eccentric/concentric movement speed, how important is it?

I was wondering how important is the speed in which the weight is lifted and lowered, i.e concentric and eccentric motions.
I've been reading about it. There are many people claiming that it is very important, but I don't see anyone applying it.
I mean there are so many videos on the internet of Arnie and Ronnie, as well as other reputable body builders, they all lift explosively in all of the videos I've seen.
Is it better to lift in a controlled motion, let's say 3 second lowering the weight, 2 seconds lifting the weight as opposed to normal lifting, which is lifting the weight semi-fast, and lowering the weight very quickly, in a second or less with no regard to the eccentric (lowering) movement.

That's how most if not all of the people I've seen train (including me). Let's say you're benching 180, how is it better to do 5-6 reps in a controlled motion, as opposed to doing 8 reps in a normal "fast" lifting.
 
the concentric phase should be done as quickly as possible, it makes you recruit more motor units in your muscles.. IE, you will be using "more" of your muscles.
 
Back
Top