2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs)

Collegiate women's wrestling body fat percentage and minimum wrestling weight values: time for revisiting minimal body fat percent?

BACKGROUND

The estimation of body fat percentage (BF%) in wrestling is used to determine the minimum wrestling weight (MWW) and lowest allowable weight class (MWC) in which wrestlers are eligible to compete. A 12% minimum threshold is currently used for women wrestlers, yet a potential increase for safety has been discussed. Because of the novelty of collegiate women's wrestling, there is a paucity of literature available on the body composition norms of this population. The purpose of this study was to provide a descriptive summary of BF% and MWW values of female wrestlers and how MWW values would change with the use of different BF% thresholds.

METHODS

Data from the 2022-2023 collegiate season were retrospectively analyzed resulting in a sample of 1,683 collegiate women wrestlers from the National Association of Intercollegiate Athletics (NAIA, n = 868) and the National Collegiate Athletics Association (NCAA, n = 815). All wrestlers completed skinfold assessments for weight certification at the start of the competition season. The skinfold values were used to estimate BF% using the Slaughter skinfold prediction equation. Frequency statistics and descriptive analysis were performed to compute normative MWW and BF% profiles. BF% thresholds of 12% (12MWW) and the BF% value defined as the lowest 5th percentile, which would be considered unusually lean, were used to determine the resulting MWW and MWC for each method. The lowest recorded weight and weight class division throughout the season was also recorded for each wrestler.

RESULTS

There was a positively skewed (0.94) and platykurtic (1.86) distribution of MWW values. The median ± interquartile range BF% for all wrestlers was 27.4 ± 10.22%, with 17% BF representing the 5th percentile. Only 354 out of 1,579 (22.4%) wrestlers competed in their lowest allowable weight class, based on the 12MWW. Of these 354 wrestlers, the mean BF% was 21.3 ± 5.2% at weight certification with only n = 17 being at or below 12% body fat and an average weight loss of 11.1 ± 8.8 lbs. from the time of weight certification. Throughout the season, wrestlers competed at weights that were, on average (mean ± SD), 19.4 ± 16.9 lbs. higher than their 12MWW (95% CI: 18.6, 20.2 lbs. p < 0.001; effect size [ES] = 1.1), 13.4 ± 19.0 lbs. higher than the 17MWW (p < 0.001; ES = 0.70), and 8.7 ± 8.3 lbs. lower than their weight at the certification (95% CI: 8.3, 9.1 lbs. p < 0.001; ES = 1.1).

CONCLUSIONS

Nearly all BF% values were well above the 12% threshold used to determine MWW. Increasing the minimum BF% threshold from 12% to 17% would affect a small percentage of wrestlers, likely reduce the need for excessive weight cutting, and minimize the deleterious health effects of an athlete at such a low BF%.

Standardising health history and injury surveillance of participants in endurance events: a modified Delphi consensus statement from the AMSSM runner health consortium

Endurance events are popular worldwide and have many health benefits. However, runners and Para athletes may sustain musculoskeletal injuries or experience other health consequences from endurance events. The American Medical Society for Sports Medicine (AMSSM) Runner Health Consortium aimed to generate consensus-based survey items for use in prospective research to identify risk factors for injuries in runners and Para athletes training and competing in endurance events. The study design employed a modified Delphi approach, with a panel comprising 28 experts, including healthcare professionals, coaches, and athletes. Potential survey items were generated by panel members who subsequently engaged in three rounds of voting using Research Electronic Data Capture. Items were graded by clarity, relevance, and importance. Items achieving 80% consensus on all three aspects were retained. The response rate was 100% in R round 1 and 96% in Rrounds 2 and 3. Of 124 initial survey items, consensus was reached on 53, 34 and 22 items during Rrounds 1, 2, and 3, respectively. Two accepted items were removed due to redundancy. Combined with 10 non-voting items, 117 items covered key domains, including training and injury history, dietary behaviours and associated factors (such as menstrual function), footwear, mental health, and specific considerations for Para athletes. The consensus-based survey items should be considered by researchers to better understand the health of runners and Para athletes who train and compete in endurance sports to identify risk factors for injury.

Commonly Used Indicators of Low Energy Availability Risk Fail to Identify Female Amateur Soccer Players With Measured Low Energy Availability During Preseason

This study aimed to determine energy availability (EA) and within-day energy balance (WDEB) in female soccer players during preseason and also explored eating disorder risk and athlete food choice. We hypothesized commonly used indicators of low energy availability (LEA) risk would correlate with measured EA and WDEB variables, and that food choice determinants would differ according to EA. Eleven National Premier League female soccer players participated in this observational cross-sectional study over 3 weeks. Assessment of resting metabolic rate and physique traits, including bone mineral density, was conducted during Weeks 1 or 3. During Week 2, dietary intake, energy expenditure, and continuous monitor-derived glucose were measured for 5 days. EA was calculated daily and WDEB calculated hourly with deficits/surpluses carried continuously. Questionnaires were administered throughout the 3 weeks, including the Athlete Food Choice Questionnaire, the Eating Disorders Screen for Athletes, and the Low Energy Availability in Females Questionnaire. Resting metabolic rate ratio, bone mineral density, Low Energy Availability in Females Questionnaire, and Eating Disorders Screen for Athletes scores were used as indicators of LEA risk. EA averaged 30.7 ± 7.5 kcals·kg fat-free mass-1·day-1. Approximately one-third (36%) of athletes were at risk of an eating disorder, while approximately half (45%) were identified at risk of the female athlete triad via Low Energy Availability in Females Questionnaire, compared with approximately one-third (36%) of athletes identified with EA < 30 kcal·kg fat-free mass-1·day-1. No athlete achieved EA >45 kcal·kg fat-free mass-1·day-1, and no indicator of LEA risk was associated with calculated EA or WDEB. However, overnight glycemic variability was positively correlated with measured EA (r = .722, p = .012).

Cross-sectional size, shape, and estimated strength of the tibia, fibula and second metatarsal in female collegiate-level cross-country runners and soccer players

Bone stress injuries (BSIs) frequently occur in the leg and foot long bones of female distance runners. A potential means of preventing BSIs is to participate in multidirectional sports when younger to build a more robust skeleton. The current cross-sectional study compared differences in tibia, fibula, and second metatarsal diaphysis size, shape, and strength between female collegiate-level athletes specialized in cross-country running (RUN, n = 16) and soccer (SOC, n = 16). Assessments were performed using high-resolution peripheral quantitative computed tomography and outcomes corrected for measures at the radius diaphysis to control for selection bias and systemic differences between groups. The tibia in SOC had a 7.5 % larger total area than RUN, with a 29.4 % greater minimum second moment of area (IMIN) and 8.2 % greater estimated failure load (all p ≤ 0.02). Tibial values in SOC exceeded reference data indicating positive adaptation. In contrast, values in RUN were similar to reference data suggesting running induced limited tibial adaptation. RUN did have a larger ratio between their maximum second moment of area (IMAX) and IMIN than both SOC and reference values. This suggests the unidirectional loading associated with running altered tibial shape with material distributed more in the anteroposterior (IMAX) direction as opposed to the mediolateral (IMIN) direction. Comparatively, SOC had a similar IMAX/IMIN ratio to reference data suggesting the larger tibia in SOC resulted from multiplane adaptation. In addition to enhanced size and strength of their tibia, SOC had enhanced structure and strength of their fibula and second metatarsal. At both sites, polar moment of inertia was approximately 25 % larger in SOC compared to RUN (all p = 0.03). These data support calls for young female athletes to delay specialization in running and participate in multidirectional sports, like soccer, to build a more robust skeleton that is potentially more protected against BSIs.

Snooze it or Lose it: Understanding Sleep Disturbance and Injuries in Soccer and Basketball Student-Athletes

OBJECTIVES

To assess the sleep characteristics of collegiate soccer and basketball student-athletes and explore the associations between sleep and injury risk.

DESIGN

Cohort study.

SETTING

NCAA D1 and NAIA Tier 1.

PARTICIPANTS

One hundred eighty-one collegiate soccer and basketball student-athletes (42% female; mean age: 20.0 ± 1.7 years).

INDEPENDENT VARIABLES

Questionnaires were administered during the 2020/2021 and 2021/2022 preseason, collecting demographic, injury history, medical history, and sleep information, including sleep difficulty category scores of 0 to 4 (none), 5 to 7 (mild), and ≥8 (moderate/severe) and other sleep disturbance measures derived from the Athlete Sleep Screening Questionnaire (ASSQ), including insufficient sleep duration (<7 hours of sleep) and poor subjective sleep quality.

MAIN OUTCOME MEASURES

All-complaint knee and ankle injuries.

RESULTS

According to the ASSQ, 25.4% (95% confidence interval [CI], 17.9-34.3) of the student-athletes had mild sleep difficulty and 12.7% (95% CI, 7.3-20.1) had moderate/severe sleep difficulty. 36.1% (95% CI, 29.1-43.6) had insufficient sleep duration. 17.1% (95% CI, 11.7-23.7) were not satisfied with the quality of their sleep (poor sleep quality), and 13.8% (95% CI, 9.1-19.7) had an "eveningness" chronotype. Based on multivariable logistic regression models, student-athletes with poor sleep quality had significantly higher odds for injury (OR: 2.2, 95% CI, 1.04-4.79, P = 0.039).

CONCLUSIONS

Clinically relevant dysfunctional sleep patterns are prevalent among collegiate soccer and basketball student-athletes. Poor sleep quality was significantly associated with injury risk among student-athletes. Findings suggest a substantial sleep problem in collegiate soccer and basketball student-athletes and warrant that student-athletes are regularly screened and timely interventions applied.

