Plasma lipoprotein profile in relation to sex hormones in premenarcheal athletes.

Physical activity of an endurance nature is supposed to affect the lipoprotein profile in adults as well as in children. When examining this profile in premenarcheal athletes, regard has to be paid to an interfering effect of the rising sex hormone levels due to puberty. Therefore, the purpose of this study was to investigate the plasma lipoprotein levels of premenarcheal athletes in relation to their sex hormone profile. Thirty-six elite gymnasts, 21 recreational gymnasts, 27 girl swimmers, and 25 very little active control girls participated. Their age was about 12 years. The sex hormone profiles of all groups were similar. The swimmers had the lowest level of TC, LDL-C, and TG (P less than or equal to 0.05), and apo A-I was elevated in this group as compared with the others (P less than or equal to 0.05). HDL-C was highest in the recreational gymnasts (P less than or equal to 0.05). The elite group and the control group had similar lipoprotein profiles. After adjustment for T and E-2, no change in variance of the lipoproteins was found. A low correlation existed between apo A-I, E-2, and T (P less than or equal to 0.05). Thus, in this pediatric population, the sex hormones did not play a significant role relative to the levels of plasma lipids or apo A-I. As the body composition correlated very weakly with TG, it is tentative to conclude that the variance found in the lipoprotein profile might be due to differences in physical activity. Moreover, genetic factors may have contributed to the variance.

Nutrition of premenarcheal athletes: relation with the lipid and apolipoprotein profiles.

The lipid and apolipoprotein profiles in plasma and the nutritional intake were investigated in 25 female elite gymnasts, 23 recreational gymnasts, 21 girl swimmers, and 16 controls. The girls were matched for sexual development, assessed by means of breast development. The age of the girls varied from 10.0 to 15.0 years. The recreational gymnasts and the girl swimmers had the highest levels of HDL-C, while those of the elite gymnasts and the controls were equally low (P less than or equal to 0.05). The same trend was seen in the case of the HDL-C/TC, HDL-C/LDL-C, and HDL-C/apo A-I ratios (P less than or equal to 0.05). The swimmers and the controls had similar high levels of apo A-I, and the swimmers also had a low apo B level. The differences with the elite group reached statistical significance (P less than or equal to 0.05). The recreational gymnasts had a lower level of apo E than the elite gymnasts and the swimmers had (P less than or equal to 0.05). The composition of the diet, expressed in energy %, was similar for all groups. The recreational gymnasts had a higher P/S ratio than the controls. It is concluded that the differences in lipid and apolipoprotein profiles found between young, female athletes and controls are not associated with differences in dietary intake and may be due to differences in physical activity. Also, genetic factors may have contributed to the variation found in the mentioned profiles. Yet, in this pediatric population, the nutritional intake played a small but significant role relative to the plasma lipids and apolipoproteins.

Socio-economic factors in relation to lipid profiles in young girl athletes.

The influence of socio-economic factors on blood lipid values was studied in 4 groups of young female athletes. Based on type of sport (gymnastics and swimming) and of training intensity, the participants were subdivided into 25 talented, high achievement gymnasts (age 12.3 +/- 1.6 (SD) year), 42 non-talented, low achievement gymnasts (age 12.0 +/- 1.2 (SD) year), 12 high achievement swimmers (age 10.3 +/- 1.6 (SD) year), and 24 low achievement swimmers (age 10.8 +/- 1.6 (SD) year). With respect to socio-economic factors, no significant differences were observed between the two gymnastic groups nor between the two swimming groups. The blood lipid values revealed a significantly higher low density lipoprotein-cholesterol level and significantly lower high density lipoprotein-cholesterol/total cholesterol and high density lipoprotein-cholesterol/low density lipoprotein cholesterol ratios in the talented gymnasts as compared to the non-talented gymnasts. In the high achievement swimmers, low density lipoprotein-cholesterol and triglyceride levels were significantly lower and high density lipoprotein-cholesterol/total cholesterol was significantly higher as compared to the other swimmers. The Spearman rank order correlation coefficients for the relationships between socio-economic factors and blood lipid values were mostly weak or inconsistent. Therefore, no major influence of socio-economic factors on blood lipid values could be demonstrated in the groups investigated.

