Something that gets discussed in strength-training circles, but never fully explored, is the notion of movement efficiency.

Efficiency could be described as the ability to generate the maximum amount of force with a minimum of effort. Strength training will make you more efficient--it's part of getting stronger--but only up to a point.

Free-weight proponents, like me, often like to say that these types of exercises resemble real-life and real-athletic movements: a barbell back squat resembles getting up from a chair, for example.

But does it really? When you perform a back squat, you've got a loaded barbell on your shoulders, which significantly raises you center of gravity and necessitates a maximally symmetrical posture, and a carefully-aligned back, to ensure the safety of the spine. You also perform the exercise on a precisely flat floor, something that doesn't exist in nature.

No human being I know gets up from a chair in this manner; rather, they turn and twist, their heads drop forward and down, their spine rounds. Think of the way you get out of a car seat, with its offset stance, the head-duck the proceeds standing so you don't whack your head on the car's ceiling, and the twist that initiates the move as you turn from your seat, and you'll immediately notice that it's a movement for which there is no real gym analog. It's purely a 'life' move.

There's really no problem with that; it's just that 'real life' demands a far greater range of types of movement than is offered by the gym. And that gym movements like lunges, rows, squats, presses, and planks don't really, literally prepare you to move better in life. They're just as close an approximation as we can make using barbells and dumbbells.

I'm not really trained in kettlebells, but I'm intrigued by them in part because the curvilinear, power-driven movements in kettlebell work seem to get a little closer to 'real life' moves than the sheer up-and-downyness of barbells and dumbbells.

As to the question of efficiency--and again, I speak as a fan of the weights, but also someone who is aware of some of their limitations--some strength-training moves demand maximum efficiency; others ask for a kind of controlled inefficiency.

Compare a reverse-grip barbell curl to a hang clean. Both movements accomplish the same thing: the bar travels from waist level to shoulder height. The first, however, imposes all kinds of limitations: you can't swing your body. You move in a way that maximizes motion at the elbow joint and minimizes it elsewhere. Your spine doesn't move from an up-and-down, neutral posture. It's a highly artificial movement--something no one who didn't care about building his biceps would ever choose to do.

The hang clean is the maximally efficient means to get the bar to shoulder height: you call on your largest muscles, as well as a swinging, arcing, indirect movement, to move the bar. You maximize momentum. You use power and explosiveness, not relying only on a single muscle group to get the weight up (and of course I realize, as has been written about extensively elsewhere, that no isolation move really isolates).

I'm interested, as you can see, in this idea: it seems that a strength-training routine should emphasize movements which teach efficiency and minimize exercises that cut against that grain. One purpose of strength training, of course, is to teach us to move better.

If I'm putting this model together right--and I'm not sure I've read about this anywhere else--it seems like all power movements--cleans, snatches, push-presses--shoot for maximally efficiency. Deadlifts, and bench presses probably do too. I think squats are a little off for most people because you probably can generate more force by leaning too far forward--something you see people doing naturally when they're squatting too heavily anyway. Regular overhead presses and all isolation movements strike me as pretty far off the beam: a caveman would never choose not to use body english to lift a heavy rock overhead; he doesn't care about stressing his deltoids; he just wants to move the damn rock.

I think there's more unpacking on this question. Any thought from my geekishly-inclined readers?