Studies indicate that high quality protein can stimulate muscle protein synthesis after both resistance and endurance exercise. In a recent study, highly trained cyclists exercised for 90 minutes on 2 occasions. Immediately after exercise and then again 30 minutes later, the subjects consumed 25g of carbs (50g total). During 1 of the trials, subjects added 10g of whey protein isolate to the carbs, providing a total of 20g of protein.
As expected, only the carb-protein trial resulted in increased levels of amino acids in the blood. The rate of mitochondrial protein synthesis was not different between trials. However, contractile muscle protein synthesis was 35% greater during the carb-protein trial compared to the carb-only trial.
The results point to the importance for endurance athletes to add protein to recovery drinks for the purpose of specifically increasing proteins responsible for muscle contraction.