition has been misguided: a kettlebell is just a heavy thing with a handle; it's done nothing wrong. Accordingly, the focus of my discontent has shifted from the implement itself to inaccurate or exaggerated claims regarding kettlebells' use in strength and conditioning.

In the spirit of Stewart Griffin's Compliment Sandwich approach to office management, let me preface the following discussion by saying the kettlebell is an excellent training tool. It offers great opportunities for creativity in training and can be used to introduce unique stimulus. By no means is this article intended to either offend kettlebell users or instructors or to dissuade anyone from the use of kettlebells—I in fact encourage their use and include them in both my clients' and my own training. They're a useful addition to any athletic or fitness training program. But as is the case with any other implement, successful training is dependent on its appropriate use.


The Beef

Those principles of strength training and metabolic conditioning that are successful with kettlebell training are not unique to kettlebells; that is, those same principles can be applied equally well with at least one other single training implement (the dumbbell), and certainly far more effectively with an array of implements. These fundamental practices of movement and programming are not implement-specific.

Let's consider some particulars.


Instability

Because the center of mass of the kettlebell is neither centered at the handle nor necessarily fixed, it's often claimed the implement offers an unusual degree of instability that develops greater athleticism. This appears sound, and instability is an important addition to any athletic training, but I will argue that a kettlebell as used in the majority of typical movements is not remarkably unstable, and is actually more stable than other implements would be when used for an identical movement.

Because the center of mass of the kettlebell is significantly distant from the handle, it will produce an overwhelming force in a single primary direction when held overhead with the handle above the center of mass (the center of mass cannot center itself under the handle because it's blocked by the supporting arm). Using the kettlebell snatch as an example, the force will always be directed backward as the kettlebell is flipped into the overhead position. This unidirectional pull is consistent and therefore entirely predictable, which means it is not by definition genuinely unstable. This predictability allows easy compensation by the athlete, and that planned compensation actually reduces the athletic demand of the movement in question.

Compare the kettlebell snatch to a dumbbell snatch. The argument is that the dumbbell will create a direct downward force and is therefore easier to control than the kettlebell, but this is true only of a motionless dumbbell supported on a perfectly vertical arm. Because the dumbbell's mass is essentially centered on the handle, it has a tendency to pull in any direction nearly equally if allowed to move outside of this perfectly vertical support position. A motionless kettlebell supported in an arm slightly off vertical to balance its off-center pull has no more tendency to move than the dumbbell. If the supporting arm is held perfectly vertical, the kettlebell will pull in a single direction, effectively demanding a single, opposing pull to stabilize it. The dumbbell, on the other hand, requires approximately equal stabilization in all directions, meaning its net instability is greater than the kettlebell's. Furthermore, because the center of mass of the kettlebell is significantly lower than the handle, it lowers the center of mass of the arm-kettlebell unit, decreasing the moment on the shoulder and making it easier to control than another implement of equal weight.

The previous argument of course applies only to movements in which the kettlebell is removed from the ground and the center of mass is below the handle. In instances in which kettlebells are used as bases for pressing movements or in the bottoms-up position, athletic demand is greatly increased along with instability.


Hip Extension

Anyone who can spell athleticism understands that powerful hip extension is the foundation of effective athletic movement. Hip extension, however, is not an isolated event and a movement that demands hip extension is not necessarily appropriate or effective for all types of athletic development.

The Olympic lifts—or at least the power variations thereof—are invariably considered the greatest developing tools for explosive hip movement. No other movements have the ability to produce and train so much vertically-oriented power.

Two of the most common kettlebell movements are the snatch and the clean. By name, they're identical to the lifts, and this is often interpreted to mean they produce the same effects. Unfortunately, the kettlebell variations of these movements are not only dramatically removed from those after which they're named, but in the most critical manner possible.

The key to the Olympic lifts' effectiveness is the vertical direction of explosive force. The path of the bar in the snatch, clean and jerk is very close to a straight line. The bar in the snatch and clean will travel back toward the lifter slightly on its way up, and finish with a minor backward movement as it is brought over the lifter. Similarly, in the jerk, the barbell travels straight down and then up before being brought slightly backward to its final position over the lifter.

