Protein dose and quantity amongst elite rugby players

Introduction: Optimising protein intake to promote gains in skeletal muscle mass (SMM) isconsidered important by many athletes (Phillips et al, 2007). Research has suggested thatmuscle protein synthesis may be optimised by a single 20g protein dose (approximately~0.3g·kg-1body mass) with no further stimulation at higher doses (Moore et al, 2007). Oneacute study reported enhanced muscle protein synthesis when protein was consumed afterresistance training as several small 20g doses, rather than larger, less frequent doses (Aretaet al, 2012). This study aimed to examine self-reported protein distribution and dose in elitedevelopment rugby union athletes. A secondary aim was to assess the relationship betweenprotein distribution and changes in fat-free mass (FFM) over a rugby pre-season.Methods: 25 athletes (20.5±2.3yrs; 100.2±13.3kg) completed a 7d food diary. Food portionguides and Foodworks v.6.0.2562 (2009) were used to quantify food intake. Proteindistribution scores were calculated as the number of times an eating occasion (>15 minutesapart) achieved a target amount of protein (20g or individually calculated target based on0.3g·kg-1i.e. 30.0±4.0g) averaged per day. FFM was measured by dual energy x-rayabsorptiometry.Results: The mean number of eating occasions was 5.6±1.0. The protein distribution scoresfor 20g and calculated protein target were 3.8±1.0 (68±18% of eating occasions) and 2.8±1.1(50±20% of eating occasions) respectively. 2.0±0.9 (36±16%) of all eating occasionsexceeded the calculated protein target by more than 50%. The effect of 20g proteindistribution score on changes in FFM was not significant (p=0.15); regression analysis wasimpacted by statistical power and multicollinearity.Discussion: This study provides evidence that rugby players select a meal plan that includeslarger, less frequent doses of protein. However, it is unclear whether protein distributionimpacts on chronic changes in FFM. Chronic studies monitoring associations between dietaryintake and protein distribution on changes in FFM or SMM pose several methodological andanalytical challenges. Acute studies may assist by clarifying the optimal protein distributionand protein doses for changes in indicators of SMM synthesis. Further research is warrantedto assess the impact of protein dose and distribution, with consideration of other dietary intakevariables, on chronic changes in body composition amongst rugby union athletes.