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Children-competiton-damsgaard


FIS Medical Committee Educational Series
Dr. Rasmus Damsgaard
Member of the FIS Medical Committee
Children in competitive sports
Clinical implications
Introduction

Concern has been raised regarding the linear growth and pubertal development in children
participating in gymnastics and ballet (1,2). Accordingly, it has been suggested that female
gymnasts should decrease their training during puberty (3). In contrast, female swimmers, track
athletes, rowers and volleyball players seem to grow and develop normally (2,4,5). Less is
known about boys participating in competitive sports; however, the available data suggest that
growth and puberty are little (6) or not affected by training (7,8).
The explanation for the restricted growth and delayed puberty in some sports and not in others is
unclear. A possible adverse effect of intensive training on growth and puberty has been
suggested (2,3), since catch-up growth has been observed and the normal menstrual pattern
restored when training was markedly reduced. On the other hand, two studies have shown that
differences in stature between children in different sports existed before the onset of training,
indicating that constitutional factors may play a role in the selection of competitive athletes (4,9).
It is a common belief that gymnasts have disproportional body segments with relatively shorter
legs, suggesting that repetitive compression of the epiphyses might inhibit growth of the long
bones in gymnasts. However, most studies on body proportions have not found any differences
between children from various sports (7,10).
Athletes in aesthetic sports such as gymnastics, figure skating and ballet dancers have been
found to be leaner than athletes in other sports (1,11,12,13,14). A light body weight obviously
enables these athletes and dancers to perform more acrobatic rotations and jumps than their
heavier counterparts. A study of the body mass index (BMI) in children in competitive sports
showed that BMI was reduced in female gymnasts long before the onset of training, indicating a
selection of lean children into gymnastics (9). However, it has been suggested that gymnasts
and ballet dancers have an exaggerated focus on nutrition, causing a negative energy balance
in order to optimize their body composition (15)
Hormones known to be involved in normal growth and puberty may mediate the possible
adverse effects of intensive training. Decreased levels of Insulin-like Growth Factor I (IGF-I)
have been shown after short periods of exercise in adolescence (16,17). Low levels of estrogen
excretion have been found in adolescent rowers with irregular menstrual patterns (18). This
finding is somewhat in accordance with the lower levels of plasma estradiol found in some highly
trained women athletes (19). However, it has not been established whether long-term intensive
training in pubertal children is associated with decreased levels of hormonal factors.
Bone mineralization is dependent on sex hormones and female athletes with delayed age at
menarche have been thought to be at risk of osteoporosis later in adult life (20). In contrast, the
positive effect of mechanical stress on bones during childhood as a determinant of adult peak
bone mass has received increasing attention during the past decade (21,22). This hypothesis
has been confirmed in a study of pubertal female gymnasts who increased their whole body
mineral content significantly after one year of training (23).
However, a negative energy intake has been related to decreased levels of hormonal factors, a
delay in age at menarche and irregularities of the menstrual cycle (24,25) and thereby may
compromise normal bone mineral accretion (18,26).
Clinical implications

Only very few competitive adolescent athletes attain the amount of training hours needed for
success at major international competitions. However, the suggested impaired growth and
pubertal development in some female athletes and ballet dancers emphasizes the need for
guidelines concerning training intensities. This is especially important for athletes in aesthetic
sports where regular training is started before onset of puberty and a low body weight is an
advantage.
Considering that only little or no adverse effects of training on growth and pubertal development
have been observed in children in sports corrected for constitutional factors, a suggested limit of
15 hours of training per week (27) seems reasonable beyond which prepubertal and pubertal
athletes at risk should be examined regularly (every six to 12 months). The examination should
include anthropometrical measurements, assessment of pubertal status, recording of injuries,
statements of nutritional habits and information on parental heights and their pubertal
development including the mother’s age at menarche. If a decrease in linear growth is observed
in combination with a late pubertal development, bone age, hormonal growth factors and sex
hormones in the blood should be determined. These further investigations will help to determine
whether the affected growth is due to constitutional factors, high training intensities, or in very
rare cases disease. If constitutional delay and disease can be excluded, training intensities
should be reduced considerably as a decrease in training intensity has been found to improve
the tempo of linear growth and pubertal development (2). In order to estimate whether final
height is compromised and pubertal development delayed, it is advised to follow the athletes
until termination of puberty or at least until peak height velocity and, in girls, age at menarche is
reached.
Perhaps training in tall-stature sports such as swimming and team handball should be designed
according to the pubertal development of the single athlete as the timing and tempo of puberty
varies significantly among adolescents. Thus, a balanced energy input and expenditure in
aesthetic sports such as gymnastics may be more important for normal growth than a reduction
of training intensity.
Rasmus Damsgaard, MD, PhD, February 2001
contact e-mail: rdamsgaard@mail.dk
References

