PROTEIN "CHARGING" STRATEGIES IN ATHLETES
Adaptations to training are optimized when the 3 "R's" of the post-exercise period are satisfied, that is Rehydrate, Replenish (glycogen stores) and Repair (exercise-induced muscle damage). When it comes to Repair, protein consumption stimulates muscle protein synthesis and in fact has a synergistic effect on resistance exercise-induced muscle protein synthesis (1). Guidelines for protein RDA currently are at 0.8 gr protein·kg-1 body mass·day-1, however guidelines on protein intakes for athletes are in the range of 1.2-1.7 protein·kg-1 body mass·day-1 (2). Therefore for a 75kg athlete the above recommendation would translate into 90-130 gr protein per day.
has been demonstrated that postprandial contractile muscle protein synthesis following high-intensity resistance exercise plateaus with 20 gr of ingested whey protein (3); a similar dose-response has been reported for egg-protein (4). What is important to note is that when higher amounts of protein were ingested these were ultimately either excreted or oxidized (3). Therefore, instead of ?packing? the vast majority of the daily protein intake into 1-2 major meals (e.g., lunch or dinner), a perhaps better strategy would be to evenly ?spread? the protein consumption on a meal-by-meal basis. In the above example the athlete should thus ?spread? protein consumption approximately evenly on 4-6 meals which would result in 20-25 gr of protein intake per meal. Typical examples of foods containing ~25 g of protein are ~750 mL of skimmed milk, 4-5 eggs or 100 g of lean beef. Therefore meeting the target of 20-25 gr of protein is relatively easy for breakfast, lunch, dinner. A fourth option for ingesting protein is immediately after training/exercise because it promotes greater stimulation of muscle protein synthesis (1) and also reduces the symptoms of soreness related to the preceding exercise-induced muscle damage (5). Another, less explored, ?window? for protein feeding is prior to bedtime. It has been demonstrated that ingesting slow-releasing casein immediately prior to bedtime stimulated a greater overnight response of muscle protein synthesis (6), whilst providing a combination of casein and casein hydrolysate in a 1:1 ratio before bed time augmented strength gains over a 12-week period of resistance training (7).
- Churchward-Venne TA, Burd NA, Phillips SM. Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism. Nutr Metabol (Lond), 2012; 9: 40.
- Rodriguez NR, Di Marco NM, Langley S. American College of Sports Medicine position stand. Nutrition and athletic performance. Med Sci Sports Exerc, 2009; 41: 709-731.
- Witard OC, et al. Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. Am J Clin Nutr, 2014: 99: 86-95.
- Moore DR, et al. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr, 2009: 89: 161-168.
- Jackman SR, et al. Branched-chain amino acid ingestion can ameliorate soreness from eccentric exercise. Med Sci Sports Exerc, 2010: 42: 962-970.
- Res PT, et al. (2012). Protein ingestion before sleep improves post-exercise overnight recovery. Med Sci Sports Exerc, 2012; 44: 1560-1569.
- Snijders T, et al. Protein ingestion before sleep increases muscle mass and strength gains during prolonged resistance-type exercise training in healthy young men. J Nutr, 2015; 145: 1178-1184.
Kostas Patras MD, PhD
Research Fellow Orthopaedic Sports Medicine Center of Ioannina