Negatives recruit different fibers?

[innermusic]

Do negatives actually recruit different fibers? Is it just that negatives cause greater muscle recruitment and therefore more microtrauma, or are different actual fibers involved for concentric/eccentric movements?

 

[jvroig]

Same fibers; with sufficient load, all fibers are already recruited, there isn't any left for negatives to exclusively recruit.

Greater load in the negatives allows for more microtrauma and, most importantly, continuation of progressive loading, and since it's focused on the eccentric, Type II fibers are recruited faster. In other words = good for hypertrophy

 

[thehamma]

I actually had the same question.  In the thread I started in HST Dan posted

Quote[/b] ]As JV said recruitment order is set for the most part, there are two generally accepted exceptions to the standard sequence, one is during eccentrics and the second is during occlusion. Both of these recruit type II faster than a normal repetitive or isometric contraction scenario.

I'd be interested on hearing a little more on this topic. Also, what is occlusion?

thehamma

 

[jvroig]

Occlusion simply means blockage or obstruction. Occlusion here refers to blood occlusion in the muscle worked; occlusion studies (BB related of course) found good results. You can imitate this by training with a tourniquet   For normal folk, however, this is what is tried to accomplish when we do highrep sets (drops sets and other metabolllic work sets) - the high reps keep the blood pumped out from the area, more or less (yeah, so ditch the tourniquet)

 

[thehamma]

Quote[/b] ]recruitment order is set for the most part, there are two generally accepted exceptions to the standard sequence, one is during eccentrics and the second is during occlusion. Both of these recruit type II faster than a normal repetitive or isometric contraction scenario.

I thought this implies that there is a difference in recruitment between negative and positive contractions?

thehamma

 

[innermusic]

Quote[/b] (thehamma @ Oct. 20 2005,5:21)]

Quote[/b] ]recruitment order is set for the most part, there are two generally accepted exceptions to the standard sequence, one is during eccentrics and the second is during occlusion. Both of these recruit type II faster than a normal repetitive or isometric contraction scenario.

I thought this implies that there is a difference in recruitment between negative and positive contractions?
thehamma

That's what it sounds like to me as well. Here's a study I've since found since my original post:
J Physiol. 1989 Feb;409:451-71. Related Articles, Links Selective recruitment of high-threshold human motor units during voluntary isotonic lengthening of active muscles.
Nardone A, Romano C, Schieppati M.
Istituto di Fisiologia Umana II, Universita degli Studi di Milano, Italy.

The study seems to indicate type ii fibers are recruited preferentially during eccentric portion of various exercises.

 

[thehamma]

Come on fellas, this is an interesting topic which I know a lot of you have plenty answers for. Just because its in General Training I don't want this one to get lost in the shuffle.


thehamma