The foundation of kettlebell movement is the swing, and it is with a swing that both the kettlebell snatch and clean are initiated (most commonly—there are deadhang variations that we'll address later). This swinging motion is the result of hip extension of a critically different nature than that seen in the Olympic lifts—the hip extension in the swing is oriented horizontally, not vertically. Instead of what is described in the Olympic lifts by Coach Mike Burgener as a vertical "shrug" of the hips, we see a horizontal "thrust". In addition to orienting the hip extension in a different direction, the swing eliminates the key to the enormous power generated in the Olympic lifts—the double knee bend.

The common kettlebell snatch resembles the snatch in no other way but the ending position—implement overhead in an extended arm. Apart from this, the movements are disparate in every meaningful regard. The notion, then, that the kettlebell variations of the Olympic lifts deliver the same benefits is inaccurate. To be clear, this of course does not mean the swing variations of the snatch and clean do not deliver their own benefits to athleticism—most obviously, they have immense potential as a mode of metabolic conditioning, development of the posterior chain musculature, and deliver a high level of punitive suck for whiny athletes.

As mentioned above, the kettlebell snatch and clean can be started from a deadhang—that is, with the kettlebell starting from a motionless hang position (or the floor) and brought essentially straight up instead of being swung. It's possible with this variation to much more closely mimic the traditional lifts, although impediments still exist. For example, in the barbell lifts, the bar is brought into the hips to keep it as close to the body as possible, allowing the vertical elevation and much greater loading. Because the kettlebell's largest part is both centered horizontally on and located below the handle, the implement cannot be brought into the body in the same manner without potential sterilization and/or severe pain of a fairly embarrassing nature.


Lifting Backward

Continuing on the subject of the kettlebell versions of the snatch and the clean, arguments have been made that kettlebells offer the additional benefit of allowing the performance of the eccentric portion of the movement, which is absent from the snatch and clean. In the traditional barbell lifts, it's explained, the lifter drops the weight after completing the concentric movement, whereas in the kettlebell variations, the lifter must control the weight in both directions, thereby developing greater athleticism.

Like the instability argument, this idea does have merit. Of course athletes must develop the ability to absorb and control eccentric forces and any conditioning program that ignores this need is incomplete. The comparisons of the kettlebell lifts to their traditional counterparts, however, fail to consider either respective loading or training objectives.

For example, an individual of 85 kg with a 100 kg maximum snatch would commonly snatch a 24 kg kettlebell. Clearly this is a load that he could not only bring up but back down numerous consecutive times. To compare that to a traditional snatch of 100 kg is inappropriate—once we reach near maximal loading in a movement dependent on speed, we have exceeded the ability to reverse the motion. Lowering a load of this magnitude would be possible for some people, although the limiting factor would likely be grip strength more than anything else.

If we compare the movements in the context of equal loading, the situation is entirely different. We can say a single-arm kettlebell snatch with 24 kg is equivalent to a barbell power snatch of 50-60 kg (padded for the 2-arm advantage of a barbell). Not only is it possible for our 85 kg individual to easily lower this load, it's common when performing multiple reps of the movement.

In addition, it's inappropriate to compare kettlebell movements intended for GPP or athletic conditioning to Olympic lifts intended specifically for competitive weightlifting. If we compare athletes using the two means for similar ends, i.e. GPP, we'll see the barbell lifts typically performed in their power versions from hang positions with controlled eccentric portions among multiple consecutive reps. From this properly adjusted perspective, the apparent kettlebell advantage disappears.


Strength Development

A critical component of any fitness or athletic training program is strength development, and kettlebells are commonly promoted as excellent—if not unparalleled—strengthening tools. The idea is pretty simple: kettlebells are heavy, therefore lifting them will increase strength. To a point, this is indeed true. But it does ignore the most fundamental principle of strength training: progressive overload. To continue increasing strength, an athlete must continue on average over time to lift more weight (or at least increase resistance—not necessarily the same thing).

If we're to believe a single kettlebell is a complete fitness solution, problems arise: that single kettlebell will not be changing its weight anytime soon, so the amount of resistance it can provide in any given movement will never change. Progressive overload doesn't exist. Now it will be argued that in the beginning, an athlete may be able to complete only 2 repetitions of a given movement with his or her kettlebell, and that over time with training, he or she will be able to complete 5 repetitions, indicating an increase in strength. This is absolutely correct.