Low Energy Availability and Relative Energy Deficiency in Sport: A Systematic Review and Meta-analysis

INTRODUCTION

Low energy availability (LEA) occurs when energy expenditure from athletic training and bodily functions exceeds caloric intake. This imbalance results in declines in athletic performance and increases the risk of injury. Relative energy deficiency in sport (REDs) is a condition that occurs when the energy deficit is severe enough to cause alterations to metabolic rate, menstrual function, immune function, bone health, protein synthesis, and cardiovascular function. Many athletes, particularly those competing in endurance, aesthetic, or weight-class sports, are adversely impacted by this condition.

OBJECTIVES

This study aims to determine the prevalence of LEA and REDs among athletes and present the first secondary analysis of the impacts of these phenomena on sports performance and risk of injury.

METHODS

This systematic review was registered on PROSPERO (CRD42023469253). Literature searches were performed following PRISMA guidelines using PubMed, Embase, and Cochrane online databases. Inclusion criteria were articles discussing the prevalence of LEA or REDs, the impact of LEA or REDs on athletic performance, or the impact of LEA or REDs EA on injury.

RESULTS

A total of 59 studies met the inclusion criteria for this meta-analysis, and 2737 of 6118 athletes (44.7%) in 46 different studies were determined to have LEA, including 44.2% of female athletes and 49.4% of male athletes. In addition, 460 of 730 athletes (63.0%) in eight different studies were determined to be at risk of REDs. Athletes with LEA were found to have decreased run performance, training response, endurance performance, coordination, concentration, judgment, explosive power, and agility relative to athletes with normal energy availability, as well as an increased likelihood of absence from training due to illness. Studies had mixed results as to whether LEA increased the risk of injury in general. However, most studies concluded that athletes with LEA have impaired bone health and a higher risk of bone stress injuries.

DISCUSSION

To our knowledge, this is the first systematic review analyzing the impacts of LEA and REDs on athletic performance and risk of injury. Due to the high estimated prevalence of LEA among athletes, coaches may want to consider employing surveys such as the low energy availability in females questionnaire (LEAF-Q) to identify athletes at risk for LEA, as early identification and correction of LEA can prevent the development of symptoms of REDs, reduce the risk of impaired bone health and bone stress injuries, and help athletes optimize the performance benefits from their training.

Are Sub-elite Athletes at Higher Risk of Eating Disorders, Exercise Addiction, Depression, and Low Energy Availability Compared With Elite Athletes?

OBJECTIVE

The main objective of this study was to investigate the risk of eating disorders, exercise addiction, depression, and low energy availability (LEA) in Danish female and male elite compared with sub-elite athletes.

DESIGN

A cross-sectional study.

SETTING

An online survey.

PARTICIPANTS

A total of 410 elite athletes (mean age 20.1 years, 51% females) and 206 sub-elite athletes (mean age 21.3 years, 52% females) from 15 different sports.Assessment of Risk Factors: Eating Disorders, exercise addiction, depression, and LEA.

MAIN OUTCOME MEASURES

The Sick Control, One Stone (6.5 kg), Fat, Food, the Eating Disorder Examination-Questionnaire, the Exercise Addiction Inventory, the Major Depression Inventory, and the Low Energy Availability in Females Questionnaire or the Low Energy Availability in Males Questionnaire.

RESULTS

We found that more female sub-elite athletes compared with elite athletes had risk of eating disorders (EDs) (37.4% vs 23.4%; P < 0.012) and the same was found for males (23.2% vs 10.4%; P = 0.005). More athletes with risk of EDs had risk of exercise addiction (12.8 vs 5.4%, P = 0.006), depression (27.3 vs 4.2%, P < 0.001), and LEA (females 55.1 vs 40.7%, P = 0.024, and males 29.4 vs 13.7%, P = 0.036, respectively) compared with athletes without risk of EDs.

CONCLUSIONS

Sub-elite athletes have a higher risk of eating disorders compared with elite athletes. Regular screening of ED symptoms and associated conditions in elite and especially sub-elite athletes may ensure early identification.

Society for endocrinology guideline for understanding, diagnosing and treating female hypogonadism

Female hypogonadism (FH) is a relatively common endocrine disorder in women of premenopausal age, but there are significant uncertainties and wide variation in its management. Most current guidelines are monospecialty and only address premature ovarian insufficiency (POI); some allude to management in very brief and general terms, and most rely upon the extrapolation of evidence from the studies relating to physiological estrogen deficiency in postmenopausal women. The Society for Endocrinology commissioned new guidance to provide all care providers with a multidisciplinary perspective on managing patients with all forms of FH. It has been compiled using expertise from Endocrinology, Primary Care, Gynaecology and Reproductive Health practices, with contributions from expert patients and a patient support group, to help clinicians best manage FH resulting from both POI and hypothalamo-pituitary disorders, whether organic or functional.

Body Mass Management Practices of Olympic Weightlifting Athletes

This study explored the body mass (BM) management practices among competitive male and female Olympic weightlifting athletes, hypothesizing that athletes compete in lighter weight categories than their habitual training weight (i.e., making weight). Utilizing a validated, anonymous survey, data were collected from 149 Olympic weightlifting athletes (>18 years; female = 94). The survey comprised five sections: demographics, training/competition history, weight history, source of influence, and BM management practices. The prevalence, magnitude, and methods employed for BM management were analyzed with subgroup analysis using one-way analysis of variance. Post hoc testing including Spearman's rho and chi-square analysis was completed when a significant effect was found. Three quarters (76%) of athletes acknowledged using chronic weight loss and/or acute weight loss strategies to make weight. Usual BM loss (2%-3%) in the week before competition was within recommended guidelines. Gradual dieting, fluid restriction, and low food weight, high-calorie options were the most commonly used BM management strategies. Female athletes were more likely to use gradual dieting (p = .043; r = .104) and were less likely to increase their exercise (p = .046; r = -.105) and utilize fasting (p = .038; r = .05) compared with their male counterparts. Women further identified dietitians/nutritionists (p = .006; r = .022) as a highly influential source of information. This research offers new insights into the BM management practices of Olympic weightlifting athletes, identifying that the majority of athletes compete at a BM lighter than their habitual training weight, achieved using a range of chronic weight loss and acute weight loss strategies.

Low energy availability surrogates are associated with Relative Energy Deficiency in Sport outcomes in male athletes

OBJECTIVES

To determine the association between surrogates of low energy availability (EA) and proposed health and performance outcomes of Relative Energy Deficiency in Sport (REDs) in a clinical sample of adolescent and young adult male athletes.

METHODS

Male athletes ages 15-30 years presenting to a sports medicine clinic at two tertiary care centres were invited to complete a survey about athlete health and well-being. Participants were divided into low EA and adequate EA groups based on survey responses. The associations between low EA and REDs outcomes were evaluated using χ2 tests and ORs were calculated using binomial logistic regression (significance: p<0.05).

RESULTS

Low EA was associated with increased frequency of self-reported immunological, metabolic, psychological, cardiovascular and gastrointestinal dysfunction; reduced endurance performance, response to training, judgement, coordination and muscle strength; and increased irritability and depression. Low EA athletes were more likely to have self-reported cardiovascular dysfunction (OR 2.87, 95% CI 1.56 to 5.26) and psychological illness (OR 3.23, 95% CI 1.91 to 5.41), decreased training response (OR 2.64, 95% CI 1.38 to 5.03) and endurance performance (OR 2.26, 95% CI 1.13 to 4.52) and were less likely to have self-reported gonadal dysfunction (OR 0.49, 95% CI 0.30 to 0.81), than adequate EA athletes (p<0.05).

CONCLUSIONS

Low EA surrogates are associated with many adverse health outcomes and performance effects of REDs in male athletes. More prospective REDs research in males is needed to improve various aspects of REDs screening in young male athletes.

How the Menstrual Cycle Can Be Utilized During Sports Training, Performance, and Recovery through Wearable Technology: A Narrative Review for Researchers, Physicians, Coaches, and Athletes

The menstrual cycle (MC) serves as a vital indicator of overall health and metabolic function, regulated by the hypothalamic-pituitary axis and involving a complex interplay of hormones. Understanding these hormonal dynamics is crucial for deciphering an individual's physiological status and performance potential, particularly in athletes. Studies regarding the MC's impact on athletic performance and training often lack inclusivity, standardized methodologies, and inconsistent biological definitions, hindering comprehensive conclusions. Moreover, societal inequalities contribute to the underrepresentation of female athletes in research, exacerbating the lack of understanding regarding female physiology in sports medicine. Leveraging wearable technology presents a promising avenue for both tracking MCs and optimizing athletic training/recovery. Wearables offer real-time monitoring of biometrics that often correlate with hormonal fluctuations, and lifestyle trends (diet, sleep, stress) aiding in personalized training schedules and performance optimization. Integrating data collected by MC dynamics and wearable technology into athletic training has the potential to decrease the generally perceived negative impacts MC has on athletic performance. Addressing gaps in research methodologies and promoting awareness among athletes, coaches, and healthcare professionals are essential steps toward maximizing the potential of MC-informed training strategies.

Are we asking the right questions? Female athletes' perspectives on the menstrual cycle in sport

BACKGROUND

Menstrual cycle (MC) research employing qualitative and quantitative methods has recently increased in athlete populations. A move towards a participant-centered approach to help formulate questions that align with practitioners' and stakeholders' priorities in the sport environment is needed. Therefore, our study aims were to 1) understand what athletes feel is important to consider regarding their MC in sport, and 2) provide practical recommendations for coaches and practitioners to support a positive sport culture around the MC.

