Eccentric training, also known as negative training, is a technique that allows you to push your muscles past their normal point of failure. Eccentric movements are performed involving lengthening of the muscle fibers. This type of negative training is more demanding on the muscles, therefore they are fatigued a lot further than is possible during concentric movement. Stressing the muscle, while it is lengthened, actually damages the micro-fibers of the muscle to such an extent that there is an increased potential for greater stimulation and growth. Contractions that permit the muscle to shorten are concentric contractions, for instance while lifting a weight. Eccentric contractions stress the muscle while it is lengthened, e.g. while lowering a weight.
The key to understanding the negative workout lies in this view of how individual motor units or the muscles are recruited: Because some motor units are turned off while a weight is lowered, a decreased number of motor units are holding the weight. The active motor units are then exposed to a greater level of tension, which now provides an opportunity for greater growth stimulus. For example: Suppose you are using a muscle composed of 10 motor units to lift a weight of 100 lbs. When you lift the weight, all the motor units participate so each motor unit is exposed to 100 pounds of tension. You lower the weight by turning off some motor units; lets say you turn off 3, this leaves 7 motor units to lower the weight under control. Because there are now fewer motor units supporting the weight, each of the remaining active motor units is exposed to more tension resulting in muscle hypertrophy (i.e. increase in the size of the muscle cells). Because each motor unit is exposed to greater tension during the eccentric portion of the lift greater growth stimulus results. Clearly, performing negatives can lead to muscular growth more quickly than performing concentric or isometric repetitions. However, you must not perform negatives all the time.
There are different methods for eccentric training. The first method is: Negatives Only. This is a situation where a full workout session is dedicated to performing only negative phases of a specific exercise. This method can be useful for building up strength or for blasting through a plateau.
The second method of Eccentric Training is: Extra Eccentric Reps or Forced Negatives. For this, a standard set of repetitions is performed and when concentric failure is reached a partner lifts the weight for you. You perform only the part of the weight training phase that involves lengthening while your partner performs the concentric (lifting) part of this exercise. This action is repeated for the desired number of reps. This is usually repeated 2-4 times, or until the muscles are fatigued.
The way to perform an eccentric rep is to add 40% more weight onto what you would normally do for that exercise. For example: On the bench press if you can perform 8 reps at 225 lbs, you would put 360 pounds on the bar. To start, have your training partner hand off the weight to you, then you would slowly lower the weight. As a general rule of thumb you would take 4-5seconds to lower it (sometimes up to 10 seconds depending on your program). Once the weight has been lowered your partner would then lift it back up for you.
WARNING! Don’t go overboard with eccentric training. Because it does cause more damage to skeletal muscle than concentric or isometric training, it requires more rest and recovery time. Performing negatives excessively can lead to “over-training”. Keep in mind that if negatives are not performed properly you would be risking potential damage to connective tissues and muscles by placing them under an excessive load. These potential problems can be avoided by not performing negatives at every training session, or at the very least, changing the kind of negative training from what you used during your previous workout. By safely incorporating eccentric training into your current training program you create greater overload and create new muscle growth resulting in greater gains thus getting BIGGER! Above all, work with a reputable, certified physical trainer.