Ultramarathon races have gained popularity with there having been an approximately four-fold increase in the number of adult finishes over the last decade (1). While representing a much smaller number, the participation in ultramarathons by children and adolescents also has increased during the past decade. Growing requests of race directors to allow race entry of underaged athletes may place them, and the medical directors they may consult, in a dilemma. While ultramarathon participation guidelines have been published relative to various medical conditions (2,3), no such guidelines have been developed on age restrictions.
One extensive database of ultramarathon performances from around the world includes more than 7700 ultramarathon finishes of children and adolescents younger than 19 yr between 1960 and 2017 (1). Across the age range, approximately 420 finishes have been recorded from participants younger than 12 yr, approximately 630 from 12- to 13-yr-olds, and another 1070 from 14- to 15-yr-olds, while the majority of ultramarathon finishes by underaged runners have been from ages 16 yr (1060), 17 yr (1570), and 18 yr (2990). Distances recorded range from 50 km to 100 miles and more, as well as multiday events. The database shows runners as young as 12 yr of age having finished 100-km ultramarathons (1).
Some sports have enacted minimum age requirements. For instance, the International Association of Athletics Federation (IAAF) required athletes to be at least 20 yr of age to participate in the 2017 marathon’s world championships in London (4). Many other marathons and popular road races have minimum age requirements of 16 to 18 yr and often require a signed waiver or guardian permission. Interestingly, the youngest athlete to participate in the 2016 Olympic Games in Rio de Janeiro was just 13 yr of age.
The United Nations General Assembly convention on the rights of the child defines children as being below the age of 18 yr, and the World Health Organization (WHO) classifies adolescents as those between the ages of 10 and 19 yr. The WHO advises that it is the responsibility of adults to assure that children grow up in a safe and nonhazardous environment and have time to learn, develop, and play.
Girls physiologically develop approximately 2 yr before boys, with puberty setting in around 12 yr of age for girls and 14 yr for boys. During this period, peak growth takes place and important hormonal and psychological changes can be observed. Other key developments through childhood and adolescence relate to the pulmonary system with increases in lung volume, ventilatory capacity and maximal oxygen uptake, the cardiovascular system with increasing stroke volume and decreasing resting heart rate, the musculoskeletal system with increases in muscle bulk and strength, and the brain with enhancement of cognitive function, all of importance for safe participation in ultramarathon running.
One of the main concerns from youth participation in ultramarathon running relates to the musculoskeletal system, as young athletes are skeletally immature and at particular risk for injuries at the growth plates, tendon attachments, and articular cartilage at the joint surfaces, especially during peak growth when injuries tend to be more common. The variable rate of growth has an influence on biomechanics, which may further predispose to injury (5). High training volumes in adult ultramarathon runners can lead to overuse injuries and stress fractures (6). The influence of repetitive stress of the magnitudes associated with ultramarathon running on an immature musculoskeletal system has not been investigated. There may be increased concern for young female athletes where the possibility of the female athlete triad also exists.
There also are potential psychological and social implications to youth from ultramarathon running. Training for ultramarathons requires considerable time, and this may impact the psychological well-being of a young person and negatively impact schooling performance and emotional and social development.
Another concern is that ultramarathons often take place in challenging and remote environments, and runners may experience unexpected medical problems (e.g., exercise-associated hyponatremia, gastrointestinal distress, heat stress, etc.) and other significant challenges like being lost in the wilderness. Young athletes are less equipped to handle heat stress, and their decision-making and problem-solving capacities are not yet fully developed. Such environmental risks must be considered in decisions about participatory age requirements for ultramarathons.
Legal implications and the minimum age an individual can legally consent also need to be considered. This may vary across countries. Also from the perspective of a race director, it is important to have liability insurance and this may not include underaged athletes or may come at the cost of a high premium.
Unfortunately, scientific evidence to support decisions about minimum age requirements for ultramarathon participation is nonexistent. One study examining 310 marathon finishers at the Twin Cities Marathon between the ages of 7 and 17 yr recorded only minor medical problems, leading the authors to conclude that as long as the psychological and physiological development of the child was not disrupted, participation could be permitted (7). However the long-term effects have not been examined from participation in marathons, let alone participation in ultramarathons.
In other endurance sports, such as triathlons, it has been proposed by the American Academy of Pediatrics that it is reasonably safe for children and adolescents to participate as long as the events are modified to be age appropriate. These events should be of shorter duration and distance and be held in safe environmental conditions. The American Academy of Pediatrics Council on Sports Medicine and Fitness generally recommends limiting sporting activities to a maximum of 5 d·wk−1 with at least one day off from any organized physical activity plus abstinence for at least 2 to 3 months·yr−1 in that particular sport so the body can recover and refresh, reducing the risk of burnout or overtraining syndrome (8).
Given the lack of scientific evidence to support recommendations about minimum age requirements for ultramarathon participation, we suggest there is a need for research on this topic, and in the meantime, an expert panel should develop age guidelines for use by ultramarathon race and medical directors. The panel should be capable of making reasonable judgments on the physiological and psychological impact to youth from participating in ultramarathons. Until then, a cautious and common sense approach is warranted.
2. Hoffman MD, Pasternak A, Rogers IR, et al. Medical services at ultra-endurance foot races in remote environments: medical issues and consensus guidelines. Sports Med.
3. Joslin J, Hoffman MD, Rogers I, et al. Special considerations in medical screening for participants in remote endurance events. Sports Med.
5. Krabak BJ, Snitily B, Milani CJ. Running injuries during adolescence and childhood. Phys. Med. Rehabil. Clin. N. Am.
6. Hoffman MD, Krishnan E. Health and exercise-related medical issues among 1,212 ultramarathon runners: baseline findings from the Ultrarunners Longitudinal TRAcking (ULTRA) Study. PloS One.
7. Roberts WO. Can children and adolescents run marathons? Sports Med.
8. Brenner JS, American Academy of Pediatrics Council on Sports Medicine and Fitness. Overuse injuries, overtraining, and burnout in child and adolescent athletes. Pediatrics
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