METHODS

Participants were Canadian female athletes competing at national and international levels. Team (n = 10) and individual (n = 10) sport athletes (median age 23 years) shared their experiences and values in one-on-one semi-structured interviews.

RESULTS

Three main theories were identified by constructive grounded theory analyses: 1) training and performance, 2) culture, and 3) health. Athletes expressed a desire for symptom management strategies and more evidence on MC training periodization to optimize performance. Key determinants in creating a positive culture included communication and feeling supported. Athletes also expressed challenges in balancing health with performance and felt ill-informed on how hormonal contraceptives could potentially impact performance. Practical recommendations included 1) addressing individualized, context-specific symptom impacts on the athlete's sport demands, 2) using a group-based approach to initiate MC communication topics and, 3) designate female health point-of-contact staff to facilitate MC information.

CONCLUSION

Future research should continue to evaluate MC impacts on training and performance and study designs should include participants who are using hormonal contraceptives. Coaches and sport practitioners should prioritize female athlete health alongside performance goals.

Plant-Based Dietary Protein Is Associated with Lower Metabolic Syndrome Risk in Division III Female Athletes: A Pilot Study

BACKGROUND

College athletes are often overlooked for metabolic syndrome (MetS), as their increased physical activity is assumed to reduce their disease risk. However, energy or macronutrient imbalance has been shown to increase risk independent of activity. The purpose of this investigation was to assess the current dietary habits of Division III female athletes and determine their associations with body composition and MetS. Secondly, we sought to determine whether dietary intake and dietary protein source (i.e., animal- and plant-based, ABP and PBP) and quality were associated with MetS, as estimated by the Simple Method for Quantifying Metabolic Syndrome (siMS) score and the siMS risk score, and whether protein pacing was associated with body composition in Division III female athletes.

METHODS

Stepwise linear regression determined whether age (years), body mass (kg), body mass index (BMI; kg/m2), ABP (g/d), PBP (g/d), ABP:PBP, ratio of high-quality to low-quality ABP (ABP QR), relative energy intake (kcal/kg/d), and relative protein, carbohydrate, and fat intake (g/kg/d) were predictors of siMS score and siMS risk score.

RESULTS

Twenty-five athletes (19.6 ± 1.3 years; 65.9 ± 7.0 kg; 23.5 ± 2.0 kg/m2; ABP 71.7 ± 28.2 g/d; PBP 30.0 ± 12.2 g/d) were included in the analyses. An inverse relationship was observed between PBP and the siMS score (F1, 22 = 5.498, p = 0.028) and siMS risk score (F1, 22 = 7.614, p = 0.011). The models explained 20% and 26% of the variance in siMS score and siMS risk score, respectively.

CONCLUSIONS

PBP was associated with lower MetS risk in Division III female athletes, while ABP, regardless of quality, was unrelated. These associations were independent of physical activity in this cohort of Division III female athletes.

The Race Within a Race: Starting Together, Finishing Apart

Every four years the world's best athletes come together to compete in the Olympic games, electrifying audiences with incredible feats of speed, strength, endurance and skill as personal best performances and new records are set. However, the exceptional talent that underpin such performances is incomprehensible to most casual observers who often cannot appreciate how unique these athletes are. In this regard, endurance running, specifically the marathon, a 42.195 km foot race, provides one of the few occasions in sport outside of Olympic, world and national competitions, that permits sport scientists and fans alike to directly compare differences in the physiology between recreational and elite competitors. While these individuals may all cover the same distance, on the same course, on the same day - their experience and the physiological and psychological demands placed upon them are vastly different. There is, in effect, a "race within a race". In the current review we highlight the superior physiology of the elite endurance athlete, emphasizing the gap between elite competitors and well-trained, but less genetically endowed athletes. We draw attention to a range of inconsistencies in how current sports science practices are understood, implemented, and communicated in terms of the elite and not-so-elite endurance athlete.

Psychiatric risk factors in Formula One and the importance of integrating mental health into driver science

Formula One (F1) racing has recently grown in popularity, extending well beyond its traditional European roots. However, there has been a paucity of scholarly research dedicated to the health of drivers and even less discussion of the prevalence of psychiatric symptoms, risk factors, and types of psychopathology in F1. This is notable given advancements in sports psychiatry and evidence of psychiatric disorders emerging across other sports. Accordingly, this perspective paper details the physiological conditions in F1 and the socioenvironmental pressures that a driver may encounter during their career, including heat stress, weight restrictions, harassment, and other factors. These extreme physiological and psychological stressors, both in racing and non-racing environments, alongside sport-specific psychosocial pressures, may cause HPA axis dysregulation and other issues in drivers, heightening vulnerabilities for mental health concerns. Additionally, F1 is still affected by stigmatizing attitudes and regressive sociocultural norms, which could inhibit progress toward promoting sustainable wellbeing. Consequently, drivers may be at risk for mental disorder and a decrease in overall health and wellbeing. Against this background, we thereby recommend mental health programs and regulatory actions that could better address these challenges and promote mental wellbeing across F1.

Low Energy Availability Risk Is Associated with Anxiety in Female Collegiate Athletes

This study investigated the association between the risk of low energy availability, disordered eating, and anxiety in collegiate female athletes. Female athletes (n = 115) completed questionnaires that assessed disordered eating (Disordered Eating Screen for Athletes, DESA-6; and the Eating Disorder Examination Questionnaire Short, EDE-QS), anxiety (Generalized Anxiety Disorder-7) and the risk of low energy availability (Low Energy Availability in Females Questionnaire; LEAF-Q). The athletes were 19.9 ± 0.1 years old and presented with no anxiety (14.8%), mild (33.0%), moderate (24.3%), and severe (27.8%) anxiety. The EDE-QS scores revealed that 22.6% of the participants had a high risk of an eating disorder, while the DESA-6 scores revealed that 31.3% of the participants scored positive for a risk of disordered eating. The LEAF-Q total scores revealed that 68.7% of the participants were at risk of low energy availability. Increased GAD-7 scores were associated (p < 0.001) with measures of disordered eating (EDE-QS and DESA-6) and the risk of low energy availability (LEAF-Q total score). Non-parametric partial correlations demonstrated that anxiety (increased GAD-7 scores) correlated with the risk of low energy availability (increased LEAF-Q total scores) while controlling for eating disorder scores (EDE-QS) (r (112) = 0.353, p < 0.001), or while controlling for the risk of disordered eating (DESA-6 scores) (r (112) = 0.349, p < 0.001). In female collegiate athletes, both disordered eating and the risk of low energy availability were positively associated with increased anxiety.

Prevalence of physiological and perceptual markers of low energy availability in male academy football players: a study protocol for a cross-sectional study

Low energy availability (LEA) is a core feature of the female athlete triad and relative energy deficiency in sport (REDs). LEA underpins multiple adverse health and performance outcomes in various athletic populations, including weight category, endurance and aesthetic sports. Recent reports suggest LEA is highly prevalent in female football, volleyball and netball, with little known on male team-sport athletes. Therefore, the study aims to identify the prevalence of LEA among male academy football players (16-23 years), using surrogate markers that align with the International Olympic Committee REDs Clinical Assessment Tool-Version 2. A cross-sectional study design will be used with physiological and perceptual markers of LEA measured. The study will seek to recruit 355 players to complete several online questionnaires believed to be associated with LEA, measured using a 24-hour food and activity diary. Of the 355 players, a subsample (n=110) will complete an additional 3-day food and activity diary, provide a venous blood sample to measure levels of total testosterone and free triiodothyronine, and have resting metabolic rate (RMR) measured to determine RMRratio. The prevalence of LEA will be determined using the low (<30 kcal·kgFFM-1·day-1) domain of energy availability and divided by the total number of participants. Descriptive statistics will be used to summarise the whole group and difference status of energy availability (eg, low, reduced, optimal, high). A univariable and multivariable binary logistic regression analysis will be modelled to assess the association of various surrogate markers with the presence of LEA.

Energy availability and its association with health-related outcomes among national athletes at risk of relative energy deficiency in sports (REDs)

ABSTRACT

Background

Low energy availability (LEA) occurs when athletes' energy intake fails to match the energy expended during exercise, resulting in insufficient energy to support essential functions for optimal health, a condition known as relative energy deficiency in sports (REDs).

Objective

This study aims to explore the prevalence of LEA among Malaysian national athletes and its associations with health-related outcomes.

Methods

A total of 43 athletes (51.2% males, aged 18-40) identified previously as having moderate or high risk of REDs through a questionnaire underwent comprehensive clinical assessments. Resting metabolic rate (RMR) was measured using indirect calorimetry, with an RMR ratio of <0.90 indicating LEA. Weight and height were measured, and fasting blood samples were analysed for ferritin, free triiodothyronine (fT3), follicle-stimulating hormone (FSH), luteinising hormone (LH), estradiol (female athletes) and testosterone (male athletes). Bone mineral density (BMD) of the lumbar spine and total left hip, as well as body composition, were measured using dual-energy X-ray absorptiometry (DXA).

Results

Out of the 43 athletes, 12 showed evidence of LEA, exhibiting at least one of the following characteristics: low estradiol levels (87.5%), low testosterone (75.0%), low fT3 (66.7%), low LH (58.3%), low FSH (58.3%), low ferritin (25.0%) and low BMD (8.3%). Notably, fT3, estradiol and testosterone were significant predictors for LEA.

Conclusions

A low but noteworthy incidence of LEA among Malaysian national athletes was associated with hormone imbalances. Awareness about LEA among athletes and sports personnel is essential for early detection and appropriate intervention.

