At the close of the Thirty Paintings in Thirty Day Challenge, there was a death in my family. A wonderful person that touched the lives of her family so that they arrived from great distances. I lost only two but two full days of painting. Today, I tried a warm up watercolor and felt like a beginner. I attempted to push along my silk painting project and still felt out of my element. So, I decided to modify an oil painting I wasn't fully happy with. That painting is now in the trash.
Here is the data on Muscle Loss in Sports:
An article by Ben Greenfield (link): "How Fast Do You Get Out of Shape?" reports that muscles can atrophy (muscles get smaller) and muscle fiber type conversion (change what they are made of) can occur in as little as 72 hours. The amount of change or loss depends on how often the muscle is used. The better the shape the muscle was in before being unused, the slower it will atrophy.
Anders Ericsson's (link) research is the basis for the 10,000 hour rule (or ten year rule) which suggests that proficiency in any field requires this amount of deliberate practice time. I imagine this 10,000 hour proficiency would be similar to a trained muscle in thinking about disuse atrophy.
Cross your fingers!