This study looked at the rate of muscle glycogen synthesis during 2 and 4 hours of recovery after depletion by exercise using two energy equivalent carbohydrate drinks. (bodybuildingforyou.com)
Muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion. (precisionnutrition.com)
Above this amount, the rate of muscle glycogen synthesis is unchanged. (perfecthealthdiet.com)