Though there scientifically is no such thing is muscle memory, good job! Keep it up. It's inspiring to hear everyone in here.
Actually, yes there is.
First there is the neural part. Your body must learn how to work under the stress of maximum weights. When you start training back, you dont need to break trough the walls you went trough before
Secondly, your body's nitrogen retention has been at higher levels before. So you are in a state of imbalance. As long as its not TO long , you'll be getting that muscle back more easy thanks to higher nitrogen retention then compared when you were at this level before
example : bench press
certain point of time : weight x, your body's N-retention : y
4 months later : weight X+15kg, your body's N-retention : Y+a
3 months without training : weight : X, your body's nitrogen retention : between y and Y+a
SO, you will raise in weight pushed and muscle build faster then you did before.
I had a simular thing happening.
It took me 8 months to get from 4x110kg benchpress to 11x110kg bench press, on december 17th
Then i had a rotator injury, and couldnt do any excercise for chest and shoulders for 4 weeks, and trained very low weight for another 2, low as in 35%theoretic 1rm
It was down to 5 reps at 6 februari when i could finally train decent.
Last fryday, it was at 11 again.