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im not sayin concentric contractions are the most important for growth, nor am i sayin negatives are, i really believe both are needed and together work very well, my belief is like lat's in a controlled negative (2 sec or so), and an explosive positive.
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I would say that the negatives are most important for growth. Both is better, I think (based on the research I've read), but given one or the other, I'll take the eccentrics only. Luckily, I don't have to make this choice.
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i am well aware that in negatives there is more tension on the ACTIVE muscle fibers, but less are being recruited, this would lead to greater hypertrophy in the fibers where the tension is applied during the negative but what about those fibers in which there is no tension during the negative?....
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Indeed. That's why taking a set to negative failure (ala a DOGGCRAPP-style hold) can be very effective (but a great way to overtrain).
There is some research (this phenomenon is difficult to study, especially in himans) showing that eccentric movements will elicit a reversal of Henneman's size principle (e.g., see Nardone et al.), such that type II's are recruited (technically they are fibers of the higher threshold units) before (or at lower forces) during negatives than if the same fibers are monitored during concentric contractions. There is also some evidence (EMG's in olympic lifters and motor unit measurements in cats shaking their paws) that very quick, ballistic kind of movements can also cause this kind of reversal. My guess is that the increase in type IIB fiber percentage was due in part to their preferential recruitment during the training (duh!), which may have been greater at a faster ecc. speed. (FYI, there is data demonstrating faster contractile properties in human hand muscle after a balistic type training program, so this study is not out in left field COMPLETELY)
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to me it is 8 great reps vs. 5 good reps
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I aggree with your example completely. But, in the case of this study
--they compared reps that probably took just over 1/2 second with those lasting 3-4 seconds!!! This study is not very relavant in that sense to a discussion of 3 seconds vs. 8 second. In fact, I would say this study suggests that a 3 second eccentric is too slow (not really saying this though b/c the study has so many other differences to what is done in the gym.)
--I don't put a whole lot of stock in a study where one of the experiemental training groups (one that actully spend 6 times longer training d/t the slower speed) than the other exp. group. 10 weeks and no training effect?... Huh?...
--Where is the muscle fiber data?... This is what we really want.
-- Their trainees performed no concentric contractions.
--Contractions were maximal, which is not the case during everyday lifting unless you employ forced negatives.
My point is that this study is nifty - and sets up some interesting research down the road - but it is only one study and one that has poor external validity (applicability) to real world bodybuilding.
I must make note that I have not read the entire study. I have read too many studies where the abstract was not representative of the data presented in the paper. I'll try to ge a hold of it and report back if I do.
Magoo, I'm with ya, man. I train just as you describe, for the reasons you describe. I just don't think this study is a good way to justify it.
-Randy