A new study out of Finland has proven the indisputable value of training with heavy eccentric movements. Scientists examined two groups of trained lifters over a period of 10 weeks. One group trained in a traditional bodybuilding style. The second group used loads that were 40 percent heavier than the first group, and only for negative reps. After performing slow negatives, they then had help pushing the weigh through the positive portion of the rep.
After 10 weeks, both groups had added the same amount of muscle mass, but the negative group became significantly stronger. Interestingly, this strength increase only appeared after five weeks of the protocol. The authors of the study felt that this type of training increased muscle activation and possibly other beneficial mechanisms that were not yet fully understood.