The need for protein appears to be greater for the strength and power athlete than for the endurance-trained athlete or the sedentary population. The higher protein pool is thought to enhance the recovery and remodeling processes of muscle fibers that have been damaged or disrupted during resistance exercise. Recent studies have shown decreases in muscle damage, attenuation of force decrements, and an enhanced recovery from resistance exercise in individuals using protein supplements.
Acute Protein Intake Before and/or After Resistance Exercise
The timing of protein ingestion appears to be critical in maximizing the anabolic response from resistance exercise. Previous studies have suggested that between 20% and 90% of the amino acids are removed from the circulation as they initially pass through the liver and that perhaps more are removed during exercise. However, later examination showed comparable changes in net muscle protein balance (synthesis- degradation) from both oral and infused ingestion of essential amino acids after resistance exercise. This would indicate that the oral consumption of protein, typically employed by most individuals ingesting protein supplements, is efficacious in enhancing the anabolic response to resistance exercise.
Rasmussen in 2000 revealed that essential amino acids and carbohydrate supplement combination was given prior to exercise, the increase in muscle protein synthesis was significant greater than when given immediately after exercise. Tipton (1999) demonstrated that when amino acids were provided immediately before exercise, the amino acid concentration within skeletal muscle increased 46% by the end of exercise and was elevated further (86% above rest) an hour after exercise. Thus ingestion of amino acids combined with carbohydrates before the onset of exercise appears to be a potent stimulator of amino acid delivery via an increased blood flow to exercising muscle and subsequent muscle uptake, resulting in greater protein synthesis than consuming this supplement after exercise.
Differences in Whey and Casein Protein Ingestion on Protein Accretion
Casein and Whey are two proteins from bovine milk that have different digestive properties. Casein, which is the pre-dominant milk protein, exists in the form of a micelle which is a large colloidal particle. The casein micelle forms a gel or clot in the stomach that makes it slow to digest. As a result, casein provides a sustained but slow release of amino acids into the blood stream, sometimes lasting for several hours. Whey protein accounts for 20% of bovine milk (casein accounting for 80%) that contains high levels of the essential and branched chain amino acids. Whey protein is the translucent liquid part of milk that remains after the process of cheese manufacturing; as a result it is absorbed into the body much quicker than casein.
Boirie (1997) demonstrated that after whey protein ingestion, the plasma appearance of amino acids is fast and transient. In contrast, casein is absorbed more slowly, producing a much less dramatic rise in plasma amino acid concentrations. Whey protein ingestion stimulated protein synthesis by 68%, while casein ingestion stimulated protein synthesis by 31%.
Timing and Training Studies
Tipton (2001) and Rasmussen (2000) demonstrated that essential amino acids ingested prior to resistance exercise stimulates greater muscle protein synthesis than essential amino acids consumed immediately after or 1-3 hours after exercise. These results suggest that protein supplement timing may be critical in stimulating muscle adaptations that occur during prolonged training. Cribb and Hayes (2006) examined the effect of a protein and carbohydrate supplement in young (21-24 years old) recreationally trained male bodybuilders consumed immediately before and after resistance training. The group consuming the supplement immediately before and after the workouts experienced significantly greater gains in lean body mass and increases in the size of type II muscle fibers. This was in comparison to the group that ingested protein in the morning and in the evening.
Summary – Practical Applications
Evidence strongly indicates that the proper timing of protein ingestion provides a distinct advantage in stimulating muscle protein synthesis rates and subsequent muscle adaptations. It appears that a whole protein and carbohydrate supplement should be consumed immediately after or within an hour of an exercise session.
**Remember to:
1) Always plan ahead for what you are going to eat
2) Obtain adequate amounts of protein
3) Work on your flexibility
4) Supplement your diet with a fish oil and multivitamin
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