The Association Between Menstrual Cycle Phase, Menstrual Irregularities, Contraceptive Use and Musculoskeletal Injury Among Female Athletes: A Scoping Review

BACKGROUND

The influence of menstrual cycle phases (MCPs), menstrual irregularities (MI) and hormonal contraceptive (HC) use on injury among female athletes has been scrutinised. Existing systematic reviews investigating the effect of exposures affecting the endogenous reproductive hormone status on sporting injuries are limited in terms of the types of studies included and injuries investigated.

OBJECTIVE

This scoping review aims to summarise the coverage of the literature related to the extent, nature and characteristics of the influence of MCP, MI and HC use on musculoskeletal injuries among athletes. It also aims to summarise key concepts and definitions in the relevant literature. Observational and experimental studies investigating the effect of MCP, MI, and HC on musculoskeletal injuries among female individuals of reproductive age were included. Studies specifically stating pregnant women, perimenopausal/postmenopausal athletes, or those using medication (other than HC) that affects reproductive hormone profiles or the musculoskeletal system were excluded.

METHODS

This scoping review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping reviews and JBI scoping review guidelines. Published and unpublished studies were sourced from several databases and resources. Initial keywords used included terms related to "menstrual cycle", "hormonal contraception" and "injury." Titles and abstracts of identified citations were screened independently and assessed for eligibility by two independent reviewers. Data from the included studies were extracted using a standard data extraction form.

RESULTS

The search yielded 10,696 articles, of which 96 met the eligibility criteria. Most studies investigated MI (77%), and 49% included MCP as a contributing injury risk factor. Publications have increased over the last two decades. Collectively, only 16% of research has been conducted in Africa, Asia and Oceania. There were no studies from South America. Seventy-five percent of the studies investigated individual versus team (25%) sport athletes. Most studies only investigated elite or professional (n = 24; 25%) level athletes. The definitions of injury, eumenorrhea and MI differ vastly among studies. Regarding MI, most studies (69%) investigated secondary amenorrhea, followed by oligomenorrhea (51%) and primary amenorrhea (43%). Concerning HC, the influence of oral contraceptive pills was mainly investigated.

CONCLUSIONS

Research related to MCP, MI and HC as contributing musculoskeletal injury risk factors is increasing; however, several gaps have been identified, including research from countries other than North America and Europe, the study population being non-professional/elite level athletes, athletes participating in team sports and specific injuries related to MCP, MI and HC, respectively. Differences in methodology and terminology of injury, MCP and MI hinder comparative summative research, and future research should consider current published guidelines during the study design. Identifying barriers to following standard guidelines or research investigating the most practical yet accurate methods to investigate the influence of MCP on musculoskeletal health might yield valuable insights for future research designs.

CLINICAL TRIAL REGISTRATION

Scoping review registration number: Open Science Framework ( https://doi.org/10.17605/OSF.IO/5GWBV ).

Energy expenditure of international female rugby union players during a major international tournament: a doubly labelled water study

The purpose of this study was to quantify the total energy expenditure (TEE) of international female rugby union players. Fifteen players were assessed over 14 days throughout an international multi-game tournament, which represented two consecutive one-match microcycles. Resting metabolic rate (RMR) and TEE were assessed by indirect calorimetry and doubly labelled water, respectively. Physical activity level (PAL) was estimated (TEE:RMR). Mean RMR, TEE, and PAL were 6.60 ± 0.93 MJ·day-1 (1578 ± 223 kcal·day-1), 13.51 ± 2.28 MJ·day-1 (3229 ± 545 kcal·day-1), and 2.0 ± 0.3 AU, respectively. There was no difference in TEE (13.74 ± 2.31 (3284 ± 554 kcal·day-1) vs. 13.92 ± 2.10 MJ·day-1 (3327 ± 502 kcal·day-1); p = 0.754), or PAL (2.06 ± 0.26 AU vs. 2.09 ± 0.23 AU; p = 0.735) across microcycles, despite substantial decreases in training load (total distance: -8088 m, collisions: -20 n, training duration: -252 min). After correcting for body composition, there was no difference in TEE (13.80 ± 1.74 (3298 ± 416 adj. kcal·day-1) vs. 13.16 ± 1.97 (3145 ± 471 adj. kcal·day-1) adj. MJ·day-1, p = 0.190), RMR (6.49 ± 0.81 (1551 ± 194 adj. kcal·day-1) vs. 6.73 ± 0.83 (1609 ± 198 adj. kcal·day-1) adj. MJ·day-1, p = 0.633) or PAL (2.15 ± 0.14 vs. 1.87 ± 0.26 AU, p = 0.090) between forwards and backs. For an injured participant (n = 1), TEE reduced by 1.7 MJ·day-1 (-401 kcal·day-1) from pre-injury. For participants with illness (n = 3), TEE was similar to pre-illness (+0.49 MJ·day-1 (+117 kcal·day-1)). The energy requirements of international female rugby players were consistent across one-match microcycles. Forwards and backs had similar adjusted energy requirements. These findings are critical to inform the dietary guidance provided to female rugby players.

Self-Reported Menstrual Health, Symptomatology, and Perceived Effects of the Menstrual Cycle for Elite Junior and Senior Football Players

PURPOSE

To describe the self-reported menstrual health, symptomatology, and perceived effects of the menstrual cycle on athletic performance for national and international Australian football (soccer) players.

METHODS

Players from national and domestic teams were invited to complete an online questionnaire regarding menstrual health, use of hormonal contraceptives (HCs), negative symptomatology, and perceived disruption of the menstrual cycle to performance. Descriptive statistics and binomial regressions with odds ratios (OR) were used to report the relationship of menstrual-related variables with perceived performance disruption.

RESULTS

A total of 199 players (20.9 [5.1] y) completed the questionnaire, with 18% of players reporting using HCs. One primary amenorrhea case was detected, and 26% of players reported menarche at age ≥15 years. For non-HC users, the prevalence of secondary amenorrhea was 2%, oligomenorrhea was 19%, and heavy menstrual bleeding was 11%. Ninety-seven percent of players reported experiencing physical or affective menstrual symptoms (5 [1.3] per player), and 40% of all players reported that menstrual symptoms impacted their ability to work, study, train, or compete. Furthermore, 40% of players perceived their training or performance to be disrupted by the menstrual cycle. Increasing number of menstrual symptoms (OR = 1.43; 95% CI, 1.28-1.62; P < .001), heavy menstrual bleeding (OR = 12.73; 95% CI, 3.4-82.8; P < .001), and pelvic pain (OR = 3.40; 95% CI, 1.7-7.2; P < .001) increased the likelihood of perceiving the menstrual cycle to disrupt performance.

CONCLUSION

Heavy menstrual bleeding and HC use were low among this cohort of national and international footballers, whereas amenorrhea and oligomenorrhoea were comparable with other football populations. Nearly all players reported menstrual symptoms, and increased symptomatology was associated with greater perceived effects on performance.

The brain-body energy conservation model of aging

Aging involves seemingly paradoxical changes in energy metabolism. Molecular damage accumulation increases cellular energy expenditure, yet whole-body energy expenditure remains stable or decreases with age. We resolve this apparent contradiction by positioning the brain as the mediator and broker in the organismal energy economy. As somatic tissues accumulate damage over time, costly intracellular stress responses are activated, causing aging or senescent cells to secrete cytokines that convey increased cellular energy demand (hypermetabolism) to the brain. To conserve energy in the face of a shrinking energy budget, the brain deploys energy conservation responses, which suppress low-priority processes, producing fatigue, physical inactivity, blunted sensory capacities, immune alterations and endocrine 'deficits'. We term this cascade the brain-body energy conservation (BEC) model of aging. The BEC outlines (1) the energetic cost of cellular aging, (2) how brain perception of senescence-associated hypermetabolism may drive the phenotypic manifestations of aging and (3) energetic principles underlying the modifiability of aging trajectories by stressors and geroscience interventions.

Measurement of energy availability in highly trained male endurance athletes and examination of its associations with bone health and endocrine function

PURPOSE

Despite the introduction of Relative Energy Deficiency in Sport (RED-s) in 2014, there is evidence to suggest that male endurance athletes still present with a high prevalence of low energy availability (LEA). Previous findings suggest that energy availability (EA) status is strongly correlated with impairments in endocrine function such as reduced leptin, triiodothyronine (T3), and insulin, and elevated bone loss. This study aimed to report the current EA status, endocrine function and bone health of highly trained Irish male endurance athletes.

METHODS

In this cross-sectional study, participants (n = 3 triathletes; n = 10 runners) completed a 7-day testing period during the competition season using lab-based measures, to ascertain EA status, hormone level and rates of bone metabolism. Serum blood samples were obtained to assess hormone levels and markers of bone metabolism.

RESULTS

Mean EA was < 30 kcal/kg lean body mass (LBM)/day in 76.9% of athletes. There was a strong association between LEA and low carbohydrate intake, and lower LBM. Mean levels of insulin, IGF-1 and leptin were significantly lower than their reference ranges. Elevated mean concentrations of β-CTX and a mean P1NP: β-CTX ratio < 100, indicated a state of bone resorption.

CONCLUSION

The EA level, carbohydrate intake, hormone status and bone metabolism status of highly trained male endurance athletes are a concern. Based on the findings of this study, more frequent assessment of EA across a season is recommended to monitor the status of male endurance athletes, in conjunction with nutritional education specific to EA and the associated risks.

Dietary intake, energy availability, and power in men collegiate gymnasts

Introduction

The purpose was to examine the prevalence of low energy availability (LEA), explore dietary behaviors in men collegiate gymnasts (n = 14), and investigate the relationships between energy availability (EA), body composition, and plyometric performance.

