That's a succinct summary of the physics of barbell training.
Hello Mark,
Am I being correct if I summarize Starting Strength as;
1) The most efficient way of lifting a weight is to move it along the shortest straight line in the direction opposite to the opposing force. Given the mass to be moved, opposing force, the energy available to lift the mass and the final configuration of the system remain constant.
2) The strongest muscles in the kinematic chain for a given movement should be provided with the largest leverage and range of motion
?
I ask this just to check if I understood the fundamentals correctly.
That's a succinct summary of the physics of barbell training.
...."and drink milk" should be added at the end
And the goal, of course, is to develop the ability to generate zero net force on ever more massive objects. Awesome, huh?
Fucking physics.
Zero net force? That would only apply in isometric exercises. If you are moving a barbell through space there is positive net force. Actually hold on that's not even true. If the barbell is moving at constant velocity there is no zero net force you are correct there. But then you had to accelerate it to move it from rest in the first place, back to net force production. Gah, this is why I never liked the use of the classical physics definition of force in the context of exercise.
Er, don't you mean zero net work? Since even a fast lowering of a deadlift is still slower than just dropping the thing, there is net force of at least some fractional amount on a barbell throughout the ROM in every lift, even if the bar ends up at the same position as when it starts(zero work). There are two exceptions--a failed squat rep, which ends at a lower potential energy than when it started(negative work), and deadlifting with octagonal plates, because the barbell has some horizontal displacement on every rep.
So if your gym bought shitty octagonal plates, you should thank the gym owner for letting you do some actual work.
Don't wander off, John...
So what is the system boundary here? If the system under discussion is the lifter plus the earth then yes, you are correct there is net zero force (actually that's not even true). If the system is the lifter only, and this is the only system that makes sense to me, then there is net positive force because you are applying positive acceleration on both the concentric and eccentric portion of this lift, it's just that gravity applies more than you do during the eccentric portion.
This is analogous to the question of whether abiogenesis breaks the second law of thermodynamics. It seems to if the earth is viewed as a closed system, but when you realize the sun is pumping trillions of joules of energy into the earth you realize it is not. You have to define your system boundary.
Regardless, the classical mechanics definition of force is a strange one in the context of lifting.