There are two components to any lift: the actual lifting component, which is known as the concentric contraction, and a lowering component, which is known as the eccentric contraction. During a barbell curl, for example, the curling portion of the lift is the concentric component, while lowering the weight constitutes the eccentric component.
Most of us are stronger on the eccentric portion of a lift since we're working with gravity, not against it, and our muscles don't have to work as hard when we're lowering a weight. In order to make a lift difficult during both the lowering and lifting portions, we have to apply force to the eccentric, or negative, component.
Applying force to a weight as it's being lowered increases the number of muscle fibers you recruit, and also increases the tension on your working muscles. Together, these two factors lead to growth.
Project Mass Trainer Eccentric Training
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During the hypertrophy workouts of Project Mass—particularly in the third microcycle of each phase—you can utilize this technique when you want or need some extra toughness. It's an especially great method to use when the workout protocol asks you to go to failure.
To perform eccentric training, or forced negative training, you'll need a buddy. Have that buddy push resistance to your weight as you're lowering under control. For example, do a barbell curl and have your partner press down on the bar as you lower it. Your job as the lifter is to resist the extra weight from your partner and lower the barbell slowly.
Resisting the weight as you move the load down makes your muscles work harder throughout the entire lift. Be prepared to feel a lot of tightness and swelling. That's good! You want to feel all that blood and lactic-acid buildup.
If you don't have a buddy, you can still use this technique with certain exercises. You can use dumbbells and curl with one arm, for example. On the eccentric portion of the curl, push your own arm down with your free hand, and resist the extra force when lowering the weight.