Regulation of muscle glycogen repletion, muscle protein synthesis and repair following exercise

Abstract

Recovery from prolonged strenuous exercise requires that depleted fuel stores be replenished, that damaged tissue be repaired and that training adaptations be initiated. Critical to these processes are the type, amount and timing of nutrient intake. Muscle glycogen is an essential fuel for intense exercise, whether the exercise is of an aerobic or anaerobic nature. Glycogen synthesis is a relatively slow process, and therefore the restoration of muscle glycogen requires special considerations when there is limited time between training sessions or competition. To maximize the rate of muscle glycogen synthesis it is important to consume a carbohydrate supplement immediately post exercise, to continue to supplement at frequent intervals and to consume approximately 1.2 g carbohydrate·kg(-1) body wt·h(-1). Maximizing glycogen synthesis with less frequent supplementation and less carbohydrate can be achieved with the addition of protein to the carbohydrate supplement. This will also promote protein synthesis and reduce protein degradation, thus having the added benefit of stimulating muscle tissue repair and adaptation. Moreover, recent research suggests that consuming a carbohydrate/protein supplement post exercise will have a more positive influence on subsequent exercise performance than a carbohydrate supplement. Key PointsFor rapid recovery from prolonged exercise, it is important to replenish muscle glycogen stores and initiate muscle tissue repair and adaptation.To maximize muscle glycogen replenishment, it is important to consume a carbohydrate supplement as soon after exercise as possible.Consume the carbohydrate frequently, such as every 30 minutes, and provide about 1.2 to 1.5 g of carbohydrate·kg(-1) body wt·h(-1).Efficiency of muscle glycogen storage can be increased significantly with the addition of protein to a carbohydrate supplement (~4 to 1 carbohydrate to protein ratio).The addition of protein to a carbohydrate supplement also has the added advantage of limiting post exercise muscle damage and promoting muscle protein accretion.

Keywords: Carbohydrate; amino acids; glucose; insulin; nutrients.