The measurement of basal metabolism, the lowest amount of energy required for the body to function, is of interest to athletes due to its potential as a diagnostic tool to detect low energy availability ( Loucks et al., 2011 ; Mountjoy et al., 2015 ). The terms basal energy expenditure (BEE) and
Julia L. Bone and Louise M. Burke
Jennifer Sygo, Alicia Kendig Glass, Sophie C. Killer and Trent Stellingwerff
the training-specific requirements of developing speed and power, while also supporting good energy availability to fuel training and prevent injury and illness, occasionally, brief periods of modest energy deficit may be required to help jumpers to attain peak power-to-weight ratio for competition
Helen G. Hanstock, Andrew D. Govus, Thomas B. Stenqvist, Anna K. Melin, Øystein Sylta and Monica K. Torstveit
. Methods Study Design In a randomized design, participants were allocated to 3 groups in which each undertook a 4-week training intervention. In groups, participants completed 3 HIT sessions each week supplemented with ad libitum LIT. We measured V ˙ O 2 peak , energy availability (EA), and blood and
Amelia Carr, Kerry McGawley, Andrew Govus, Erik P. Andersson, Oliver M. Shannon, Stig Mattsson and Anna Melin
conducted in consultation with a registered dietitian. Long-Term Energy Deficiency The prevalence of conditions related to a long-term energy deficiency was assessed in the female participants using the Low Energy Availability in Females Questionnaire (LEAF-Q; Melin et al., 2014 ). Currently, there is no
Laurie Stickler, Trisha Armstrong, Alyssa Polso and Melissa Smith
Low energy availability has been identified through research as the cornerstone of the female athlete triad, yet reasons for nutritional choices among female collegiate athletes are poorly understood.
To explore the perspectives of female collegiate cross country runners on eating behaviors and attitudes toward health.
Phenomenologic qualitative study with individual, semistructured interviews.
Ten collegiate female cross country runners, ages 18–22, participated in the study. All interviews were audiotaped then transcribed. Three researchers independently coded data and developed themes and subthemes before meeting and negotiating findings.
The following four themes were identified: health behaviors, nutritional knowledge, internal and external factors, and health attitudes.
This study contributes to understanding “the why” behind health behaviors of female collegiate cross country runners. This developmental understanding may assist in interpreting the behavioral causes of low energy availability; thus, both management and prevention of the triad may be aided by this information.
Steven J. Howard, Caylee J. Cook, Rihlat Said-Mohamed, Shane A. Norris and Catherine E. Draper
An area of growth in physical activity research has involved investigating effects of physical activity on children’s executive functions. Many of these efforts seek to increase the energy expenditure of young children as a healthy and low-cost way to affect physical, health, and cognitive outcomes.
We review theory and research from neuroscience and evolutionary biology, which suggest that interventions seeking to increase the energy expenditure of young children must also consider the energetic trade-offs that occur to accommodate changing metabolic costs of brain development.
According to Life History Theory, and supported by recent evidence, the high relative energy-cost of early brain development requires that other energy-demanding functions of development (ie, physical growth, activity) be curtailed. This is important for interventions seeking to dramatically increase the energy expenditure of young children who have little excess energy available, with potentially negative cognitive consequences. Less energy-demanding physical activities, in contrast, may yield psychosocial and cognitive benefits while not overburdening an underweight child’s already scarce energy supply.
While further research is required to establish the extent to which increases in energy-demanding physical activities may compromise or displace energy available for brain development, we argue that action cannot await these findings.
David B. Pyne, Evert A. Verhagen and Margo Mountjoy
In this review, we outline key principles for prevention of injury and illness in aquatic sports, detail the epidemiology of injury and illness in aquatic athletes at major international competitions and in training, and examine the relevant scientific evidence on nutrients for reducing the risk of illness and injury. Aquatic athletes are encouraged to consume a well-planned diet with sufficient calories, macronutrients (particularly carbohydrate and protein), and micronutrients (particularly iron, zinc, and vitamins A, D, E, B6, and B12) to maintain health and performance. Ingesting carbohydrate via sports drinks, gels, or sports foods during prolonged training sessions is beneficial in maintaining energy availability. Studies of foods or supplements containing plant polyphenols and selected strains of probiotic species are promising, but further research is required. In terms of injury, intake of vitamin D, protein, and total caloric intake, in combination with treatment and resistance training, promotes recovery back to full health and training.
