So happy to have a day to sleep in, and a day to rest! While I feel a little guilty doing so, it is important because recovery is the only time you can actually build muscle.
- Adequate rest between workouts - It is very important to incorporate "rest days" into your weight training program so that you allow time for your muscles to recovery in between workouts. Try to avoid weight training on consecutive days, even if you are targeting different muscle groups.
Don't forget that your body only builds muscle tissue when you are not weight training. Simply put, you build muscle while you are sleeping, not while you are at the gym! If you weight train and don't get an enough sleep, or train too often it can become nearly impossible to build muscle. (From this site)