The reported prevalence of low energy availability (LEA) in female and male track and field athletes is between 18% and 58% with the highest prevalence among athletes in endurance and jump events. In male athletes, LEA may result in reduced testosterone levels and libido along with impaired training capacity. In female track and field athletes, functional hypothalamic amenorrhea as consequence of LEA has been reported among 60% of elite middle- and long-distance athletes and 23% among elite sprinters. Health concerns with functional hypothalamic amenorrhea include impaired bone health, elevated risk for bone stress injury, and cardiovascular disease. Furthermore, LEA negatively affects recovery, muscle mass, neuromuscular function, and increases the risk of injuries and illness that may affect performance negatively. LEA in track and field athletes may occur due to intentional alterations in body mass or body composition, appetite changes, time constraints, or disordered eating behavior. Long-term LEA causes metabolic and physiological adaptations to prevent further weight loss, and athletes may therefore be weight stable yet have impaired physiological function secondary to LEA. Achieving or maintaining a lower body mass or fat levels through long-term LEA may therefore result in impaired health and performance as proposed in the Relative Energy Deficiency in Sport model. Preventive educational programs and screening to identify athletes with LEA are important for early intervention to prevent long-term secondary health consequences. Treatment for athletes is primarily to increase energy availability and often requires a team approach including a sport physician, sports dietitian, physiologist, and psychologist.
Anna K. Melin, Ida A. Heikura, Adam Tenforde and Margo Mountjoy
Lindy M. Castell, David C. Nieman, Stéphane Bermon and Peter Peeling
The main focus of this review is illness among elite athletes, how and why it occurs, and whether any measures can be taken to combat it or to prevent its onset. In particular, there is particular interest in exercise-induced immunodepression, which is a result of the immune system regarding exercise (e.g., prolonged, exhaustive exercise) as a challenge to its function. This promotes the inflammatory response. There is often a high incidence of illness in athletes after undertaking strenuous exercise, particularly among those competing in endurance events, not only mainly in terms of upper respiratory tract illness, but also involving gastrointestinal problems. It may well be that this high incidence is largely due to insufficient recovery time being allowed after, for example, a marathon, a triathlon, or other endurance events. Two examples of the incidence of upper respiratory tract illness in moderate versus endurance exercise are provided. In recent years, increasing numbers of research studies have investigated the origins, symptoms, and incidence of these bouts of illness and have attempted to alleviate the symptoms with supplements, sports foods, or immunonutrition. One aspect of the present review discusses iron deficiency, which has been primarily suggested to have an impact upon cell-mediated immunity. Immunonutrition is also discussed, as are new techniques for investigating links between metabolism and immune function.
Douglas J. Casa, Samuel N. Cheuvront, Stuart D. Galloway and Susan M. Shirreffs
The 2019 International Amateur Athletics Federation Track-and-Field World Championships will take place in Qatar in the Middle East. The 2020 Summer Olympics will take place in Tokyo, Japan. It is quite likely that these events may set the record for hottest competitions in the recorded history of both the Track-and-Field World Championships and Olympic Games. Given the extreme heat in which track-and-field athletes will need to train and compete for these games, the importance of hydration is amplified more than in previous years. The diverse nature of track-and-field events, training programs, and individuality of athletes taking part inevitably means that fluid needs will be highly variable. Track-and-field events can be classified as low, moderate, or high risk for dehydration based on typical training and competition scenarios, fluid availability, and anticipated sweat losses. This paper reviews the risks of dehydration and potential consequences to performance in track-and-field events. The authors also discuss strategies for mitigating the risk of dehydration.
Trent Stellingwerff, James P. Morton and Louise M. Burke
Over the last decade, in support of training periodization, there has been an emergence around the concept of nutritional periodization. Within athletics (track and field), the science and art of periodization is a cornerstone concept with recent commentaries emphasizing the underappreciated complexity associated with predictable performance on demand. Nevertheless, with varying levels of evidence, sport and event specific sequencing of various training units and sessions (long [macrocycle; months], medium [mesocycle; weeks], and short [microcycle; days and within-day duration]) is a routine approach to training periodization. Indeed, implementation of strategic temporal nutrition interventions (macro, meso, and micro) can support and enhance training prescription and adaptation, as well as acute event specific performance. However, a general framework on how, why, and when nutritional periodization could be implemented has not yet been established. It is beyond the scope of this review to highlight every potential nutritional periodization application. Instead, this review will focus on a generalized framework, with specific examples of macro-, meso-, and microperiodization for the macronutrients of carbohydrates, and, by extension, fat. More specifically, the authors establish the evidence and rationale for situations of acute high carbohydrate availability, as well as the evidence for more chronic manipulation of carbohydrates coupled with training. The topic of periodized nutrition has made considerable gains over the last decade but is ripe for further scientific progress and field application.
