Joe Weider’s Muscle Confusion Principle suggests regularly changing your weight training routine to make your muscles adapt to a different type of stimulus. This can encourage continued size and strength gains.
Now there’s evidence your muscle cells have a memory of training. A study published in the journal Frontiers in Physiology found that muscles remember being built and strengthened, and can adapt more quickly when you return to the weight room after a long absence.
When muscles are growing, new nuclei are added, the part of a muscle cell that helps build and maintain muscle fibers. Using advanced laboratory techniques, researchers found that these nuclei don’t disappear when muscle shrinks from disuse. In fact, they allow greater and faster growth once strength training resumes.