Nutrition for Female Athletes: what we know, what we don't know, and why

Energetics of a World-Tour Female Road Cyclist During a Multistage Race (Tour de France Femmes)

Despite the increased popularity of female elite road cycling, research to inform the fueling requirements of these endurance athletes is lacking. In this case study, we report for the first time the energetics of a female world-tour cyclist competing in the 2023 Tour de France Femmes, an 8-day race of the Union Cycliste Internationale. The 29-year-old athlete presented with oligomenorrhea and low T3 before the race. Total daily energy expenditure assessed with the doubly labeled water technique was 7,572 kcal/day (∼4.3 physical activity levels), among the highest reported in the literature to date for a female. Crank-based mean maximal power was consistent with female world-tour cyclists (5 min, mean 342 W, 4.8 W/kg; 20 min 289 W, 4.1 W/kg). The average daily energy intake measured with the remote food photography method (Stage Days 1-7) was 5,246 kcal and carbohydrate intake was 13.7 g/kg (range 9.7-15.9 g/kg), and 84 g/hr during stages, and an average fat intake of 15% of daily energy intake. An estimated 2,326 kcal/day energy deficit was evidenced in a 2.2 kg decrease in body mass. Notwithstanding the high carbohydrate intake, the athlete was unable to match the energy requirements of the competition. Despite signs of energy deficiency preexisting (oligomenorrhea and low T3), and other further developing during the race (weight loss), performance was in line with that of other world-tour cyclists and a best personal performance was recorded for the last stage. This case study emphasizes the need for further research to inform energy requirements for female athletes' optimal performance and health.

Is the Elite Female Athlete's Pelvic Floor Stronger?

Background: Exercise can stress the pelvic floor muscles (PFMs). This study sought to assess the strength of the PFMs according to the level of physical exercise. Methods: An analytical observational study was carried out using digital palpation and dynamometry measurements to assess PF strength. Healthy nulliparous women were stratified according to physical exercise (physically active and sedentary) and level of physical exercise (elite, amateur, and sedentary). Results: Fifty-four women were analyzed, with a mean age of 25.64 (5.33) years and a BMI of 21.41 (2.96) kg/m2. Differences in the passive force and strength were observed between both groups of women (p < 0.05), and the strength was around two times higher in physically active women (p < 0.05). The strength was similar between elite female athletes and sedentary women (p > 0.05), but statistical differences were found with amateurs (p < 0.05). The PFM strength (p = 0.019) of elite female athletes (0.34 N) was almost half that of amateurs (0.63 N) and twice as strong as that of sedentary women (0.20 N). However, these differences were not significant using digital palpation (p = 0.398). Conclusions: Women who exercise generally have greater PFM strength than women who do not exercise. Physical exercise could strengthen the PFM; however, the high intensity demanded by high-level sports does not seem to proportionally increase the strength of the PFMs.

Bridging the gap: Evidence-based practice guidelines for sports nutritionists

Evidence-based practice is a systematic approach to decision-making developed in the 1990s to help healthcare professionals identify and use the best available evidence to guide clinical practice and patient outcomes amid a plethora of information in often challenging, time-constrained circumstances. Today’s sports nutrition practitioners face similar challenges, as they must assess and judge the quality of evidence and its appropriateness to their athlete, in the often chaotic, time-pressed environment of professional sport. To this end, we present an adapted version of the evidence-based framework to support practitioners in navigating their way through the deluge of available information and guide their recommendations to athletes whilst also reflecting on their practice experience and skills as evidence-based practitioners, thus, helping to bridge the gap between science and practice in sport and exercise nutrition.

Energy expenditure, dietary intake and energy availability in female professional football players

Objectives

To quantify energy expenditure and intake in professional female footballers playing on a national and/or international level. Second, to determine the prevalence of low energy availability among these players, defined as <30 kcal/kg fat-free mass (FFM)/day.

Methods

Fifty-one players completed a 14-day prospective observational study during the 2021/2022 football season. Energy expenditure was determined using the doubly labelled water method. Energy intake was assessed using dietary recalls, while global positioning system determined the external physiological load. Descriptive statistics, stratification and the correlation between explainable variables and outcomes were conducted to quantify the energetic demands.

Results

The mean energy expenditure for all players (22±4 years) was 2918±322 kcal. Mean energy intake was 2274±450 kcal, resulting in a discrepancy of ~22%. Carbohydrate intake was below the recommended guidelines on match day at 4.5±1.9 g/kg. The mean energy availability was 36.7±17.7 kcal/kg FFM/day on matchday and 37.9±11.7 kcal/kg FFM/day on training days, resulting in a prevalence of 36% and 23% for low energy availability during the observational period, respectively.

Conclusion

These elite female football players displayed moderate energy expenditure levels and failed to meet the recommended levels of carbohydrate intake. In conjunction with inadequate nutritional periodisation, this will likely hamper performance through inadequate muscle glycogen resynthesis. In addition, we found a considerable prevalence of low energy availability on match and training days.

Current evidence shows no influence of women's menstrual cycle phase on acute strength performance or adaptations to resistance exercise training

Introduction

The bias towards excluding women from exercise science research is often due to the assumption that cyclical fluctuations in reproductive hormones influence resistance exercise performance and exercise-induced adaptations.

Methods

Hence, the purpose of this umbrella review was to examine and critically evaluate the evidence from meta-analyses and systematic reviews on the influence of menstrual cycle phase on acute performance and chronic adaptations to resistance exercise training (RET).

Results

We observed highly variable findings among the published reviews on the ostensible effects of female sex hormones on relevant RET-induced outcomes, including strength, exercise performance, and hypertrophy.

Discussion

We highlight the importance of comprehensive menstrual cycle verification methods, as we noted a pattern of poor and inconsistent methodological practices in the literature. In our opinion, it is premature to conclude that short-term fluctuations in reproductive hormones appreciably influence acute exercise performance or longer-term strength or hypertrophic adaptations to RET.