Methods

Body composition was measured using air displacement plethysmography. Lower- and upper-body peak power (PWRpeak) and modified reactive strength index (RSImod) were calculated from countermovement jump (CMJ) and plyometric push-up (PP) assessments. Energy expenditure was tracked over 3 days, while daily energy and macronutrient intake were recorded. EA was calculated and used to categorize athletes into LEA and non-LEA groups. Pearson correlation coefficients were used to examine relationships between EA, body composition, and performance metrics.

Results

85.7% of athletes (n = 12) exhibited LEA (20.98 ± 5.2 kcals/kg FFM), with non-LEA athletes (n = 2) marginally surpassing the <30 kcal/kg of fat-free mass (FFM) threshold (30.58 ± 0.2 kcals/kg FFM). The cohort (n = 14) consumed insufficient energy (30.5 ± 4.5 kcal/kg/day) and carbohydrates (3.7 ± 1.1 g/kg/day), resulting in LEA (22.36 ± 5.9 kcal/kg/FFM). EA was not correlated with body composition or performance metrics.

Discussion

A high prevalence of LEA may exist in men gymnasts, largely due to a low relative energy and carbohydrate intake.

Does Relative Energy Deficiency in Sport (REDs) Syndrome Exist?

Relative energy deficiency in sport (REDs) is a widely adopted model, originally proposed by an International Olympic Committee (IOC) expert panel in 2014 and recently updated in an IOC 2023 consensus statement. The model describes how low energy availability (LEA) causes a wide range of deleterious health and performance outcomes in athletes. With increasing frequency, sports practitioners are diagnosing athletes with "REDs," or "REDs syndrome," based largely upon symptom presentation. The purpose of this review is not to "debunk" REDs but to challenge dogmas and encourage rigorous scientific processes. We critically discuss the REDs concept and existing empirical evidence available to support the model. The consensus (IOC 2023) is that energy availability, which is at the core of REDs syndrome, is impossible to measure accurately enough in the field, and therefore, the only way to diagnose an athlete with REDs appears to be by studying symptom presentation and risk factors. However, the symptoms are rather generic, and the causes likely multifactorial. Here we discuss that (1) it is very difficult to isolate the effects of LEA from other potential causes of the same symptoms (in the laboratory but even more so in the field); (2) the model is grounded in the idea that one factor causes symptoms rather than a combination of factors adding up to the etiology. For example, the model does not allow for high allostatic load (psychophysiological "wear and tear") to explain the symptoms; (3) the REDs diagnosis is by definition biased because one is trying to prove that the correct diagnosis is REDs, by excluding other potential causes (referred to as differential diagnosis, although a differential diagnosis is supposed to find the cause, not demonstrate that it is a pre-determined cause); (4) observational/cross-sectional studies have typically been short duration (< 7 days) and do not address the long term "problematic LEA," as described in the IOC 2023 consensus statement; and (5) the evidence is not as convincing as it is sometimes believed to be (i.e., many practitioners believe REDs is well established). Very few studies can demonstrate causality between LEA and symptoms, most studies demonstrate associations and there is a worrying number of (narrative) reviews on the topic, relative to original research. Here we suggest that the athlete is best served by an unbiased approach that places health at the center, leaving open all possible explanations for the presented symptoms. Practitioners could use a checklist that addresses eight categories of potential causes and involve the relevant experts if and when needed. The Athlete Health and Readiness Checklist (AHaRC) we introduce here simply consists of tools that have already been developed by various expert/consensus statements to monitor and troubleshoot aspects of athlete health and performance issues. Isolating the purported effects of LEA from the myriad of other potential causes of REDs symptoms is experimentally challenging. This renders the REDs model somewhat immune to falsification and we may never definitively answer the question, "does REDs syndrome exist?" From a practical point of view, it is not necessary to isolate LEA as a cause because all potential areas of health and performance improvement should be identified and tackled.

Relative Energy Deficiency in Sport (REDs): Endocrine Manifestations, Pathophysiology and Treatments

Research on lean, energy-deficient athletic and military cohorts has broadened the concept of the Female Athlete Triad into the Relative Energy Deficiency in Sport (REDs) syndrome. REDs represents a spectrum of abnormalities induced by low energy availability (LEA), which serves as the underlying cause of all symptoms described within the REDs concept, affecting exercising populations of either biological sex. Both short- and long-term LEA, in conjunction with other moderating factors, may produce a multitude of maladaptive changes that impair various physiological systems and adversely affect health, well-being, and sport performance. Consequently, the comprehensive definition of REDs encompasses a broad spectrum of physiological sequelae and adverse clinical outcomes related to LEA, such as neuroendocrine, bone, immune, and hematological effects, ultimately resulting in compromised health and performance. In this review, we discuss the pathophysiology of REDs and associated disorders. We briefly examine current treatment recommendations for REDs, primarily focusing on nonpharmacological, behavioral, and lifestyle modifications that target its underlying cause-energy deficit. We also discuss treatment approaches aimed at managing symptoms, such as menstrual dysfunction and bone stress injuries, and explore potential novel treatments that target the underlying physiology, emphasizing the roles of leptin and the activin-follistatin-inhibin axis, the roles of which remain to be fully elucidated, in the pathophysiology and management of REDs. In the near future, novel therapies leveraging our emerging understanding of molecules and physiological axes underlying energy availability or lack thereof may restore LEA-related abnormalities, thus preventing and/or treating REDs-related health complications, such as stress fractures, and improving performance.

Changes in hormonal profiles during competition preparation in physique athletes

PURPOSE

Physique athletes engage in rigorous competition preparation involving intense energy restriction and physical training to enhance muscle definition. This study investigates hormonal changes and their physiological and performance impacts during such preparation.

METHODS

Participants included female (10 competing (COMP) and 10 non-dieting controls (CTRL)) and male (13 COMP and 10 CTRL) physique athletes. COMP participants were tested 23 weeks before (PRE), one week before (MID), and 23 weeks after the competition (POST). Non-dieting CTRL participants were tested at similar intervals. Measurements included body composition (DXA), muscle cross-sectional area (ultrasound), energy availability (EA) derived by subtracting exercise energy expenditure (EEE) from energy intake (EI) and dividing by fat-free mass (FFM), muscle strength, and various serum hormone concentrations (ACTH, cortisol, estradiol, FSH, IGF-1, IGFBP-3, insulin, and free and total testosterone and SHBG).

RESULTS

During the diet, EA (p < 0.001), IGF-1 (p < 0.001), IGFBP-3 (p < 0.01), and absolute muscle strength (p < 0.01-0.001) decreased significantly in both sexes in COMP. Decreases in IGF-1 were also associated with higher loss in FFM. In males, testosterone (p < 0.01) and free testosterone (p < 0.05) decreased, while SHBG (p < 0.001) and cortisol (p < 0.05) increased. Insulin decreased significantly only in males (p < 0.001). Mood disturbances, particularly increased fatigue in males (p < 0.05), highlighted the psychological strain of competition preparation. All these changes were restored by increased EA during the post-competition recovery period.

CONCLUSION

Significant reductions in IGF-1 and IGFBP-3 during competition preparation may serve as biomarkers for monitoring physiological stress. This study offers valuable insights into hormonal changes, muscle strength, and mood state during energy-restricted intense training.

Hypothalamic-pituitary-ovarian axis suppression is common among women during US Army Basic Combat Training

OBJECTIVE

Less than half of servicewomen report loss of menses during initial military training. However, self-reported menstrual status may not accurately reflect hypothalamic-pituitary-ovarian (HPO) axis suppression and may underestimate reproductive health consequences of military training. Our aim was to characterise HPO axis function during US Army Basic Combat Training (BCT) in non-hormonal contraceptive-using women and explore potential contributors to HPO axis suppression.

METHODS

In this 10-week prospective observational study, we enrolled multi-ethnic women entering BCT. Trainees provided daily first-morning voided urine, and weekly blood samples during BCT. Urinary luteinising hormone, follicle stimulating hormone, and metabolites of estradiol and progesterone were measured by chemiluminescent assays (Siemens Centaur XP) to determine hormone patterns and luteal activity. We measured body composition, via dual-energy X-ray absorptiometry, at the beginning and end of BCT.

RESULTS

Trainees (n=55) were young (mean (95% CI): 22 (22, 23) years) with average body mass index (23.9 (23.1, 24.7) kg/m2). Most trainees (78%) reported regular menstrual cycles before BCT. During BCT, 23 (42%) trainees reported regular menses. However, only seven trainees (12.5%) had menstrual cycles with evidence of luteal activity (ELA) (ie, presumed ovulation), all with shortened luteal phases. 41 trainees (75%) showed no ELA (NELA), and 7 (12.5%) were categorised as indeterminant. Overall, women gained body mass and lean mass, but lost fat mass during BCT. Changes in body mass and composition appear unrelated to luteal activity.

CONCLUSIONS

Our findings reveal profound HPO axis suppression with NELA in the majority of women during BCT. This HPO axis suppression occurs among women who report normal menstrual cycles.

Are female athlete specific health considerations being assessed and addressed in preparticipation examinations? A scoping review and proposed framework

BACKGROUND

Preparticipation examinations (PPEs) are unstandardized screening tools routinely used to collect an athlete's baseline health information prior to the start of a new competitive season. However, many PPEs include minimal and often nonspecific questions related to the health concerns of female athletes. A lack of female athlete specific health questions could result in missed red flags and subsequent injury or illness. As such, the objectives of this scoping review were to (a) determine what female athlete specific health questions currently exist in PPEs in the scientific literature to prevent injury and illness, and (b) map the results against the health domains outlined in the International Olympic Committee (IOC) consensus statement supplement on the female athlete.

