Glycogen and water in muscle have great influence on its size. In fact, studies have shown that muscle glycogen can increase musclevolume by about 16%. Moreover, some studies have found that when you stop training for a week, your muscle glycogen level can drop by 20%. This means that when you don't go to the gym for a while, your muscles will look smaller, which may be something you have experienced. But the good news is that after you start retraining, your muscle sugar raw water level and water reserve will recover soon.