Nutrition intake, protein distribution and gains in lean mass in developing elite rugby players

Kristen MacKenzie, Neil King, Nuala Byrne, Gary Slater

Research output: Contribution to conferenceAbstractResearch


Numerous dietary factors can impact adaptations to resistance exercise. The role of protein intake, including
digestion rate, amino acid composition, protein dose and daily distribution have been a research focus in recent
years. However, other dietary components, including the intake of other macronutrients and energy, may also
influence adaptation. Consequently, when assessing the influence of protein intake and distribution in research
and practice these other dietary factors must be considered. Therefore, we explored the impact of nutritional
intake in conjunction with a protein distribution manipulation on gains in lean mass over a rugby pre-season.
Twenty-four male developing elite rugby athletes (age 20.1 ± 1.4 yr, mass 101.6 ± 12.0 kg) were recruited while
undertaking their usual pre-season training. They were instructed to consume high biological value (HBV)
protein at their main meals and immediately after resistance exercise while limiting additional protein intake
between meals. To manipulate the HBV protein intake frequency, they consumed 3 supplied HBV liquid protein
supplements (22 g each) per day either between meals (FREQUENT) or with their main meals (BOLUS) for 6
weeks in a 2 x 2 crossover design. Total energy and macronutrient intake was measured by multiple 24 hour
recalls and body composition assessed by Dual Energy X-Ray Absorptiometry (DXA) with values compared
between conditions. The association between changes in lean mass and dietary intake were assessed by
correlational analysis.
Protein distribution was manipulated from ~4 to ~6 eating occasions containing more than 20 g of protein per
day, for the BOLUS and FREQUENT conditions. There was no difference in gains in lean mass for the BOLUS
(1.4 ± 1.5 kg) or FREQUENT (1.5 ± 1.4 kg) conditions (P = 0.91) respectively. However, the correlation
between average total energy intake and total change in lean mass was significant (r = 0.43; P = 0.04).
Therefore, other dietary factors such as dietary energy intake did augment adaptation and thus should be
considered when manipulating protein intake to promote gains in lean mass.
Original languageEnglish
Publication statusPublished - 10 Apr 2014
Externally publishedYes
EventThe 6th Exercise & Sports Science Australia Conference and Sports Dietitians Australia : Research to Practice - Adelaide Exhibition Centre, Adelaide, Australia
Duration: 10 Apr 201412 Apr 2014
Conference number: 6


ConferenceThe 6th Exercise & Sports Science Australia Conference and Sports Dietitians Australia
Abbreviated titleESSA
OtherResearch to Practice, organised by Exercise & Sports Science Australia and Sports Dietitians Australia, will bring together over 1,000 delegates, both international and domestic keynote speakers, more than 30 high-level speakers, over 40 national exhibitors and representatives from a number of health associations. The biennial event will focus on a strong scientific program combined with expert panels, interactive sessions, real life case studies, workshops, and presentations on the latest trends and discoveries in the field of exercise, sports science and nutrition. The program incorporates streams on: Sports Science, Exercise Science, Exercise is Medicine, and Nutrition.


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