Kettlebells and tension, "virtual force", beneficial inefficiency

Sean M

Quadruple-Digit Post Count
Forgive me if this is incoherent. It makes sense in my head; I have a hard time organizing my thoughts sometimes, especially for something I've been mulling over sporadically.

If tension is strength, and strength is force against resistance, then more tension means more force (more strength displayed). Thus, an exercise which stimulates/recruits more muscle tension than another, will induce a greater strength adaptation. 'Strength adaptation' being an increase in the body's ability to produce the force needed to overcome more resistance (lift more weight).

The more efficient the load/lifter system, the more load that can be applied. This is why the barbell allows for the heaviest weights: the exercises are mechanically efficient. In the press, for example, the center of load is stacked on top of multiple joints and muscle energy can efficiently be transferred to getting the load up in a straight line over the center of gravity. Squat and deadlift are similar: the load is over the midfoot, and the lifter/load system moves efficiently around that center to get the weight up.

The offset handle of a kettlebell introduces inefficiency (e.g. I believe most people can barbell overhead press more than they can double kettlebell press?). In the kettlebell press, the load is not above the wrist, but next to it. This limits the amount of weight that can be lifted. BUT, does less weight always mean less force (tension) recruitment?

Can two unequal loads recruit the same (or the lesser weight recruit/demand more) tension, due simply to differences in leverage? Is this the "secret sauce" of kettlebell strength training: the same (or more) tension with less weight?

I think of something like the way up from a heavy barbell snatch, say 300lbs. The movement is to stand up with a load overhead. Compare that to a 48kg getup - also standing up with a load overhead. AFAIK, more people can do a 300lb snatch than could do a 100lb get-up (kettlebell or barbell), because (perhaps?) the lighter getup requires more tension (?), due to inefficient leverages, than does the stand-up segment of a barbell overhead squat.

Bottoms-up pressing is another example. Has anyone compared an EKG or something similar of a 24kg bottoms-up press compared to a ~110 pound barbell overhead press? Or perhaps more equivalent: 50lb dumbbell press? Or even BU to regular kettlebell press with the same weight?

In other words, is weight/load the master variable of strength training, or is tension? Which comes first, load or tension? How exactly (and to what extent, compared to the barbell/lifter system) does mechanical disadvantage/inefficiency create virtual tension that matches or exceeds that generated by a higher absolute load on a barbell?

An articulate answer would go a long way to advocate for kettlebell strength training for skeptics who scoff at relatively puny absolute weights. I'm reminded of the quote from Pavel somewhere about him challenging 300-pound bench pressers to one-arm press a 40kg at a strength convention, which many couldn't do, even with assistance getting it into the rack position.
 

Antti

More than 2500 posts
First of all, having the load next to the wrist, not above it, is not always mechanically inefficient.

When it comes to straightforward and efficient training, the load is always the most simple and the most effective variable. This is something that I feel should be emphasized.

I hesitate to pit the TGU against the overhead squat. I would say the overhead squat demands more mobility and skill than the TGU. It is, per se, the harder exercise. Just that people don't do a certain exercise does not make it harder.

The bottoms-up press demands a different strength compared to the overhead press, whichever implement you choose. The comparison does not make sense to me.

In the end, there is strength. The advantage of the kettlebell is the ease how it is trained and expressed fast; power.

Why make a hammer out of a wrench? Sure, in a hurry it serves as one, but in general; why?
 

Papa Georgio

Triple-Digit Post Count
In other words, is weight/load the master variable of strength training, or is tension? Which comes first, load or tension? How exactly (and to what extent, compared to the barbell/lifter system) does mechanical disadvantage/inefficiency create virtual tension that matches or exceeds that generated by a higher absolute load on a barbell?
What's important is magnitude & duration of tension. Load is not always the most reliable variable. Sure there is a minimum amount of tension to move a load, but the operator can always use more tension than what's required (from inefficient movement or antagonistic tension). Time under tension is also important. Most people use number of reps, but actual time under tension can vary wildly for a given number of reps. These principles are why isometric resistance training works.
 

North Coast Miller

More than 2500 posts
Can two unequal loads recruit the same (or the lesser weight recruit/demand more) tension, due simply to differences in leverage?
The answer is a resounding YES.
Not only is this the case, it also effects specific muscle recruitment and core activation. But...this is more the case for upper body work than lower.

When you cantilever a load out away from a support, the shear forces increase but the compressive forces stay the same. A structural engineer could give you the actual values based on load and distance, I am more of a graphic arts person. Some of the plate loading machines like Hammer Strength use this principle to generate more resistance per lb of iron, but it doesn't really effect how it is lifted.

Ballistic movements don't really apply, as the body is positioned to counter the forces being generated.

Since I started my Hobo Strong experiments I now always include upper body exercises that require the load be moved outside the line of support/line of gravity. The difference isn't so much how the load is specifically being manipulated inside that line, so much as how far outside the line it goes and in what direction relative to the trunk - that determines the core muscles that are involuntarily activated.

One can consciously activate core musculature to improve force transfer even with loads inside the line of support, but this is not the same thing really. I'm not sure it is an integral part of KB by nature, there are some exercises that make very little use of this and some more, none of the common lifts really do so to any great degree in my opinion.
 

