Energy Availability and Macronutrient Intake of Professional Rugby Players During Pre-season Training

Abstract

Background: In 2014, the International Olympic Committee officially recognised low energy availability to have negative effects on the health and performance of male athletes. Despite this, there is still only a small body of research investigating the prevalence and consequences of low energy availability in male athletes. Rugby union players need to be lean and muscular in order to maximise the power to weight ratio and provide a competitive advantage. As a result, these athletes often have body weights much higher than those involved in other sports. When combined with large body weight, the energy demands of the pre-season training period may mean that rugby union players are at risk of low energy availability. Objective: The primary aim of this study was to determine the prevalence of low energy availability in elite male rugby union players during the pre-season. Secondary to this, we aimed to assess the macronutrient composition of participants’ diets in comparison to sports nutrition recommendations. Design: During this three-day observational study, three-day diet records were collected for 23 participants using a variety of collection methods- video, photographs, checklists and recalls. Energy expenditure data was also collected via heart rate monitoring, GPS tracking and Activity Logs. Data was analysed as groups established by pre-season training goal: weight gain (n=8)/weight maintenance (n=8)/weight loss (n=7). Results: The weight loss group had significantly lower mean (±SD) energy availability (4.1±9.0kcal.kgFFM-1.day-1) than the weight maintenance (20.3±7.6kcal.kgFFM-1.day-1, p=0.003) and weight gain (28.6±8.0kcal.kgFFM-1.day-1, p<0.001) groups. Carbohydrate intake was significantly higher for the weight gain group (mean± SD: 4.8±0.9g.kg-1.day-1) compared to other groups (weight maintenance: 3.5±0.7g.kg-1.day-1, p=0.018; weight loss: 2.4±0.8g.kg-1.day-1, p<0.001). Protein intake was significantly higher in the weight gain group (2.3±0.4g.kg-1.day-1, p=0.019) than the weight loss group (1.7±0.5g.kg-1.day-1). There were no significant differences between groups in percent of total calories from fat. Conclusion: The current research shows that during the pre-season, around 70% of elite rugby union players were in a state of low energy availability. Macronutrient intakes were similar to those found in previous studies of rugby league and union athletes: the low energy availability encountered in this study may be a result of dietary carbohydrate being displaced due to large amounts of protein and fat being consumed. Future research in this group should assess energy availability during different times of the season and with a larger sample size.