muscle memory
Shugart: What causes the phenomenon of muscle memory?
Thibaudeau: Hard to pinpoint one cause. Fascia stretching is one thing. When a
muscle is hypertrophied and stays large for a while, it does stretch its
envelope (the fascia). When you stop training, muscle will atrophy (lose size)
but fascia will take a much longer time to get back to its original tightness.
As long as it's still slightly stretched, muscle growth is facilitated.
This is why if you've been muscular for a long time you'll regain the muscle
faster (because the stretch is more significant). It also means that the longer
you wait before re-training, the more of the "plasticity facilitation" you'll
lose.
For example, if you stop training for 10 years, chances are that you'll regain
the muscle at a much slower pace than if you stopped training for only 2 years:
the fascia doesn't have time to tighten up completely with the shorter time
period.
Some also believe that carrying extra muscle size for a while gets the body
"used to" that state. The body comes to accept it as normal. It's much easier
for the body to get back to a normal state than it is to go beyond it. So
regaining muscle (going back to a once-normal state) is more "comfortable" than
going to brand new levels of muscularity (exceeding what your body perceives as
normal).
Shugart: What about the myostatin aspect? What's the theory behind that?
Thibaudeau: Myostatin is the gene that limits muscle growth. The more of it you
have, the harder it is to grow muscle. It's been suggested that spending a lot
of time in a muscular state lowers myostatin levels. When you stop training you
lose some muscle, but myostatin levels stay low, which makes it easier to pile
on muscle once you get back into it.
Whatever the cause of muscle memory might be, we can say for sure that:
1. The more muscle you had, the easier it'll be to become big again upon
retraining.
2. The longer you've been carrying extra muscle, the more pronounced and the
longer lasting the "muscle memory" will be.
3. The longer you wait before training again, the less of an effect on re-growth
you'll have.