I just read this fascinating article about maintaining and building upon your muscle strength.
Article from Yoga Journal, “The Science of Strengthening” —
In order to help your students build strength, it helps to understand how, and when, human bodies accomplish this task. The foundation of understanding the process is the fact that muscles are constantly being remodeled according to the demands being placed on them. In other words, they accommodate to exactly the load that you place on them in your regular activities. For example, if you regularly lift a 15-pound bag of groceries or dog food or laundry, your lifting muscles, including the biceps on the front of your upper arm, will be just that strong. If, on Monday, you decide to work the biceps by lifting a 20-pound dumbbell ten times, your body will immediately start remodeling the biceps. I call this remodeling process “the 48-hour rule,” which means that in the first 24 hours after you’ve worked a muscle, the old structure, which could lift 15 pounds, will be taken apart; in the next 24 hours, the new structure, which can lift 20 pounds, will be built. If you lift the 20-pounder again on Wednesday, Friday, and Monday—about every 48 hours—your body will maintain the strength. If you don’t lift the 20-pound or even the 15-pound bag again for two weeks, your body will have begun to decondition the muscle significantly.
Now let’s apply the 48-hour rule to yoga. If your student only practices once a week or every other week—the days she comes to class—that’s not often enough to maintain strength, let alone build it. She’s likely to feel frustrated with her lack of progress and may become discouraged or overwhelmed. I therefore encourage students, as part of developing their home practice, to work on their “problem areas” three times each week, in a way that gently challenges them. They’re usually pleasantly surprised when they come to class and a previously difficult or impossible pose is easier.