I fail to understand why on earth negatives would work for bodybuilding purposes (or even strength training purposes for that matter).
The muscle is stimulated only through the concentric range and determining how stimulated it gets is determined by how many muscle fibres are recruited to perform the concentric action. This is why half reps are not effective either - you need to recruit as much muscle fibres as possible to stimulate the muscle to its fullest. No amount of weight will help you on the eccentric portion of the rep and nobody ever got bigger or stronger by performing negative reps with a spotter. You don't see WSM competitiors doing negatives in the gym to help with their strength - why would it help anyone elses?
Here's where you're fundamentally wrong, in my humble opinion.
Or lets say that you and I are of opposing opinions?
I believe, after seeing studies and talking to a few sports scientists, that it is only during the eccentric phase that there is significant hypertrophic stimuli.
Obviously, there are a few other things that dictate
strength (eg neuromuscular pathway signal strength), but for a bodybuilder, IMO, it does not make any sense to do slow concentric repetitions.
The focus should be on the eccentric portion of the repetition.
I've seen a study in which a leg press where used, concentric and eccentric versions of the leg press where performed.
Only in the eccentric test group where there significant acute anabolic signals.
I respect your opinion, but I totally disagree.
As far as eccentric training goes though:
It could probably be used by anyone.
And just like Magoo stated, beginners can probably get away with using a higher percentage.
But the problem for inexperienced lifters, is that there's a big chance that they will increase the weights used the whole time and do too many sets and too much volume.
Maybe this is what wes was referring to, and then I think he's right. You need to be experienced, or have a very good layout and follow it.
Or optimally, have someone guiding you. Then eccentrics are an awesome tool IMO.
FWIW, I think eccentric reverse hypers (Lay down on a lateral extension board and have your buddy pull you down) is an excellent rehab/prehab excersise.
Just as eccentric crunches can be a great alternative for those who wants to do crunches but have an hurting lower back or hip.
When implementing eccentrics:
* control total volume
* don't do them every week. use it moderatly, be aware of its effect.
* why not try focusing on the eccentric phase in regular sets for a few weeks. see what happens.
Finally, a short note on what you wrote about half reps:
This is why half reps are not effective either - you need to recruit as much muscle fibres as possible to stimulate the muscle to its fullest.
I'm not sure you understand how muscle fibers work.
They're much like lamps.
Either they work full force. Or they don't.
Which mean that in order to work all muscle fibers, we need to lift as heavy weights as possible.
This is one reason why eccentrics are great. They allow us to recruit more muscle fibers than we normally do during a conventional set.
There's something called the "Hennemann's size principle" which means that the muscle will recruit only the muscle fibers needed for the work it has to do.
So in effect, it means that the strongest fibers will be resting until we give them hell.
The slow twitch fibers are constantly working, even in our daily life.