METHODS

We searched Embase, Scopus, CINAHL, Medline Ovid, and SPORTDiscus from inception to December 2022. Any study with female athlete specific health PPE questions or recommendations for questions (i.e., menstrual health, eating habits, musculoskeletal health, etc.) was included. Three reviewers independently screened titles and abstracts, followed by full text articles for eligibility and data extraction, with conflicts resolved by a third-party reviewer. Extracted data were summarized into 3 determined groupings.

RESULTS

Of the 1356 studies screened, 41 were included in this study. Forty studies (98%) included questions/recommendations related to menstrual health. Thirty-one studies (76%) had questions/recommendations concerning disordered eating/eating habits. Twenty-four studies (59%) referred to body weight/image, and 16 studies (39%) referred to musculoskeletal health. No studies included questions on all IOC female athlete health domains.

CONCLUSION

There is currently a gap in female athlete specific health content included in PPEs. A more comprehensive, standardized PPE with a focus on inclusion of female athlete specific health questions and considerations should be developed to improve health and optimal participation of female athletes around the world.

IOC consensus statement on elite youth athletes competing at the Olympic Games: essentials to a healthy, safe and sustainable paradigm

With the pronounced ongoing growth of global youth sports, opportunities for and participation of youth athletes on the world sports stage, including the Olympic Games, are expected to escalate. Yet, adolescence is a vulnerable period of development and inherently dynamic, with non-linear and asynchronous progression of physical, physiological, psychological and social attributes. These non-concurrent changes within and between individuals are accompanied by irregular and unpredictable threats and impediments. Likewise, the evident age-based criteria and conventional path for those youth athletes deemed eligible candidates for the Olympic Games are not well or consistently defined. Furthermore, the unstructured and largely varying policies and practices across the sporting International Federations specific to youth participation underscore the need to establish a contemporary universal paradigm that would enable elite youth athletes to navigate an individualised healthy pathway to personal, athletic and sport success. First, we reviewed and summarised key challenges facing elite youth athletes and the relevant evidence fundamental to facilitating and supporting central aspects of health and well-being, while empowering safe, sustainable and positive engagement during athletic and personal advancement and competition. Second, we developed and present a modern elite youth athlete model that emphasises a child-centred, practical framework with corresponding guidelines and recommendations to protect health and well-being while safely and favourably managing international sport competition. Our proposed evidence-informed paradigm will enable and support individualised pathways for healthy, well-rounded and sustainable positive engagement while achieving sport success for youth contending or aiming to compete at world-class international sporting events.

Multi-organ transcriptome atlas of a mouse model of relative energy deficiency in sport

Insufficient energy intake to meet energy expenditure demands of physical activity can result in systemic neuroendocrine and metabolic abnormalities in activity-dependent anorexia and relative energy deficiency in sport (REDs). REDs affects >40% of athletes, yet the lack of underlying molecular changes has been a hurdle to have a better understanding of REDs and its treatment. To assess the molecular changes in response to energy deficiency, we implemented the "exercise-for-food" paradigm, in which food reward size is determined by wheel-running activity. By using this paradigm, we replicated several aspects of REDs in female and male mice with high physical activity and gradually reduced food intake, which results in weight loss, compromised bone health, organ-specific mass changes, and altered rest-activity patterns. By integrating transcriptomics of 19 different organs, we provide a comprehensive dataset that will guide future understanding of REDs and may provide important implications for metabolic health and (athletic) performance.

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.

Original investigation: manipulating energy availability in male endurance runners: a randomised controlled trial

This study investigated the effect of 4 days low energy availability (LEA) on physiological markers and mood states in male endurance runners. Twelve participants (mean (standard deviation); age: 25.8 (3.8) years; fat-free mass (FFM): 52.8 (5.5) kg) completed three 4-day conditions: adequate energy availability (AEA): 45 kcal/kg FFM/day; LEA1: 30 kcal/kg FFM/day; and LEA2: 15 kcal/kg FFM/day, in a randomized order. Participants ran on a treadmill at 65% of V̇O2max until they expended 15 kcal/kg FFM/day of energy. Energy intake was adjusted to achieve the desired energy availability. Pre- and post-measurements of bone turnover, metabolism, testosterone and estradiol (plasma), resting metabolic rate (indirect calorimetry), and mood states (Brunel Mood Scale) were assessed. The results reported a significant decrease in testosterone (condition × time interaction, p = 0.03) occurred on LEA2 (Pre: 23.8 (7.0) nmol/L vs. Post: 20.3 (7.7) nmol/L) compared with AEA (Pre: 22.9 (5.5) nmol/L vs. Post: 23.3 (6.1) nmol/L) or LEA1 (Pre: 23.6 (8.6) nmol/L vs. Post: 20.9 (8.8) nmol/L). Fatigue level significantly increased (condition × time interaction, p = 0.02) in LEA2 (Pre: 3.5 (1.7) vs. Post: 6.5 (2.9)) but did not change in AEA (Pre: 2.8 (1.5) vs. Post: 2.5 (2.7)) or LEA1 (Pre: 2.8(2.4) vs. Post: 2.9 (2.0)). Other measures were unaffected by the interventions. In conclusion, this study suggests that testosterone and fatigue may serve as early indicators of LEA in male runners. However, other physiological markers and mood states appeared largely unaffected, aligning with existing literature indicating minimal disruption of physiological functions during acute LEA in male athletes. Study registration: Australian New Zealand Clinical Trials Registry (Trial No.: 381278).

Body Appreciation is Associated with Emotional Eating in Turkish Female Athletes

It is known that female athletes are at risk for eating disorders. It is thought that factors such as pressure and stress experienced by professional athletes may affect emotional eating and body appreciation. In this context, the aim of this study was to evaluate the emotional eating and body appreciation of professional Turkish female athletes. A total of 265 professional female athletes were categorized according to their sport types and nationality. Emotional eating was found to be higher and body appreciation to be lower in athletes competing at the national level. The results of the hierarchical regression analysis, which included variables such as age, body mass index, professional sports background, national level, and sport type show that the most effective factor in explaining emotional eating in professional female athletes is body appreciation. The present study findings support that professional female athletes are at risk in terms of emotional eating and body appreciation. In addition, emotional eating scores were found to be higher and body appreciation scores were lower in national athletes. Psychological factors such as intense stress and pressure have an impact on the eating behavior and body appreciation of national athletes. These results suggest that athletes should be evaluated by nutritionists, doctors, and psychologists from a multidisciplinary perspective.

An Opinion on the Interpretation of Bone Turnover Markers Following Acute Exercise or Nutrition Intervention and Considerations for Applied Research

It is important for athlete and public health that we continue to develop our understanding of the effects of exercise and nutrition on bone health. Bone turnover markers (BTMs) offer an opportunity to accelerate the progression of bone research by revealing a bone response to exercise and nutrition stimuli far more rapidly than current bone imaging techniques. However, the association between short-term change in the concentration of BTMs and long-term bone health remains ambiguous. Several other limitations also complicate the translation of acute BTM data to applied practice. Importantly, several incongruencies exist between the effects of exercise and nutrition stimuli on short-term change in BTM concentration compared with long-term bone structural outcomes to similar stimuli. There are many potential explanations for these inconsistencies, including that short-term study designs fail to encompass a full remodeling cycle. The current article presents the opinion that data from relatively acute studies measuring BTMs may not be able to reliably inform applied practice aiming to optimize bone health. There are important factors to consider when interpreting or translating BTM data and these are discussed.

The interplay between gut microbiome and physical exercise in athletes

PURPOSE OF REVIEW

The gut microbiome regulates several health and disease-related processes. However, the potential bidirectional relationship between the gut microbiome and physical exercise remains uncertain. Here, we review the evidence related to the gut microbiome in athletes.

RECENT FINDINGS

The effect of physical exercise on the intestinal microbiome and intestinal epithelial cells depends on the type, volume, and intensity of the activity. Strenuous exercise negatively impacts the intestinal microbiome, but adequate training and dietary planning could mitigate these effects. An increase in short-chain fatty acids (SCFAs) concentrations can modulate signaling pathways in skeletal muscle, contributing to greater metabolic efficiency, preserving muscle glycogen, and consequently optimizing physical performance and recovery. Furthermore, higher SCFAs concentrations appear to lower inflammatory response, consequently preventing an exacerbated immune response and reducing the risk of infections among athletes. Regarding dietary interventions, the optimal diet composition for targeting the athlete's microbiome is not yet known. Likewise, the benefits or harms of using probiotics, synbiotics, and postbiotics are not well established, whereas prebiotics appear to optimize SCFAs production.

SUMMARY

The intestinal microbiome plays an important role in modulating health, performance, and recovery in athletes. SCFAs appear to be the main intestinal metabolite related to these effects. Nutritional strategies focusing on the intestinal microbiome need to be developed and tested in well controlled clinical trials.

Beyond Menstrual Dysfunction: Does Altered Endocrine Function Caused by Problematic Low Energy Availability Impair Health and Sports Performance in Female Athletes?

Low energy availability, particularly when problematic (i.e., prolonged and/or severe), has numerous negative consequences for health and sports performance as characterized in relative energy deficiency in sport. These consequences may be driven by disturbances in endocrine function, although scientific evidence clearly linking endocrine dysfunction to decreased sports performance and blunted or diminished training adaptations is limited. We describe how low energy availability-induced changes in sex hormones manifest as menstrual dysfunction and accompanying hormonal dysfunction in other endocrine axes that lead to adverse health outcomes, including negative bone health, impaired metabolic activity, undesired outcomes for body composition, altered immune response, problematic cardiovascular outcomes, iron deficiency, as well as impaired endurance performance and force production, all of which ultimately may influence athlete health and performance. Where identifiable menstrual dysfunction indicates hypothalamic-pituitary-ovarian axis dysfunction, concomitant disturbances in other hormonal axes and their impact on the athlete's health and sports performance must be recognized as well. Given that the margin between podium positions and "losing" in competitive sports can be very small, several important questions regarding low energy availability, endocrinology, and the mechanisms behind impaired training adaptations and sports performance have yet to be explored.

