Assessment of energy availability and associated risk factors in professional female soccer players

Abstract

This study aimed to assess energy availability (EA), alongside possible risk factors of reduced or low EA of professional female soccer players during a competitive season. Thirteen players (age: 23.7 ± 3.4 y, stature: 1.69 ± 0.08 m, body mass: 63.7 ± 7.0 kg) engaged in a 5-day (two rest days, one light training, heavy training and match day) monitoring period. Energy intake (EI) and expenditure during exercise (EEE) were measured. EA was calculated and categorised as optimal, reduced or low (>45, 30-45, <30 kcal•kg FFM −1 •day −1 , respectively). Relationships between EA and bone mineral density, resting metabolic rate (RMR), plasma micronutrient status, biochemical markers and survey data were assessed. EA was optimal for 15%, reduced for 62% and low for 23% of players. Higher EA was observed on rest days compared to others (P<0.05). EA was higher for the light compared to the heavy training day (P<0.001). EEE differed significantly between days (P<0.05). EI (2124 ± 444 kcal), carbohydrate (3.31 ± 0.64 g•kg•day −1 ) and protein (1.83 ± 0.41 g•kg•day −1 ) intake remained similar (P>0.05). Survey data revealed 23% scored ≥8 on the Low Energy Availability in Females Questionnaire and met criteria for low RMR (ratio <0.90). Relationships between EA and risk factors were inconclusive. Most players displayed reduced EA and did not alter EI or carbohydrate intake according to training or match demands. Although cases of low EA were identified, further work is needed to investigate possible long-term effects and risk factors of low and reduced EA separately to inform player recommendations.

Injury Incidence Across the Menstrual Cycle in International Footballers

“…When dietary energy availability is limited, key physiological processes such as the menstrual cycle are sacrificed to conserve energy, resulting in oligomenorrhea or amenorrhea, and greater injury incidence has been observed in athletes and military recruits with extended cycle durations (Rauh et al, 2010 ; Knapik et al, 2013 ). Moss et al ( 2020 ) showed that 23% of elite female footballers had low (≤ 30 kcal·kg·FFM −1 ·day −1 ) energy availability and menstrual dysfunction has been observed in 9.3–19.3% of elite footballers (Sundgot-Borgen and Torstveit, 2007 ; Prather et al, 2016 ). To date, the impact of extended menstrual cycle duration has not been explored in relation to injury risk.…”

Physiological Characteristics of Female Soccer Players and Health and Performance Considerations: A Narrative Review

“…Soccer players score lower than non-athlete controls on scores of disordered eating, and the proportion of self-reported eating disorders (5.9%) is lower than other sports and controls [128]. However, 8.0-19.3% of elite soccer players report menstrual dysfunction [129][130][131], a symptom of low EA. [129].…”

“…This suggests that opportunities for energy intake should be maximised on match and heavy training days to prevent a recurring pattern of sub-optimal EA. This was a consequence of dietary energy intake not matching energetic demands [129]. Collectively, it appears that the majority of incidence of low EA occurred when energy intake was not adjusted to the energetic demands of training or match-play.…”

“…However, 8.0-19.3% of elite soccer players report menstrual dysfunction [129][130][131], a symptom of low EA. [129]. This suggests that opportunities for energy intake should be maximised on match and heavy training days to prevent a recurring pattern of sub-optimal EA.…”

Association of Low Energy Availability and Suppressed Metabolic Status in Korean Male Collegiate Soccer Players: A Pilot Study

“…A previous study on Japanese male runners (19–21 years) has identified that a high risk of having low EA in this populations exists, leading to metabolic suppression and increased bone resorption ( Taguchi et al, 2020 ). Studies on professional female and male soccer players during training period provided the evidences that energy deficiency and low EA can be found in the different sports ( Moss et al, 2020 ; Reed et al, 2014 ; Russell & Pennock, 2011 ). These studies can support the IOC consensus statement on RED-S in male athletes with different ethnicities and sports background.…”