North Coast Miller

More than 2500 posts
When it comes to straightforward and efficient training, the load is always the most simple and the most effective variable. This is something that I feel should be emphasized.
Absolutely. The load matched to the movement. Whether a given movement disadvantages one or not is almost unimportant in some respects (it effects the specific muscle recruited), the amount of resistance and the power curve are what's important. Some exercises have a bell curve, others a U, and everything in between. But the load (resistance) and TUT are what determines the adaptive response more than any other variables for any given movement.[/QUOTE]

I hesitate to pit the TGU against the overhead squat. I would say the overhead squat demands more mobility and skill than the TGU. It is, per se, the harder exercise. Just that people don't do a certain exercise does not make it harder.
As far as leverages go, the TGU and overhead squat both support the load with the lifter square between gravity and said load. Overhead squat demands more mobility, TGU demands more motor control in the shoulder complex, and there is definitely a knack to keeping the elbow locked/semi-locked throughout. I don't think you can equate them. You can decide which one is more useful for its adaptive response relative to one's goals.

Now if one were to do a TGU with a lot less weight but had to keep the arm out at a 45° angle, now you have some offset loading. The lift will be a lot easier from a lunging standpoint, but the core and shoulder will be taxed severely. 20-25lbs would be brutal.

There are other examples of different leverages you can use - tie a 6 foot cord to a moderate weight KB and other end to something heavy in front of you, about 3 ft off the floor. Now suspend a 5-10lb weight at the midpoint. Commence doing 1 hand rows, but also trying to keep the cord tension such that it is as straight as possible - the midpoint weight is as high as you can get it.

Leverages now demand you pull in two planes (or the midpoint of both), activating a whole different set of muscles from just the unencumbered row. A relatively light load for simple rows and a very light load on the cord combine to require massive tension to complete the move. It also doesn't let off at any point in the lift.

Again, the KB might cause some leverage loading effects esp as the KB gets larger. Sandbags do the same, but really it depends on how you position yourself relative to gravity and the load.
 

Steve Freides

Forum Administrator
Senior Certified Instructor
@Sean M, you've got quite a few assumptions in your post that are likely oversimplifications. There are many variables. StrongFirst principles and practices distill for you what we know works, usually in ways that lead to both greater safety and greater performance. But elite performance in any physical activity necessarily pushes the envelope and engenders more risk. Beginning lifters don't play by the same rules as intermediate lifters, and neither follows the rules of the advanced or elite. A "strength adaptation" can be lifting the same weight without your shoulder hurting - an adaptation may not yield an immediate result of a greater load moved.

Too many variables to be summarized as you're trying to summarize. Maybe read SuperTraining by Siff and Verkhoshansky - it would shed light on some of what you're trying to understand.

-S-
 

Kozushi

More than 2500 posts
Something big I learned here and elsewhere is "specificity". This means you get strong at exactly what you are training, exactly those specific moves in those specific ways. Swinging a kettlebell trains you to swing a kettlebell of a particular weight so many times, but picking up a heavy weight from the ground trains you exactly for this different movement. Carry over is of course a real thing. My S&S training allowed me to pick up 1.5 times my bodyweight right away with no preparatory training, but it didn't get me higher than this. I noticed doing the deadlifts and getting a bit higher with them at 370lbs for reps allowed me to nearly get straight levers on the chinup bar. There was clearly transfer happening from one strength to another. But swings train you to violently swing a weight, this is a kind of strength-speed-endurance training. There are different kinds of muscles - slow, medium, fast - so imagine how differently you train your muscles between deadlifts and swings.

A benchpress is a different movement from an overhead press. I am not at all surprised the benchpressers couldn't overhead press the kettlebell! I guarantee they could bench press the same kettlebell though! It's the direction of the movement that is different here and not the shape of the weight that counts in this case.

TGUs challenge you because of the balance problem. It is one thing to lift heavy weights that are balanced and yet another to lift weights that are unbalanced, called asymmetrical loading. But this too is specificity at work. The TGU trains the TGU movement and it requires a lighter weight than the benchpress. It's just like this.

I still think the hardest question in physical training is not "how do I get to my goals", which can be answered with this or that programme, but rather "what should my goals be?" I think this is the harder question, and the one that isn't asked enough. I can arbitrarily make my goal "to get stronger" and then arbitrarily follow any strength program, or I can ask what my goals should be to myself or someone wiser, and become utterly perplexed!

Indeed deciding if the 300lbs bench pressers or the 40kg TGUers are "stronger" is I think unanswerable. The question "should I train the bench press or the TGU" is likely answerable if I have goals, and my goals are valid if I have a valid reason for having them in the first place!
 
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offwidth

More than 5000 posts
I still think the hardest question in physical training is not "how do I get to my goals", which can be answered with this or that programme, but rather "what should my goals be?" I think this is the harder question,
Indeed.

I find many people lack 'Clarity of Purpose'

And not just in physical pursuits...
 

North Coast Miller

More than 2500 posts
A benchpress is a different movement from an overhead press. I am not at all surprised the benchpressers couldn't overhead press the kettlebell! I guarantee they could bench press the same kettlebell though! It's the direction of the movement that is different here and not the shape of the weight that counts in this case.
Here's a good experiment w/ kettlebell. Set up for a floor press and execute with the hand perpendicular to the body.

Then externally rotate the hand so the load is furthest away from the shoulder and press again. Changing the bending moment changes the shear force/resistance.
 

jef

I am a student of strength.
Certified Instructor
I'm reminded of the quote from Pavel somewhere about him challenging 300-pound bench pressers to one-arm press a 40kg at a strength convention, which many couldn't do, even with assistance getting it into the rack position.
If it is the challenge they did at a the Arnold's convention (mentioned in Beyond bodybuilding, if I recall properly), most body-builders who were more interested by appearance than strength could not press it. Most powerlifters who were more interested by strength than appearance could.
So it seems that 300-pound bench presser did press the 40kg.
 
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