Low energy availability increases immune cell formation of reactive oxygen species and impairs exercise performance in female endurance athletes

INTRODUCTION

The effects of low energy availability (LEA) on the immune system are poorly understood. This study examined the effects of 14 days of LEA on immune cell redox balance and inflammation at rest and in response to acute exercise, and exercise performance in female athletes.

METHODS

Twelve female endurance athletes (age: 26.8 ± 3.4 yrs, maximum oxygen uptake (V˙O2max): 55.2 ± 5.1 mL × min-1 × kg-1) were included in a randomized, single-blinded crossover study. They were allocated to begin with either 14 days of optimal energy availability diet (OEA, 52 ± 2 kcal × kg fat free mass (FFM)-1 × day-1) or LEA diet (22 ± 2 kcal × kg FFM-1 × day-1), followed by 3 days of refueling (OEA) with maintained training volume. Peripheral blood mononuclear cells (PBMCs) were isolated, and plasma obtained at rest before and after each dietary period. The PBMCs were used for analysis of mitochondrial respiration and H2O2 emission and specific proteins. Exercise performance was assessed on cycle by a 20-min time trial and time to exhaustion at an intensity corresponding to ∼110 % V˙O2max).

RESULTS

LEA was associated with a 94 % (P = 0.003) increase in PBMC NADPH oxidase 2 protein content, and a 22 % (P = 0.013) increase in systemic cortisol. LEA also caused an alteration of several inflammatory related proteins (P < 0.05). Acute exercise augmented H2O2 emission in PBMCs (P < 0.001) following both OEA and LEA, but to a greater extent following LEA. LEA also reduced the mobilization of white blood cells with acute exercise. After LEA, performance was reduced in both exercise tests (P < 0.001), and the reduced time trial performance remained after the 3 days of refueling (P < 0.001).

CONCLUSION

14 days of LEA in female athletes increased cortisol levels and had a pronounced effect on the immune system, including increased capacity for ROS production, altered plasma inflammatory proteome and lowered exercise induced mobilization of leukocytes. Furthermore, LEA resulted in a sustained impairment in exercise performance.

Contraception Choice for Female Endurance Athletes: What's Sport Got to Do With It? A Cross-Sectional Survey

BACKGROUND

While there are several prescribed contraceptive methods available, limited evidence exists to guide contraceptive decision-making in the context of endurance sport.

OBJECTIVES

Study objectives were to characterize current and previous use, perceived impacts, and the decision process around contraceptives in endurance athletes.

METHODS

This was an online survey study with female endurance athletes recruited through social media and emails to university/club coaches and sport organizations. Quantitative and qualitative data were analyzed with descriptive statistics and conventional content analysis, respectively.

RESULTS

A total of 323 female endurance athletes participated. Among current contraception users (n = 182), 51% used hormonal intrauterine devices (hIUDs), 29% oral contraceptive pills (OCPs), and 13% nonhormonal IUDs (nhIUDs). hIUD users had the highest perceived positive training (39%) and competition (29%) impacts, citing reduced menstrual bleeding and symptoms as positive side effects. OCP and nhIUD users had higher rates of perceived negative training impacts (OCPs 10%, nhIUDs 30%). For OCP users, 31% reported perceived adverse body composition outcomes and 37% reported negative mood changes. Among nhIUD users, 74% experienced heavier, more irregular menstrual bleeding. Over half of participants were unsure about the impact of their current method on performance. For contraceptive selection, 95% felt that information from physicians was important, yet 32% felt performance was inadequately considered during counseling discussion. Athletes reported less frustration with their contraception choice when counseled in the context of sport.

CONCLUSIONS

This exploratory study quantifies and qualifies the lived experiences of female endurance athletes with contraception. hIUDs were the most currently used and well-tolerated contraceptives among participants. This research offers valuable insights for athletes seeking contraception and looking to optimize both performance and health, along with the healthcare professionals guiding them.

Fat-Free Mass Index in Sport: Normative Profiles and Applications for Collegiate Athletes

ABSTRACT

Jagim, AR, Harty, PS, Jones, MT, Fields, JB, Magee, M, Smith-Ryan, AE, Luedke, J, and Kerksick, CM. Fat-free mass index in sport: normative profiles and applications for collegiate athletes. J Strength Cond Res 38(9): 1687-1693, 2024-Recent concerns have been raised regarding the ethical considerations of conducting body composition assessments in sports. Specific apprehensions pertain to the inappropriate use of percent body fat and the limited application of the results to performance and recovery. Fat-free mass index (FFMI), a height-adjusted assessment of FFM, can serve as an alternative body composition metric to focus on in sports. Fat-free mass index provides valuable context regarding an optimal amount of FFM, accounting for skeletal frame and height while helping to qualify an athlete's FFM as low, moderate, or high. This review posits that shifting the focus of body composition measures to FFM can support more ideal targets across athletic seasons, careers, and the return to play after injury. In addition, a FFM focus may help change the perception of body composition assessment and how athletes perceive their current body because of the increased focus on the FFM compartment and the goal of maximizing tissue accrual, rather than focusing on fat loss. Fat-free mass index is calculated by dividing FFM (kg) by height (m 2 ) and can serve to normalize FFM, relative to height, and enable comparisons across athletes, sport types, and sex. Previous research has identified differences in FFMI across sex and among sport categories. Still, there is a need for more published data to develop optimal ranges for FFMI across sex, sports, and positions. As more data become available, FFMI has the potential to provide normative guidelines for optimal FFM development, performance, and injury risk reduction. The purpose of the current review was to summarize FFMI values across collegiate sport categories and competitive status to provide normative profiles, according to sex and sport type.

Agreement Between the 2- and 3-Step Methods for Identifying Subtle Menstrual Disturbances

Recent methodological recommendations suggest the use of the "3-step method," consisting of calendar-based counting, urinary ovulation testing, and serum blood sampling, for the identification of subtle menstrual disturbances (SMDs). However, the use of the 3-step method is not always feasible, so a less demanding combination of calendar-based counting and urinary ovulation testing, that is, the 2-step method, may be a viable alternative.

PURPOSE

To investigate the agreement between the 2- and 3-step methods for the detection of SMDs.

METHODS

Menstrual cycles (MCs, 98) of 59 athletes were assessed using the 2- and 3-step methods. Regular-length MCs (ie, ≥21 and ≤35 d) were classified as either having no SMD (luteal phase length ≥10 d, midluteal progesterone concentration ≥16 nmol·L-1, and being ovulatory) or having an SMD (eg, short luteal phase [<10 d], inadequate luteal phase [midluteal progesterone concentration <16 nmol·L-1], or being anovulatory). Method agreement was assessed using the McNemar test and Cohen kappa (κ).

RESULTS

Substantial agreement was observed between methods (κ = .72; 95% CI, .53-.91), but the 2-step method did not detect all MCs with an SMD, resulting in evidence of systematic bias (χ2 = 5.14; P = .023). The 2-step method detected 61.1% of MCs that had an SMD ([51.4, 70.8]), as verified using the 3-step method, and correctly identified 100% of MCs without an SMD.

CONCLUSIONS

MCs classified as being disturbed using the 2-step method could be considered valid evidence of SMDs. However, MCs classified without SMDs do not definitively confirm their absence, due to the proven underdetection via the 2-step method.

Exploring the relationship between low energy availability, depression and eating disorders in female athletes: a cross-sectional study

Objective

This cross-sectional study aimed to investigate the role of low energy availability (LEA) in the interplay between depression and disordered eating/eating disorders (DE/EDs) among female athletes. The International Olympic Committee consensus statement on Relative Energy Deficiency in Sport (REDs) identified depression as both an outcome of LEA and a secondary risk factor for REDs. However, the direct link between LEA and depression has yet to be fully established.

Methods

We assessed 57 female athletes participating in weight-sensitive sports at different levels of competition training at least four times a week. Assessment was conducted using laboratory analyses, clinical interviews and the Patient Health Questionnaire-9 questionnaire. Participants were recruited through various channels, including German sports clubs, Olympic training centres, social media platforms and the distribution of flyers at competitions. Indicators of LEA were defined if at least two of the following three physiological indicators were present: menstrual disturbances, suppressed resting metabolic rate and suppressed thyroid hormones. Logistic and linear regression analysis were used to examine the relationship between LEA, depression and DE/ED.

Results

The lifetime prevalence of depressive disorders was 29.6%. 19% of the participants were diagnosed with an ED, and an additional 22.6% exhibited DE.LEA was not significantly associated with either lifetime prevalence of depressive disorders or current depressive symptoms. However, a significant association was found between depression and DE/ED in terms of both lifetime prevalence and current depressive symptoms. DE/ED increased the probability of lifetime prevalence of depressive disorders by 34% (19%-49%) compared with normal eating behaviour.

Conclusion

We found no evidence that LEA is an independent factor for depression in female athletes. Its association with LEA and REDs appears to occur primarily in the presence of DE/ED.

Training with reduced carbohydrate availability affects markers of bone resorption and formation in male academy soccer players from the English Premier League

PURPOSE

To test the hypothesis that training with reduced carbohydrate (CHO) availability increases bone resorption in adolescent soccer players.