1 Pigeon P, Oliver I, Charlet JP, Rochiccioli P. Intensive dance practice. Repercussions on growth and puberty. Am J Sports Med. 1997:25:243-247. 2 Theintz GE, Howald H, Weiss U, Sizonenko PC. Evidence for a reduction of growth potential in adolescent female gymnasts. J Pediatr. 1993:122:306-313. 3 Mansfield MJ, Emans SJ. Growth in female gymnasts: should training decrease during puberty? J Pediatr. 1993:122:237-240. 4 Peltenburg AL, Erich WB, Zonderland ML, Bernink MJ, VanDenBrande JL, Huisveld IA. A retrospective growth study of female gymnasts and girl swimmers. Int J Sports Med. 1984:5:262-267. 5 Malina RM. Attained size and growth rate of female volleyball players between 9 and 13 years of age. Pediatric Exercise Science. 1994:6:257-266. 6 Cacciari E, Mazzanti L, Tassinari D et al. Effects of sport (football) on growth: auxological, anthropometric and hormonal aspects. Eur J Appl Physiol. 1990:61:149-158. 7 Malina RM. Physical growth and biological maturation of young athletes. Exerc Sport Sci 8 Baxter-Jones ADG, Helms PJ. Effects of training at a young age: A review of the training of young athletes (TOYA) study. Pediatric Exercise Science. 1996:8:310-327. 9 Damsgaard R, Bencke J, Matthiesen G, Petersen JH, Müller J. Is prepubertal growth adversely affected by sport? Med Sci Sports Exerc. 2000:32:1698-1703. 10 Damsgaard R, Bencke J, Matthiesen G, Petersen JH, Müller J. Body proportions, body composition and pubertal development of children in competitive sports. Scand J Med Sci Sports. 2001:11:54-60. 11 Lindholm C, Hagenfeldt K, Ringertz BM. Pubertal development in elite juvenile gymnasts. Effects of physical training. Acta Obstet Gynecol Scand. 1994:73:269-273. 12 Baxter JA, Helms P, Maffulli N, Baines PJ, Preece M. Growth and development of male gymnasts, swimmers, soccer and tennis players: a longitudinal study. Ann Hum Biol. 1995:22:381-394. 13 Caldarone G, Leglise M, Giampietro M, Berlutti G. Anthropometric measurements, body composition, biological maturation and growth predictions in young female gymnasts of high agonistic level. J Sports Med Phys Fitness. 1986:26:263-273. 14 Caldarone G, Leglise M, Giampietro M, Berlutti G. Anthropometric measurements, body composition, biological maturation and growth predictions in young male gymnasts of high agonistic level. J Sports Med Phys Fitness. 1986:26:406-415. 15 Bale P, Goodway J. Performance variables associated with the competitive gymnast. Sports 16 Eliakim A, Brasel JA, Mohan S, Barstow TJ, Berman N, Cooper DM. Physical fitness, endurance training, and the growth hormone-insulin- like growth factor I system in adolescent females. J Clin Endocrinol Metab. 1996:81:3986-3992. 17 Eliakim A, Brasel JA, Mohan S, Wong WLT, Cooper DM. Increased physical activity and the growth hormone-IGF-I axis in adolescent males. Am J Physiol. 1998:275:R308-R314. 18 Morris FL, Payne WR, Wark JD. The impact of intense training on endogenous estrogen and progesterone concentrations and bone mineral acquisition in adolescent rowers. Osteoporos Int. 1999:10:361-368. 19 Shangold MM. Exercise and the adult female: hormonal and endocrine effects. Exerc Sport 20 De Cree C. Sex steroid metabolism and menstrual irregularities in the exercising female. A review. Sports Med. 1998:25:369-406. 21 Dyson K, Blimkie CJ, Davison KS, Webber CE, Adachi JD. Gymnastic training and bone density in pre-adolescent females. Med Sci Sports Exerc. 1997:29:443-450. 22 Nickols-Richardson SM, Modlesky CM, O'Connor PJ, Lewis RD. Premenarcheal gymnasts possess higher bone mineral density than controls. Med Sci Sports Exerc. 2000:32:63-69. 23 Damsgaard R, Molgaard C, Bencke J, Müller J. Pubertal gymnasts increase whole body mineral content in contrast to swimmers during one year of intensive training. In: European Society of Paediatric Endocrinology: Book of abstracts. Brussels;2000. 24 Frisch RE, McArthur JW. Menstrual cycles: fatness as a determinant of minimum weight for height necessary for their maintenance or onset. Science. 1974:185:949-951. 25 Frisch RE, Wyshak G, Vincent L. Delayed menarche and amenorrhea in ballet dancers. N 26 Lloyd T, Rollings N, Andon MB et al. Determinants of bone density in young women. I. Relationships among pubertal development, total body bone mass, and total body bone density in premenarchal females. J Clin Endocrinol Metab. 1992:75:383-387. 27 Theintz GE. Endocrine adaptation to intensive physical training during growth. Clin

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