Selected body composition and growth measures of junior elite gymnasts

Carbohydrate use and reduction in number of balance beam falls: implications for mental and physical fatigue

BACKGROUND

Artistic Gymnastics is a sport where athletes are frequently fatigued. One element that might influence this aspect is carbohydrate, an important energy substrate for the muscles and the CNS. Our goal was to investigate the influence of fatigue over artistic gymnastics athlete's performance and the effects of a carbohydrate supplementation on their performance.

METHODS

We evaluated 15 athletes divided in 2 groups (control and fatigue) from 12 to 14 years old in two different experimental days. On the first day (water day), they did 5 sets of exercises on the balance beam (experimental protocol) ingesting only water, CG (control group) warmed up before the experimental protocol and FG (fatigue group) did a fatigue circuit, warm up exercises and then the experimental protocol. On the second day (carbohydrate day), we used the same protocol but CG ingested a sugar free flavored juice and FG ingested a 20% concentration maltodextrin solution before the protocol on the balance beam.

RESULTS

We observed a greater number of falls from the balance beam from the FG on the first day (5.40 ± 1.14 FG vs 3.33 ± 1.37 CG; p = 0.024) and a decrease in the number of falls on the second day (2.29 ± 1.25 FG water day vs 5.40 ± 1.14 FG carbohydrate day; p = 0.0013). Carbohydrate solution was able to supply muscle demands and improve the athlete's focus showed by the reduced number of falls.

Alterations in serum growth hormone (GH)/GH dependent ternary complex components (IGF-I, IGFBP-3, ALS, IGF-I/IGFBP-3 molar ratio) and the influence of these alterations on growth pattern in female rhythmic gymnasts

BACKGROUND AND AIM

Normal growth in children is regulated to a great extent through the actions of the GH/IGF-I axis, a system consisting of GH and its mediators (ternary complex) that modulate growth in many tissues. The ternary complex (IGF-I/IGFBP-3/ALS) provides an acute regulatory mechanism in which IGF-I may be mobilized from the circulating reservoir of 150 kDa complexes to the tissues. Acute exercise is known to be a stimulus for GH secretion. The beneficial effects of scheduled exercise on body composition are also well established. However, the impact of strenuous exercise on the pubertal development of child athletes is still not well understood. The first goal of this study was to assess the acute effects of high intensity exercise training on GH-dependent ternary complex components in female rhythmic gymnasts compared to age-matched healthy female controls with normal physical activity. The second goal was to explore the influence of these exercise-induced changes on skeletal and pubertal growth in the same group prospectively over a period of 4 years.

SUBJECTS AND METHODS

Seventeen female rhythmic gymnasts, aged 11.4 +/- 0.9 years, who had 10 h per week intense exercise for at least 4 months volunteered to participate in this study. Anthropometric measurement of height (Height SDS for chronological age [HtSDS(CA)], parentally adjusted height, predicted adult height), bone age and weight (BMI) were made using standard techniques in gymnasts and controls (aged 12.5 +/- 3.0 years, n = 12). Gymnasts were followed up to 4 years to observe growth velocity and pubertal progression. In order to determine the acute impact of exercise on levels of GH and GH-dependent ternary complex component (IGF-I, IGFBP-3, ALS, IGF-I/IGFBP-3 molar ratio), blood samples were obtained from gymnasts after a routine 2-h high-intensity training program and then after a 2-day rest period. These results were compared with age-matched controls with no scheduled sports activity.

RESULTS

Despite the significant increment in serum GH and GH-dependent components immediately following the exercise, serum GH/IGF-I levels showed a significant decrement (p < 0.01) after a 2-day rest in gymnasts, to a nadir as low as those of the control subjects' baseline levels (p < 0.01). There was no difference in anthropometric characteristics of gymnasts and controls except BMI; gymnasts were leaner than controls. During a 4-year follow up, there were no differences between the gymnasts and controls in regard to skeletal growth and reaching their predicted height. However, in gymnasts there was a delay in pubertal tempo but not in growth.