The influence of physical exercise on growth and sexual maturation in young female rats.

This investigation deals with the influence of physical activity on the growth and sexual maturation of weanling female Wistar rats. It involves three groups of rats, namely an intensively trained group (n = 45), a moderately trained group (n = 49) and a nontrained group (n = 49). The trained groups were forced to perform physical exercise from the age of 15 days on, on a treadmill. Within the intensively trained group, exercise was increased by increasing the speed and grade of the treadmill. The exercise of the moderately trained group was held constant. A delay in the day at vulva opening, indicating sexual maturation is seen in the extensively trained group in comparison with the moderately trained and nontrained group. The average body weight at the day of vulva opening is the same in all groups. However, the correlation coefficient between day at vulva opening and body fat mass is not significant. No differences in the body- and tail-length growth can be detected between the groups. A delay in the sexual maturation due to stress can be rejected since the open fields results registrating stress parameters, as obtained from the various groups of animals, are in general not significantly different between the intensively trained and moderately trained as well as nontrained groups. This investigation shows evidence that intensive physical exercise from young age on, causes a delay in sexual maturation, although it has no influence on the body- and tail length growth.

A retrospective growth study of female gymnasts and girl swimmers.

The aim of this investigation was to retrospectively evaluate growth patterns of different groups of gymnasts as compared to schoolgirls and girl swimmers from 1 until 11 years of age. The gymnastic groups (recreative, young talented, and older talented gymnasts) were smaller than the groups of girl swimmers and schoolgirls already from a young age on. The differences in body height between the groups of sports participants and schoolgirls in the prepubertal period appeared to be mainly based on the genetic growth regulation and seemed to be largely dependent in the gymnastic groups on inheritance of the mothers' height. Significant differences existed in weight as percentage of normal weight for height between the gymnasts and the swimmers. No relations existed between the standard deviation scores, weight percentage, and socioeconomic status. Contrary to general belief, there was no evidence that physical activity from a young age on directly influences growth until puberty.

Apolipoprotein and lipid profiles in young female athletes.

The apolipoprotein and lipid profiles were investigated in 22 female gymnasts, 20 girl swimmers, and 12 controls. The average age of all groups was about 12 years, and the girls were matched for sexual development, i.e., breast development stage m = 1 or m = 2. The gymnasts appeared to have the highest level of HDL cholesterol and the highest HDL cholesterol / total cholesterol, HDL cholesterol / LDL cholesterol and HDL cholesterol/apo A-I ratios in comparison to both the swimmers and the control group. The swimmers had the highest level of apo A-I, but a lipid profile similar to that of the controls. It is concluded that in children, as in adults, regular physical activity affects the lipid and apolipoprotein profiles. In addition, it appears that the apolipoproteins discriminate between trained and nontrained subjects as well as (apo B) or better (apo A-I) than the lipid components of the corresponding lipoproteins (LDL cholesterol or HDL cholesterol).

Biological maturation, body composition, and growth of female gymnasts and control groups of schoolgirls and girl swimmers, aged 8 to 14 years: a cross-sectional survey of 1064 girls.

The aim of this study was primarily to investigate differences in onset and progression of puberty, body composition, and growth between groups of young female gymnasts, schoolgirls and girl swimmers, and secondly to determine the relations between the pubertal events and body composition, especially the amount of body fat, or training activities. In 1980, 1981, and 1982, 668 female gymnasts, 298 schoolgirls and 98 girl swimmers were examined. The gymnasts were subdivided into three different groups, namely, the talented, the nontalented, and the selection group. The onset of puberty and menarche was delayed in the gymnastic groups by about 1 or 2 years compared to the schoolgirls and girl swimmers. The gymnasts were on average smaller than the schoolgirls and girl swimmers. These differences became even more pronounced after the age of 10 years. This may be caused by a delayed growth spurt within the gymnastic groups in combination with self-selection. Furthermore, the gymnasts were leaner than the other two groups: the girl swimmers had a greater fat mass and a greater lean body weight, while the schoolgirls had more fat mass. Relations were found between the parameters of pubertal development and calculated fat mass and also between breast development, pubic hair growth and age, body height, body weight, and calculated lean body weight. Only in the swimming group were training hours per week related to body height, body weight, lean body weight, and pubic hair growth.

