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(quadancer @ Nov. 22 2007,10:00)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">Just a bit of blather (like that word, Lol?) in understanding ecc/con.
A muscle does not "PUSH"! It can only PULL.
Therefore, when it pulls, it "concentrates", "condenses", "compresses" in a way.
When you bench, the triceps and pecs pull the back of the forearms to extend the arms, not push them. So "pushing" the load up is concentric. When you lower the weight (folding the arm), it "extends" the muscles and is therefore eccentric.
Inversely, a bicep curl is concentric when the arm is pulled towards you (folded), as the bicep is compressing...in a sense.
And opposingly, is eccentric when the weight is dropped, as the bicep extends.
Did I get it right guys, or confuse the issue further?
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Perfect way to describe it.
Negatives or eccentrics are another way of saying "loaded stretch" as Quad described so clearly. They can be done with enormous loads, but spotters/safety is critical.