Jennifer Sygo, Alicia Kendig Glass, Sophie C. Killer and Trent Stellingwerff
Athletes participating in the athletics (track and field) events of jumps, throws, and combined events (CEs; seven-event heptathlon and 10-event decathlon) engage in training and competition that emphasize speed and explosive movements, requiring optimal power–weight ratios. While these athletes represent a wide range of somatotypes, they share an emphasis on Type IIa and IIx muscle fiber typing. In general, athletes competing in jumps tend to have a lower body mass and may benefit from a higher protein (1.5–1.8 g PRO·kg−1·day−1) and lower carbohydrate (3–6 g CHO·kg−1·day−1) diet. Throwers tend to have a higher body mass, but with considerable differences between events. Their intense, whole-body training program suggests higher PRO requirements (1.5–2.2 g PRO·kg−1·day−1), while CHO needs (per kg) are similar to jumpers. The CE athletes must strike a balance between strength and muscle mass for throws and sprints, while maintaining a low enough body mass to maximize performance in jumps and middle-distance events. CE athletes may benefit from a higher PRO (1.5–2 g PRO·kg−1·day−1) and moderate CHO (5–8 g CHO·kg−1·day−1) diet with good energy availability to support multiple daily training sessions. Since they compete over 2 days, well-rehearsed competition-day fueling and recovery strategies are imperative for CE athletes. Depending on their events’ bioenergetic demands, athletes in throws, jumps, and CE may benefit from the periodized use of ergogenic aids, including creatine, caffeine, and/or beta-alanine. The diverse training demands, physiques, and competitive environments of jumpers, throwers, and CE athletes necessitate nutrition interventions that are periodized throughout the season and tailored to the individual needs of the athlete.
Louise M. Burke, Linda M. Castell, Douglas J. Casa, Graeme L. Close, Ricardo J. S. Costa, Ben Desbrow, Shona L. Halson, Dana M. Lis, Anna K. Melin, Peter Peeling, Philo U. Saunders, Gary J. Slater, Jennifer Sygo, Oliver C. Witard, Stéphane Bermon and Trent Stellingwerff
The International Association of Athletics Federations recognizes the importance of nutritional practices in optimizing an Athlete’s well-being and performance. Although Athletics encompasses a diverse range of track-and-field events with different performance determinants, there are common goals around nutritional support for adaptation to training, optimal performance for key events, and reducing the risk of injury and illness. Periodized guidelines can be provided for the appropriate type, amount, and timing of intake of food and fluids to promote optimal health and performance across different scenarios of training and competition. Some Athletes are at risk of relative energy deficiency in sport arising from a mismatch between energy intake and exercise energy expenditure. Competition nutrition strategies may involve pre-event, within-event, and between-event eating to address requirements for carbohydrate and fluid replacement. Although a “food first” policy should underpin an Athlete’s nutrition plan, there may be occasions for the judicious use of medical supplements to address nutrient deficiencies or sports foods that help the athlete to meet nutritional goals when it is impractical to eat food. Evidence-based supplements include caffeine, bicarbonate, beta-alanine, nitrate, and creatine; however, their value is specific to the characteristics of the event. Special considerations are needed for travel, challenging environments (e.g., heat and altitude); special populations (e.g., females, young and masters athletes); and restricted dietary choice (e.g., vegetarian). Ideally, each Athlete should develop a personalized, periodized, and practical nutrition plan via collaboration with their coach and accredited sports nutrition experts, to optimize their performance.
