From what I've gathered from "the bear" science, once your body has fully-adapted to a carbless environment you will use very little glycogen during exercise. Glycogen levels on zc are apparently naturally at a lower level and seem to remain stable even while exercising. But, hes been wrong on a number of occasions I wouldn't read much into this.
A number of other zc'ers (such as myself) have noticed that it takes a bit longer to get back to full strength after heavy lifting. Perhaps this is because of the limited amount of ways the body can store glycogen. I suppose it makes sense that eating lots of protein will help you refill your glycogen stores but this doesn't seem healthy at all consuming this much protein unless you are an elite bodybuilder and even then 300g is probably too much. I would actually heavily advise against that much protein.
What I want to look into more is whether eating glycogen rich animal foods such as beef liver would fill my glycogen stores directly instead of having my body first break down the protein to glucose and then use this glucose to form glycogen. The USDA nutrient database says that there is 4 grams of carbs per 100g in beef liver. It doesn't however say that all these carbs are glycogen.
I'm going to postulate an example, a highly haphazard one, but an example nonetheless to see what might happen during exercise. From various internet searches the body is composed of 42% of skeletal muscle mass and in the muscle there is 1-2% glycogen, though I think its closer to 1%. So an 80kg male will have around 34kg of muscle and about 400 grams of glycogen. Further searching says that the average person has 200-500g of glycogen so the 400g is in the ballpark. According to wiki glycogen stores are fully depleted after about 2 hours of intense running or cycling so glycogen is used up at around 200g per hour.
So now we can use this highly bastardized statistic to see how much glycogen we need to refill for ourselves. So for instance, If I play basketball intensely for half an hour perhaps I will use 50g of glycogen. But maybe now that Im zc and can more efficiently utilize fat I will use substantially less, maybe 20g and so the task of replenishing might not be that hard. Im going to stop my example now as Ive made numerous assumptions but I think you get the point.