During the initial stages of exercise, muscle glycogen is the primary source of energy to replenish the immediate energy systems. But as stored levels begin to deplete, a greater emphasis is placed upon blood glucose. This can have major implications to resistance training. As many individuals now consume lower carbohydrate diets, stored glycogen levels can be much below the 15g/kg upper range. This can create a significant deficit during training due to cumulative effects of physical activity. Short-term bouts of high intensity training with very short or active rest periods will elicit a significant level of muscle glycogenolysis. There appears to be a linear relationship between muscle glycogenolysis, external work performed, and exercising intensity. As a result, training intensity can severely drop off once short-term energy stores are depleted.
By consuming a readily bioavailable source of carbohydrates immediately before and after training, can create a metabolic switch earlier in training. Because of the available blood glucose, the active muscle cells will not use as stored glycogen during training. In turn, the there will be a prolonging effect upon performance as well as an early jumpstart upon recovery.