Ben Desbrow, Nicholas A. Burd, Mark Tarnopolsky, Daniel R. Moore and Kirsty J. Elliott-Sale
Adolescent, female, and masters athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the specific demands of age- and gender-related physiological changes. Dietary education and recommendations for these special population athletes require a focus on eating for long-term health, with special consideration given to “at-risk” dietary patterns and nutrients (e.g., sustained restricted eating, low calcium, vitamin D and/or iron intakes relative to requirements). Recent research highlighting strategies to address age-related changes in protein metabolism and the development of tools to assist in the management of Relative Energy Deficiency in Sport are of particular relevance to special population athletes. Whenever possible, special population athletes should be encouraged to meet their nutrient needs by the consumption of whole foods rather than supplements. The recommendation of dietary supplements (particularly to young athletes) overemphasizes their ability to manipulate performance in comparison with other training/dietary strategies.
Graeme L. Close, Craig Sale, Keith Baar and Stephane Bermon
Injuries are an inevitable consequence of athletic performance with most athletes sustaining one or more during their athletic careers. As many as one in 12 athletes incur an injury during international competitions, many of which result in time lost from training and competition. Injuries to skeletal muscle account for over 40% of all injuries, with the lower leg being the predominant site of injury. Other common injuries include fractures, especially stress fractures in athletes with low energy availability, and injuries to tendons and ligaments, especially those involved in high-impact sports, such as jumping. Given the high prevalence of injury, it is not surprising that there has been a great deal of interest in factors that may reduce the risk of injury, or decrease the recovery time if an injury should occur: One of the main variables explored is nutrition. This review investigates the evidence around various nutrition strategies, including macro- and micronutrients, as well as total energy intake, to reduce the risk of injury and improve recovery time, focusing upon injuries to skeletal muscle, bone, tendons, and ligaments.
Shona L. Halson, Louise M. Burke and Jeni Pearce
Domestic and international travel represents a regular challenge to high-performance track-and-field athletes, particularly when associated with the pressure of competition or the need to support specialized training (e.g., altitude or heat adaptation). Jet lag is a challenge for transmeridian travelers, while fatigue and alterations to gastrointestinal comfort are associated with many types of long-haul travel. Planning food and fluid intake that is appropriate to the travel itinerary may help to reduce problems. Resynchronization of the body clock is achieved principally through manipulation of zeitgebers, such as light exposure; more investigation of the effects of melatonin, caffeine, and the timing/composition of meals will allow clearer guidelines for their contribution to be prepared. At the destination, the athlete, the team management, and catering providers each play a role in achieving eating practices that support optimal performance and success in achieving the goals of the trip. Although the athlete is ultimately responsible for his or her nutrition plan, best practice by all parties will include pretrip consideration of risks around the quality, quantity, availability, and hygiene standards of the local food supply and the organization of strategies to deal with general travel nutrition challenges as well as issues that are specific to the area or the special needs of the group. Management of buffet-style eating, destination-appropriate protocols around food/water and personal hygiene, and arrangement of special food needs including access to appropriate nutritional support between the traditional “3 meals a day” schedule should be part of the checklist.
Ricardo J.S. Costa, Beat Knechtle, Mark Tarnopolsky and Martin D. Hoffman
Ultramarathon running events and participation numbers have increased progressively over the past three decades. Besides the exertion of prolonged running with or without a loaded pack, such events are often associated with challenging topography, environmental conditions, acute transient lifestyle discomforts, and/or event-related health complications. These factors create a scenario for greater nutritional needs, while predisposing ultramarathon runners to multiple nutritional intake barriers. The current review aims to explore the physiological and nutritional demands of ultramarathon running and provide general guidance on nutritional requirements for ultramarathon training and competition, including aspects of race nutrition logistics. Research outcomes suggest that daily dietary carbohydrates (up to 12 g·kg−1·day−1) and multiple-transportable carbohydrate intake (∼90 g·hr−1 for running distances ≥3 hr) during exercise support endurance training adaptations and enhance real-time endurance performance. Whether these intake rates are tolerable during ultramarathon competition is questionable from a practical and gastrointestinal perspective. Dietary protocols, such as glycogen manipulation or low-carbohydrate high-fat diets, are currently popular among ultramarathon runners. Despite the latter dietary manipulation showing increased total fat oxidation rates during submaximal exercise, the role in enhancing ultramarathon running performance is currently not supported. Ultramarathon runners may develop varying degrees of both hypohydration and hyperhydration (with accompanying exercise-associated hyponatremia), dependent on event duration, and environmental conditions. To avoid these two extremes, euhydration can generally be maintained through “drinking to thirst.” A well practiced and individualized nutrition strategy is required to optimize training and competition performance in ultramarathon running events, whether they are single stage or multistage.