If you read the Big Kids' Muscle-up article in PM 18, you'll recall my discussion of this same issue, but we'll go ahead and repeat it for the uninitiated. In fact, I'm going to quote myself (as I learned from Charles Shaw, the key to successful writing is self-plagiarism):

"Imagine deadlifting the same load for ten years—day one, that load may allow you to perform only a single rep. Eventually you'll likely be able to perform several successive reps—some day, you may be able to 100. But the ability to perform 100 reps of a given movement with given a load does not translate into the ability to lift a significantly greater load with that same movement (think Jazzercise practitioners—they can move a two-pound dumbbell about a million times). Beyond a certain threshold, strength development is replaced by local muscular endurance development. To continue developing strength, the resistance must be increased incrementally. This is the most basic concept of resistance training—progressive overload."

Now, there are of course ways to increase resistance for a working muscle without technically increasing the load being lifted—manipulation of positioning can increase moments, thereby increasing the amount of force a muscle has to generate to complete a give movement. Unfortunately, this idea has limited application, primarily to gymnastic-style bodyweight training. I can increase the moment on my back/hips in a deadlift by allowing the load to drift away from my legs, but I have only a couple inches to play with (don't laugh), and more importantly, this affects only the hip extension component of the movement—the force needed for knee extension, for example, remains the same regardless of how distant the load is from me.

So essentially what we'll see with a single kettlebell (or any other single fixed-weight implement) is an initial period of strength development that will eventually shift into metabolic conditioning. The only way to continue increasing strength would be to increase the weight of the implement. The solution? Get more of whatever you're lifting. Which leads us convenietntly into the next topic…


Cost Effectiveness

If we agree that a single kettlebell is adequate for a complete fitness or athletic conditioning program, the cost effectiveness is great—as an athlete, I can spend about $150 and be set. But we've already discussed the more important limitations of this approach.

As a trainer, I can buy a few kettlebells of different weights have all of my clients covered. With this setup, assuming I'm working with a single client at any given time, I can even prolong that client's strength development by periodically progressing him or her to the next heaviest kettlebell in my collection.

Let's compare some costs to the kettlebells biggest competitor—the dumbbell. We won't even bother comparing costs with an Olympic barbell and set of training bumpers and change—obviously this would be far more expensive than the collections of either kettlebells or dumbbells.

To equip yourself with a complete collection of single quality kettlebells, 11 implements of weights 9 lb – 106 lb, you're going to spend about $1370 or $124/implement. To equip yourself with the same number of dumbbells of similar weights, you'll spend about $620 or $56/implement.

For less than half the cost of outfitting yourself with a complete set of quality kettlebells, you can outfit yourself with a matching set of quality dumbbells; for about the same price, you can even get a pair of dumbbells of each weight. For $5.00 more than the kettlebell set, you can get single dumbbells in 5-lb increments from 5 lb all the way to 105 lb. No matter how you consider it, dumbbells are more cost effective.

This in no way means kettlebells—or a barbell setup for that matter—should not be purchased—what it means is that it's important to consider the budget of your practice or facility and prioritize equipment purchases accordingly. This may mean for you an initial purchase of one or two kettlebells and several dumbbells—it depends on the circumstances.

Kettlebells

Following is a list of all the common kettlebell weights and prices from a major supplier.

9 lb - $90
13 lb - $98
18 lb - $100
26 lb - $83
35 lb - $90
44 lb - $100
53 lb - $110
62 lb - $130
70 lb - $140
88 lb - $180
106 lb - $248
---
524 lbs - $1369
$2.61/lb

11 implements - $124/implement


Dumbbells

Prices are based on quality rubber hex-head dumbbells from a major supplier.

Matched to KBs
10 lb - $11.90
15 lb - $17.85
20 lb - $23.80
25 lb - $29.75
35 lb - $41.65
45 lb - $53.55
50 lb - $59.50
60 lb - $71.40
70 lb - $83.30
90 lb - $107.10
100 lb - $119.00
---
520 lbs - $618.80
$1.19/lb

11 implements - $56.25/implement


Complete singles
5 lb
10 lb
15 lb
20 lb
25 lb
30 lb
35 lb
40 lb
45 lb
50 lb
55 lb
60 lb
65 lb
70 lb
75 lb
80 lb
85 lb
90 lb
95 lb
100 lb
105 lb
---
1155 lbs – $1374
$1.19/lb
21 implements - $65.40/implement


Keep Playing with Your Bells

Again, this article is in no way intended to suggest that kettlebells do not belong in athletic or fitness training—they, like other implements, have their place and something unique to offer. But inaccurate or exaggerated claims do the implement a disservice and have the potential to severely damage the credibility of instructors, trainers and athletes. Let's let them be what they are and do what they can do. That's right, little buddies—I love you just the way you are.