eccentric training

Eccentric Training Stimulates Muscle Growth

The recent studies found that eccentric-only training led to an average muscle size gain of 6.6% over 10 weeks while a concentric-only program led to gains of 5%. While the difference may not seem to be huge, any bodybuilder who knows his stuff understands that 2% more muscle over a 10 week period can be visually important, especially in the long run. These results are backed by another recent study (Farthing and Chilibeck 2003), which concluded that eccentric training resulted in greater hypertrophy than concentric training.

One recent study even found accentuated eccentric training to cause 19% more muscle growth than traditional strength training over 11 weeks! Another study concluded that eccentric muscle actions are a necessary stimulus for muscle hypertrophy.

Why is eccentric training effective?

Eccentric training allows one to stimulate greater strength and size gains than pure concentric training. Why is that? There are five major reasons why:

  1. There is a greater neural adaptation to eccentric training than to concentric training.
  2. There is a more important force output produced during a maximal eccentric action (greater overload) because you can use a higher external load.
  3. There is a higher level of stress per motor unit during eccentric work. Less motor units are recruited during the eccentric portion of a movement, thus each of the recruited motor units receives much more stimulation. Furthermore, since the nervous systems seems to recruit less motor units during a maximal eccentric action, the potential for improvement could be greater than with maximal concentric action.
  4. There is some evidence that maximal eccentric actions will preferably recruit fast twitch muscle fibers, which are more responsive to muscle growth and strengthening. In fact, eccentric training may stimulate an evolution towards a faster contractile profile.
  5. Most of the micro-trauma to the muscle cells incurred during training is a result of the eccentric action. It has been established that this micro-trauma acts as the signal to start the muscle adaptation process.