jminis said:
I feel the same here. I never said you can change the shape of the muscle nor do I believe one can do so, I'm simply saying by doing certain exercises from various angles you can work certain parts of the muscle (aka activate different bundles of muscle fiber) They don't all fire 100% every lift depending on the angle the muscle is hit dictates which are used more.
NONE of us was saying this....
maybe the source of confusion lies here:
jjjjd said:
jminis, i would love to know how any exercise can emphasize the "lower lats" since the lats run as one muscle fiber. how does one preferentially emphasize the lower portion of a muscle fiber?
seems pretty clear jjjd doesn't know the difference between a muscle, a muscle fiber, and a fiber bundle - not to single him out, I'm sure most people don't.
jjjd - you are right in this: one cannot "preferentially emphasise" *part* of a muscle fiber - either the fiber is recruited (that is, fully engaged) by a movement or it isn't. But take a look at that picture I posted of the lat: all those lines in the muscle (striations) are bundles of fibers. That's what muscles are: multiple bundles of multiple fibers.
Notice the fan shape to the muscle: this is due to the bundles originating over such a wide area. Now, consider that each fiber can only pull IN A STRAIGHT LINE, and you can see that the lower fibers (the bundles that originate near the pelvis) pull along a different line than the upper fibers, the ones that originate @ the level of the shoulder blade.
See? That's why different exercises, grips, etc. can target different regions of a muscle. The line you pull along determines which bundles of fibers carry the load...and are therefore preferentially recruited. This, along with injury-prevention, is why proper form is so important.
This is not brotelligence - this is science (no disrespect intended to the wisdom / experience of real lifters - scientists can fall victim to their own forms of brotelligence). Any decent anatomy / physiology textbook will tell you the same - you can pick one up used for relatively cheap at a local college bookstore. With these facts, and some thought, the whole issue of the "lower lats" should clear itself up.
That said, I'm smart enough to know that there are people smarter / better informed than me - so once again, I stand ready to be corrected.
I have to thank
cobain67 for the initial question, and
jjjd for the spur, 'cause it got me off my ass & back into my textbooks (it's been a few years). It also got me looking into texts on exercise physiology: in case anyone cares, here are a few I found on Amazon:
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*whew*
once again, I hope this helps!