If you’ve stopped making gains in the weight room, it’s time to get scientific to smash through the plateau. Don’t worry, we’ve crunched all the data for you
I’ve always wanted to know what causes individuals to plateau when they were able to make gains so readily in their earlier days of training. That mechanism has to do with a type of cell in the body known as satellite cells. You’re about to learn what they are and how you can activate them through optimal eccentric loading. The result is the ability to smash through the dreaded plateau.
We can lift a weight concentrically (the lifting phase) and eccentrically (the lowering phase). Scientists have found that the eccentric and concentric phases of a lift trigger different mechanisms of muscle growth. When you lift weight concentrically, you produce greater metabolic stress, and this can lead to muscle growth. However, research has shown that when you lengthen the muscle eccentrically, you increase protein synthesis more than a concentric contraction.
Why is this the case? Eccentric contractions release a chemical called phosphatidic acid. If you inhibit it, you prevent the muscle from growing. In fact, our lab recently conducted a study where we found that just bathing muscle cells in phosphatidic acid made them increase in protein synthesis. If you give individuals phosphatidic acid, it increases muscle growth. This indicates the importance of lengthening the muscle for the purposes of hypertrophy.
One of the primary ways eccentric contractions work is via the activation of satellite cells, which are located on the outside of the muscle. They are a unique group of cells that respond to damage by turning into immature muscle fibers that move to the damaged area where they fuse to muscle. The result is increased muscle fiber size and the addition of the satellite cells’ nucleus to the muscle.
The latter is critical, as nuclei in the muscle are primarily responsible for stimulating skeletal muscle protein synthesis/growth. The more nuclei you have, the greater your growth potential. In fact, research shows that individuals who plateau in their training are those who cannot adequately activate satellite cells. To tap into this critical cell population for growth, you have to maximize eccentric loading.
Maximal eccentric lifting stimulates more muscle growth than maximal concentric contractions. Most people want to ‘slow’ the eccentric contraction down to create more muscle growth. While logical, it actually does not work. How can emphasizing eccentric contractions with a slow cadence not create more growth and activate more muscle cells? Research shows that faster speed eccentric contractions result in a release of more growth factors, more satellite cells and greater protein synthesis than slow-speed eccentric contractions.
Muscle is made of actin and myosin.
When they bind to each other or form a cross-bridge, they produce the tension we know as contraction. We have numerous actin and myosin molecules. The more cross-bridges that are formed by actin and myosin, the less tension any one cross-bridge will have to support. The lower the tension on any cross-bridge, the lower the muscle damage will be.
The major downfall to slowing down your contractions to emphasize the eccentric contraction is that your body has more time to form cross-bridges. The result is less damage, lower protein synthesis and less growth. Control the eccentric contraction, but do not slow it. For example, if you’re training arms, take only one to two seconds to lower the weight.
One key point that needs to be hammered home is that you can lift more weight eccentrically than you can concentrically. When studies have taken the 1RM or percentage of the 1RM for concentric contractions and had individuals lift it eccentrically, they found no differences in muscle growth between contractions. Some studies indicated an advantage for the concentric contractions under these conditions. Thus, if you are emphasizing the eccentric contraction with the same weight you are using for concentric contractions, you will not add any benefit over the concentric contraction.
However, we are generally limited in a lift by how much we can lift on the up phase, not the down phase. This leaves us with a problem in which we are not optimizing the full growth potential of the lift. There are a number of ways to increase the eccentric load. The classic way is to use assisted negative reps. Assisted negative reps are where you lift the weight, and on the way down your partner presses down on the weight to increase the eccentric load. A second way is to lift a weight with two limbs and lower with one. For example, if you are doing hamstring curls with two legs on the way up, you can lower with only one leg, thereby overloading the eccentric phase of the lift.
The reason plateaus are reached is because individuals are no longer able to activate satellite cells. To overload on the eccentric portion of the lift, you should have a controlled but relatively short eccentric phase of a lift (one to three seconds maximum). It’s critical to realize that slow contractions may actually impair muscle growth.
Assisted negative repetitions can optimize protein synthesis and muscle growth. One final point is that you will need to acclimate to this method over time, as it can lead to substantial muscle damage. Perhaps use it once per week for the muscle that needs the most work.