Sex hormone profiles of premenarcheal athletes.

Female gymnasts have a delayed onset and probably retarded progression of puberty. The aim of this study was to test the hypothesis that the delay in onset of puberty in gymnasts as compared to girl swimmers is modulated by a lower estrone level due to a smaller amount of body fat. The sex-hormone and gonadotropin levels of 46 gymnasts and 37 girl swimmers of the same biological maturation (breast development: M = 1 or M = 2) were studied. In each subject the following hormones were measured in plasma: estrone, 17-beta-estradiol, DHEAS, testosterone, androstenedione, LH, and FSH. In prepubertal children (M = 1) the levels of estrone, testosterone, and androstenedione were lower in the gymnastic group as compared to the swimming group. In the early pubertal (M = 2) gymnastic and swimming groups these hormone levels were no longer different. The other hormone levels were not significantly different in either the prepubertal groups or the early pubertal ones. Within the total prepubertal group there is a clear relationship between the estrone levels and the levels of testosterone and androstenedione, but not between estrone and 17-beta-estradiol, nor between the calculated fat mass and any of the hormone levels. It appears that the androstenedione and testosterone levels are responsible for the difference in estrone level, rather than the amount of body fat.

Height, body composition, biological maturation and training in relation to socio-economic status in girl gymnasts, swimmers, and controls.

This study examined the height, body composition, prevalence of obesity, biological maturation and training in relation to socio-economic status of 78 female gymnasts (age 138 +/- 18 months), 52 girl swimmers (age 134 +/- 24 months) and 116 control girls (age 131 +/- 21 months). The female gymnasts are shorter and lighter than girl swimmers. They are also shorter than control girls comparing the growth percentiles. The weight to height ratio (w/h) and the Quetelet index are the same for the groups. The female gymnasts have less fat, and a later biological maturation than girl swimmers and controls. The socio-economic status of girl swimmers is lower than that of the control group. Nevertheless the girl swimmers are taller and they have the same biological maturation as the controls. The girl swimmers are even more matured than the gymnasts. The gymnasts have the same socio-economic status as the controls, but they are shorter and less matured. Therefore, in the investigated groups no positive relationship between height and socio-economic status exists. Nor is a low socio-economic status accompanied by a late biological maturation or a higher prevalence of obesity. Training did not correlate with socio-economic status in gymnasts or controls, only in the swimming group a weak correlation was found.

Selection of talented female gymnasts, aged 8 to 11, on the basis of motor abilities with special reference to balance: a retrospective study.

Our aim is to propose a selection procedure on the basis of motor abilities. Within this scope, we have particularly studied balance as one of the selection criteria for young female gymnasts. We have used the combination of two standardized tests: the beam-walking test and the stork-standing test. Four groups of young females (aged 8 to 11 years) were tested. The results indicate that the talented group (n = 23, those participating in national training) has better balance in comparison to the control group (n = 37), gymnasts only participating at club level) and the average group (n = 32, girls not taking part in gymnastics). The results are independent of age, height, and weight, which justify the conclusion that balance is stabilized before the age of 8 years. The fourth group (n = 192) are girls who took part in the selection procedure in 1979 and 1980. We divided this group in 1981 into a non-selected group (n = 121), a discharged, selected young talented group (n = 42), a selected young talented group (n = 16), and an older talented group (n = 13). We discuss the results of these groups at the time of the selection procedure. The two talented groups show better results on the balance tests than the discharged, selected group and the non-selected group. There is no relationship to the results of the total selection test. The results indicate that these tests can be used as one of the selection criteria within the selection procedure for young female gymnasts.