Jason D. Vescovi and Jaci L. VanHeest
This observational case study examined the association of inter- and intraday energy intake and exercise energy expenditure with bone health, menstrual status and hematological factors in a female triathlete. The study spanned 7 months whereby energy intake and exercise energy expenditure were monitored three times (13 d); 16 blood samples were taken, urinary hormones were assessed for 3 months, and bone mineral density was measured twice. Energy availability tended to be sustained below 30 kcal/kg FFM/d and intraday energy intake patterns were often “back-loaded” with approximately 46% of energy consumed after 6 p.m. Most triiodothyronine values were low (1.1–1.2nmol/L) and supportive of reduced energy availability. The athlete had suppressed estradiol (105.1 ± 71.7pmol/L) and progesterone (1.79 ±1.19nmol/L) concentrations as well as urinary sex-steroid metabolites during the entire monitoring period. Lumbar spine (L1-L4) bone mineral density was low (age-matched Z-score −1.4 to −1.5). Despite these health related maladies the athlete was able to perform typical weekly training loads (swim: 30–40 km, bike: 120–300 km, run 45–70 km) and was competitive as indicated by her continued improvement in ITU World Ranking during and beyond the assessment period. There is a delicate balance between health and performance that can become blurred especially for endurance athletes. Education (athletes, coaches, parents) and continued monitoring of specific indicators will enable evidence-based recommendations to be provided and help reduced the risk of health related issues while maximizing performance gains. Future research needs to longitudinally examine how performance on standardized tests in each discipline (e.g., 800-m swim, 20-km time trial, 5-km run) is impacted when aspects of the female athlete triad are present.
Dan Benardot, Wes Zimmermann, Gregory R. Cox and Saul Marks
Competitive diving involves grace, power, balance, and flexibility, which all require satisfying daily energy and nutrient needs. Divers are short, well-muscled, and lean, giving them a distinct biomechanical advantage. Although little diving-specific nutrition research on performance and health outcomes exists, there is concern that divers are excessively focused on body weight and composition, which may result in reduced dietary intake to achieve desired physique goals. This will result in low energy availability, which may have a negative impact on their power-to-weight ratio and health risks. Evidence is increasing that restrictive dietary practices leading to low energy availability also result in micronutrient deficiencies, premature fatigue, frequent injuries, and poor athletic performance. On the basis of daily training demands, estimated energy requirements for male and female divers are 3,500 kcal and 2,650 kcal, respectively. Divers should consume a diet that provides 3–8 g/kg/day of carbohydrate, with the higher values accommodating growth and development. Total daily protein intake (1.2–1.7 g/kg) should be spread evenly throughout the day in 20 to 30 g amounts and timed appropriately after training sessions. Divers should consume nutrient-dense foods and fluids and, with medical supervision, certain dietary supplements (i.e., calcium and iron) may be advisable. Although sweat loss during indoor training is relatively low, divers should follow appropriate fluid-intake strategies to accommodate anticipated sweat losses in hot and humid outdoor settings. A multidisciplinary sports medicine team should be integral to the daily training environment, and suitable foods and fluids should be made available during prolonged practices and competitions.
Gregory Shaw, Kevin T. Boyd, Louise M. Burke and Anu Koivisto
Swimming is a sport that requires considerable training commitment to reach individual performance goals. Nutrition requirements are specific to the macrocycle, microcycle, and individual session. Swimmers should ensure suitable energy availability to support training while maintaining long term health. Carbohydrate intake, both over the day and in relation to a workout, should be manipulated (3–10g/kg of body mass/day) according to the fuel demands of training and the varying importance of undertaking these sessions with high carbohydrate availability. Swimmers should aim to consume 0.3g of high-biological-value protein per kilogram of body mass immediately after key sessions and at regular intervals throughout the day to promote tissue adaptation. A mixed diet consisting of a variety of nutrient-dense food choices should be sufficient to meet the micronutrient requirements of most swimmers. Specific dietary supplements may prove beneficial to swimmers in unique situations, but should be tried only with the support of trained professionals. All swimmers, particularly adolescent and youth swimmers, are encouraged to focus on a well-planned diet to maximize training performance, which ensures sufficient energy availability especially during periods of growth and development. Swimmers are encouraged to avoid rapid weight fluctuations; rather, optimal body composition should be achieved over longer periods by modest dietary modifications that improve their food choices. During periods of reduced energy expenditure (taper, injury, off season) swimmers are encouraged to match energy intake to requirement. Swimmers undertaking demanding competition programs should ensure suitable recovery practices are used to maintain adequate glycogen stores over the entirety of the competition period.