CONCLUSION

Intense exercise induces an acute rise in GH levels, but this acute elevation rapidly normalizes after a 2-day rest in female rhythmic gymnasts. These fluctuations in serum GH and GH-dependent ternary complex components had no reflection on the skeletal growth patterns in gymnasts over the 4-year follow up but there was a delay in their pubertal progression.

Growth and pubertal development in children and adolescents: effects of diet and physical activity

The longitudinal growth of an individual child is a dynamic statement of the general health of that child. Measurements should be performed often and accurately to detect alterations from physiologic growth. Although any single point on the growth chart is not very informative, when several growth points are plotted over time, it should become apparent whether that individual's growth is average, a variant of the norm, or pathologic. Somatic growth and maturation are influenced by several factors that act independently or in concert to modify an individual's genetic growth potential. Linear growth within the first 2 y of life generally decelerates but then remains relatively constant throughout childhood until the onset of the pubertal growth spurt. Because of the wide variation among individuals in the timing of the pubertal growth spurt, there is a wide range of physiologic variations in normal growth. Nutritional status and heavy exercise training are only 2 of the major influences on the linear growth of children. In the United States, nutritional deficits result from self-induced restriction of energy intake. That single factor, added to the marked energy expenditure of training and competition for some sports, and in concert with the self-selection of certain body types, makes it difficult to identify the individual factors responsible for the slow linear growth of some adolescent athletes, for example, those who partake in gymnastics, dance, or wrestling.

Growth and pubertal development in elite female rhythmic gymnasts

Optimal growth depends upon both environmental and genetic factors. Among environmental factors that could alter growth and sexual maturation are stress and intensive physical training. The influence of these factors has been documented in a variety of sports, but there is limited information on rhythmic gymnasts, who have entirely different training and performance requirements. The study was conducted during the 13th European Championships in Patras, Greece, and included 255 female rhythmic gymnasts, aged 11-23 yr. The study included measurement of height and weight, assessment of breast and pubic hair development, estimation of body fat and skeletal maturation, and registration of menarcheal age and parental height. Gymnasts were taller than average height for age, with mean height above and mean weight below the 50th percentile. Actual height SD score was positively correlated to weight SD score (P < 0.001), number of competitions (P = 0.01), and body mass index (BMI; P < 0.001). Predicted adult height SD score was positively correlated to weight SD score (P < 0.001) and negatively to body fat (P = 0.004). There was a delay in skeletal maturation of 1.3 yr (P < 0.001). Pubertal development was following bone age rather than chronological age. The mean age of menarche was significantly delayed from that of their mothers and sisters (P = 0.008 and P = 0.05, respectively), was positively correlated to the intensity of training and to the difference between chronological age and bone age (P < 0.001 and P = 0.002, respectively), and was negatively correlated to body fat (P < 0.001). In the elite female rhythmic gymnasts, psychological and somatic efforts have profound effects on growth and sexual development. Despite these aberrations, adult height is not expected to be affected.

Working with young athletes: views of a nutritionist on the sports medicine team

Athletes are influenced by coaches, other athletes, media, parents, the national sport governing body, members of the sports medicine team, and the athlete's own desire for success. It is impossible, therefore, for one member of the sports medicine team to unilaterally determine workable solutions that enhance performance and diminish health problems in an athlete. A focus on ensuring that the athlete can perform to the best of her ability is a key to encouraging discussion between the nutritionist, athlete, and coach. Using the assumption that health and top athletic performance are compatible, this focus on performance provides a discussion point that all parties can agree to and, if approached properly, also fulfills the nutritionist's goal of achieving optimal nutritional status. Membership on the sports medicine team mandates that the nutritionist know the paradigms and health risks associated with the sport and develop assessment and feedback procedures specific to the athlete's needs.