By "eccentrics" I mean the eccentric/negative phase of a movement. I know that some bodybuilders emphasize it for different reasons, but how about for strength gain?
If you subscribe to the Westside Barbell teachings, eccentrics only contribute to muscle soreness...they do increase hypertrophy however. Per Louie Simmon's claims, anyone who has focused on negatives in an attempt to make gains has made backwards progress.
I will say that some of my earlier progressive overload programs that I ran out of Powerlifting USA included negative for the bench...it all seemed to come together at that point in time nicely. I'd guess that it really depends on what point you are at in your training. If you're just starting off, negatives might be helpful but I'd use them sparingly.
Finally, negatives or concentrating on the eccentric is not something I have done for years. On any primary lift I control the weight. I don't bring the bar down any slower than I feel is necessary to command the bar. On any type of supplemental or accessory work (i.e. triceps), I definitely do not put any emphasis on the negative.
Eccentic muscle action is incredibly important. Concentric only movements do not develop the stretch reflex. There is no way in hell you will be able to move heavy weights without teaching your muscles how to develop and utilize kinetic energy accumulated through the stretch shortening cycle. I am not saying doing negatives is a good thing, because they will not make you stronger. I am talking about maximizing force production using optimal (i.e. fast as shit) eccentrics.
Also, your muscles have mechanoreceptors that send signals to shut down contraction when there is too much stretch/load/pressure in a muscle. Fast eccentrics train these recpceptors to not engage so that the above mentioned kinetic energy can be used in the development of force.
Slow negatives will make you bigger because they do significantly more damage to muscle tissue than concentric and isometric muscle actions. This is not the goal for strength/power athletes. The goal is increased inter/intra-muscular coordination so that heavier weights can be lifted more efficiently. Recovery is vital so that more/heavier work can be done more often. Negatives take the standard rule of 72 hours between intense workouts and pisses all over it.
Every method has its place in training, depending on your own goals and weaknesses, but using negatives on a regular basis or using just concentric only exercises on a regular basis is not the best idea.
I barely understood any of that. Thanks. I feel stupid now.
I don't do a ton of negatives. I've done them on bench more so that I can get the 'mental' feel of a heavier weight. For me it's the bench equivalent of a walk out; more of a mental exercise.
I've also done them on pullups when I couldn't do even one. They definately helped there.
What Storm said, but I'll add a little.Let's take it to the ridiculous extreme. Don't do any negative at all. Have people place the bar on your chest. Let them take it down on the deadlift. Start from the bottom in the squat.
You see what i mean. You're going to have to do the negative, without it you're changing the lift. And you're not going to find such dedicated training partners to help you do it without them.
I know I'm being silly by illustrating this, I just mean to show how you'd change the entire lift.