Negatives / Eccentrics
There are two variations possible. In the first, you take a heavy load that you cannot perform any repetition at all on your own. Let your training partner help you bring the weight to the top. Then, he lets go of the bar and you fight with all your strength against it and slowly lower the weight to the bottom of the range of motion.
In the second variation you complete (as in forced repetitions) as many reps as you can. But then your partner helps you in a strong fashion bring the weight quickly back to the top point, from where you lower it as slowly as possible on your own again.
Both variants should be used for three to four repetitions, because fatigue sets in very quickly in this method.
Especially suitable and popular for negative repetitions are all chest, biceps or shoulder exercises. In the latter, only upright-rows are not eligible. Also very good are all forms of lat pulldowns and chin-ups. Especially with pull-ups, you can also use negative repetitions very well without a partner. You can just jump up into the maximum contracted position and slowly let yourself down on your own. In leg and rowing exercises for the back, however, negative repetitions are ruled out.
The slow lowering of the weight makes mistakes almost impossible here. However, the training weight should not be too high. It has to remain controllable.