METHODS

In a randomised crossover design, ten male players (age: 17.4 ± 0.8 years) from an English Premier League academy completed an acute 90-min field-based training session (occurring between 10:30-12:00) in conditions of high (TRAIN HIGH; 1.5 g.kg-1, 60 g, 1.5 g.kg-1 and 1.5 g.kg-1 consumed at 08:00, during training, 12:30 and 13:30, respectively) or low CHO availability (TRAIN LOW; 0 g.kg-1). Participants also completed a non-exercise trial (REST) under identical dietary conditions to TRAIN LOW. Venous blood samples were obtained at 08:30, 10:30, 12:30 and 14:30 for assessment of bone resorption (βCTX), bone formation (PINP) and calcium metabolism (PTH and ACa).

RESULTS

External training load did not differ (all P > 0.05) between TRAIN HIGH and TRAIN LOW, as evident for total distance (5.6 ± 0.8; 5.5 ± 0.1 km), average speed (81 ± 9; 85 ± 12 m.min-1) and high-speed running (350 ± 239; 270 ± 89 m). Area under the curve for both βCTX and PINP was significantly greater (P < 0.01 and P = 0.03) in TRAIN LOW versus TRAIN HIGH, whilst no differences in PTH or ACa (P = 0.11 and P = 0.89) were observed between all three trials.

CONCLUSION

CHO restriction before, during and after an acute soccer training session increased bone (re)modelling markers in academy players. Despite acute anabolic effects of bone formation, the long-term consequence of bone resorption may impair skeletal development and increase injury risk during growth and maturation.

Energy expenditure, intake and availability in female soccer players via doubly labelled water: Are we misrepresenting low energy availability?

Female soccer players have been identified as presenting with low energy availability (LEA), though the prevalence of LEA may be overestimated given inaccuracies associated with self-reporting dietary intakes. Accordingly, we aimed to quantify total daily energy expenditure (TDEE) via the doubly labelled water (DLW) method, energy intake (EI) and energy availability (EA). Adolescent female soccer players (n = 45; 16 ± 1 years) completed a 9-10 day 'training camp' representing their national team. Absolute and relative TDEE was 2683 ± 324 and 60 ± 7 kcal kg-1 fat free mass (FFM), respectively. Mean daily EI was lower (P < 0.01) when players self-reported using the remote food photography method (RFPM) (2047 ± 383 kcal day-1) over a 3-day period versus DLW derived EI estimates accounting for body mass (BM) changes (2545 ± 518 kcal day-1) over 7-8 days, representing a mean daily Δ of 499 ± 526 kcal day-1 and 22% error when using the RFPM. Estimated EA was different (P < 0.01) between methods (DLW: 48 ± 14 kcal kg-1 FFM, range: 22-82; RFPM: 37 ± 8 kcal kg-1 FFM, range: 22-54), such that prevalence of LEA (<30 kcal kg-1 FFM) was lower in DLW compared with RFPM (5% vs. 15%, respectively). Data demonstrate the potential to significantly underestimate EI when using self-report methods. This approach can therefore cause a misrepresentation and an over-prevalence of LEA, which is the underlying aetiology of 'relative energy deficiency in sport' (REDs). HIGHLIGHTS: What is the central question of this study? Do self-reported dietary intakes (via remote food photography method, RFPM) overestimate low energy availability (LEA) prevalence in female soccer players compared with energy intake evaluation from the doubly labelled water (DLW) method? What is the main finding and its importance? Estimated energy availability is greater with the DLW method compared with RFPM, such that the prevalence of LEA is greater when self-reporting dietary intakes. Accordingly, data demonstrate the potential to misrepresent the prevalence of LEA, an underlying factor in the aetiology of 'relative energy deficiency in sport' (REDs).

Bone stress injuries in athletics (track and field) championships: findings from a prospective injury surveillance conducted across 24 international championships with 29,147 registered athletes

BACKGROUND

Athletics (track and field) athletes are prone to develop bone stress injuries (BSIs) but epidemiological data on BSIs from top-level sports events are scarce.

OBJECTIVE

To describe the incidence and characteristics of BSIs during 24 international athletics championships held from 2007 to 2023.

METHODS

BSI-related data were prospectively collected during 24 international athletics championships, including the Olympic Games (n = 3), World Outdoor Championships (n = 4), European Outdoor Championships (n = 6), World Indoor Championships (n = 3) and European Indoor Championships (n = 8). Descriptive and comparative statistics were used to assess the epidemiological characteristics of BSIs.

RESULTS

BSIs accounted for 1.5% of all reported injuries (n = 36; 1.2 per 1000 registered athletes (95%CI 0.8 to 1.6)). No significant difference of BSI incidence was detected between female (2.0 per 1000 athletes (95%CI: 0.9 to 2.3)) and male athletes (0.9 per 1000 athletes (95%CI: 0.4 to 1.4)) (relative risk (RR) = 1.73, 95%CI: 0.88 to 3.40). BSI incidence was significantly higher during outdoor championships (1.6 per 1000 registered athletes (95%CI: 1.0 to 2.1)) as compared to indoor championships (0.2 per 1000 registered athletes (95%CI: 0.0 to 0.5)) (RR = 10.4, 95%CI: 1.43 to 76.0). Most BSIs were sustained in the foot (n = 50%) or leg (n = 33%). BSIs were reported in athletes participating in endurance disciplines (52.8%) or in explosive disciplines (47.2%).

CONCLUSIONS

BSIs represent a small portion of injuries sustained during international athletics championships. Collective results suggest that injury rates are higher in outdoor competitions as compared to indoor competitions. The most common injury locations comprise the foot and leg.

CLINICAL TRIAL NUMBER

Not applicable.

Differences in bone mineral density and associated factors in dancers and other female athletes

Dancers are susceptible to relative energy deficiency in sport (RED-S), specifically low bone mineral density (BMD). Little is known about how dancers' BMD compares to other athletic populations. The objective of this study was to examine the association between participant characteristics and total body areal BMD (aBMD) among female pre-professional dancers compared to other female athletes. Two hundred sixty-nine females (132 pre-professional dancers (17.6 (3.2) years) and 137 sport participants (22.8 (2.6) years) were included in this study. aBMD (g/cm2) was estimated using dual X-ray absorptiometry. Multivariable linear regression was used to examine the association between height-adjusted z-scores of total body aBMD (aBMD-Z) and age (years), body mass index (BMI) (z-score), supplement intake, history of stress fracture, irregular menses, MRI/bone scan, 1-year injury history, oral contraceptives, and activity (dance/sport). Total body aBMD and aBMD-Z were lower in dancers than athletes (dancers: aBMD = 1.03 g/cm2 (95% CI: 1.01, 1.05); aBMD-Z = -0.28 (-0.43, -0.12) (p < 0.001); athletes: aBMD = 1.14 g/cm2 (95% CI: 1.12, 1.16); aBMD-Z = 0.41 (0.25, 0.57) (p < 0.001)). aBMD-Z increased with age (β = 0.054, 95% CI: 0.017, 0.092; p = 0.004) and BMI (β = 0.221, 95% CI: 0.006, 0.415; p = 0.043). Activity type modified the relationship between BMI and aBMD-Z (β = 0.323, 95% CI: 0.025, 0.621; p < 0.033) with a stronger positive association in dancers, compared to other female athletes. Dancers had lower total body aBMD and aBMD-Z than other female athletes. aBMD-Z increases with age in female pre-professional dancers and other female athletes. A stronger association exists between aBMD-Z and BMI in dancers than athletes. Future studies should consider changes in aBMD-Z during adolescence and associations with increased risk of bone injury.

Risk of low energy availability, eating disorders and food insecurity amongst development female rugby league players

BACKGROUND

There have been several published studies on the prevalence of low energy availability (LEA) risk amongst North American and European endurance athletes. Yet the prevalence and risk factors amongst rugby league players are less well understood. This study assessed the prevalence of low energy availability risk, eating disorder risk, and food security amongst players from a female National Rugby League squad in Australia.

METHODS

Players from one Australian professional rugby league club volunteered to participate in the study. An online questionnaire was conducted to determine the prevalence of low energy availability (Low Energy Availability in Females Questionnaire [LEAF-Q]), eating disorder risk (Eating Disorders Inventory [EDI-3]), and food security.

RESULTS

Differences between those "at risk" and "not at risk" based on their total LEAF-Q score were determined. Of the 28 players, 64% (N.=18) were at risk of LEA. Raw scores for the EDI-3 subscales, body dissatisfaction (P=0.043), bulimia (P=0.002), composite score (P=0.038), were significantly higher for those at risk and not at risk of LEA. Forty percent of players had some level of food insecurity.

CONCLUSIONS

The results suggest LEA risk is similar to other populations and those at risk of LEA are more likely to have an elevated clinical risk of eating disorders. Food security is also an issue in this population and could contribute to LEA risk for some. Future research is needed amongst team sports athletes to understand interplay between eating disorder risk and food insecurity with LEA risk.

Energy Expenditure in Humans: Principles, Methods, and Changes Throughout the Life Course

Humans require energy to sustain their daily activities throughout their lives. This narrative review aims to (a) summarize principles and methods for studying human energy expenditure, (b) discuss the main determinants of energy expenditure, and (c) discuss the changes in energy expenditure throughout the human life course. Total daily energy expenditure is mainly composed of resting energy expenditure, physical activity energy expenditure, and the thermic effect of food. Total daily energy expenditure and its components are estimated using variations of the indirect calorimetry method. The relative contributions of organs and tissues determine the energy expenditure under different physiological conditions. Evidence shows that energy expenditure varies along the human life course, at least in part due to changes in body composition, the mass and specific metabolic rates of organs and tissues, and levels of physical activity. This information is crucial to estimate human energy requirements for maintaining health throughout the life course.