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Biomedical subjects

W B Erich

Publications and source records attributed to W B Erich.

31 records · Page 2Linked to original sources
PubMed1985

Renin-angiotensin system: oral contraception and exercise in healthy female subjects.

The effect of oral contraception and of exercise on the renin-angiotensin system was studied in 20 highly trained athletes, of whom 10 were ingesting oral contraceptives (users) and 10 were not (nonusers), and in 24 sedentary age-matched healthy female subjects, of whom 13 were users and 11 were nonusers. No training-related effects were observed with the exception of renin substrate, which was significantly higher in the athletes. The plasma concentrations of active renin and of trypsin-activatable prorenin were significantly lower in the subjects taking oral contraceptives. Renin substrate, however, was significantly higher in the oral contraceptives group. No difference in plasma renin activity (PRA) was observed between users and nonusers. The results demonstrate the well-known estrogen-induced stimulation of renin substrate synthesis by the liver and suggest a decreased secretion of renin by the kidney. Exhaustive exercise of short duration, performed by the trained athletes only, stimulated the renin-angiotensin system. An increase in PRA and in active renin concentration was observed. The prorenin concentration did not change significantly. The magnitude of the exercise-induced changes was considerably influenced by oral contraceptive medication. Nonusers showed a significantly greater increase in PRA and active renin and total renin concentration than users. Renin substrate decreased significantly during exercise in the nonusers only. These results demonstrate that oral contraceptives have a suppressive effect on renin secretion at rest, an effect that becomes more prominent during exercise, i.e., physiological stimulation.

Adult↗
PubMed1985

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.

Adipose Tissue↗
PubMed1984

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.

Adolescent↗
PubMed1984

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.

Adipose Tissue↗
PubMed1984

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).

Anthropometry↗
PubMed1984

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.

Body Height↗
PubMed1984

Effect of exercise and oral contraceptive agents on fibrinolytic potential in trained females.

It has been shown that physical exercise increases blood fibrinolytic potential, primarily by inducing a release of extrinsic plasminogen activator from the vessel wall. Synthetic estrogens have also been reported to influence fibrinolytic activity. The effect of exercise and the possible additional effect of oral contraceptive agents (OCA) on the fibronolytic system were studied in 20 competitive female rowers. Ten females used OCA (users), and 10 others did not (nonusers). All participants were subjected to standardized exhaustive exercise. Preexercise data revealed higher factor XII, total plasminogen, and free plasminogen levels together with a significantly lower C1-inactivator level in the group of users. No differences were observed in prekallikrein, high-molecular-weight kininogen, alpha 2-antiplasmin, alpha 2-macroglobulin, antithrombin III, and histidine-rich glycoprotein plasma levels. The factor XII-dependent fibrinolytic activator activity and the extrinsic (tissue-type) plasminogen activator were significantly higher; however, the urokinase-like fibrinolytic activator activity was significantly lower. These observations suggest a greater susceptibility to activation of the fibrinolytic pathways during OCA medication. Exercise resulted in a decrease of all factors under study but an increase in all fibrinolytic activities. No differences were observed between the two groups in the percentages of change that occurred with exercise.

Adult↗
PubMed1983

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.

Adolescent↗
PubMed1982

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.

Anthropometry↗
PubMed1982

Oral contraceptives and fibrinolysis among female cyclists before and after exercise.

The effect of oral contraceptives on a number of plasma fibrinolytic variables and antithrombin III was studied in 20 highly trained women before and immediately after exhaustive exercise on a bicycle ergometer. Two groups were studied, 11 women using an oral contraceptive agent (OCA group) and 9 women not using an oral contraceptive (control group). Factor XII, prekallikrein, plasminogen, alpha 2-antiplasmin, and antithrombin III activities were determined in plasma as well as a number of cardiovascular, respiratory, and metabolic components. Resting values showed a significantly higher level of prekallikrein and plasminogen in the OCA group compared with the control group. Exercise plasma values of components of the fibrinolytic system were significantly higher than resting values in both groups. However, when corrected for plasma volume changes, the exercise levels of prekallikrein and antithrombin III were significantly decreased in the OCA group only, whereas alpha 2-antiplasmin exercise level was significantly lower in both groups. Our results indicate that use of OCA even with an estrogen dosage as low as 30 micrograms has an effect on resting and exercise fibrinolytic variables; an effect, however, which does not seem to interfere with maximal performance in trained women.

Adolescent↗
PubMedDate not supplied

Sports injuries in school-aged children. An epidemiologic study.

In November 1982, epidemiologic data were collected in a unique, large scale, population-based survey on sports injuries in school-aged children living in Holland. A total of 7,468 pupils, aged 8 to 17, completed questionnaires covering a retrospective period of 6 weeks. Seven hundred ninety-one sports injuries were registered, amounting to an incidence of 10.6 sports injuries per 100 participants. In 31% of the cases, medical consultation was needed. Injuries incurred during the study period caused 36% of the children to miss one or more physical education classes and caused 6% to miss school for at least 1 day. Contusions and sprains were the most common lesions (77%). Three of four injuries involved the lower extremity, in particular the ankle. Sixty-two percent of all the injuries occurred in organized sports, 21% in physical education classes, and 17% in unsupervised sports activities. The highest injury rates were found in basketball and field hockey. In this study population, 15 and 16-year-old boys who had a high sports activity index and played team sports, particularly contact team sports, formed a high risk group.

Adolescent↗
PubMedDate not supplied

Injuries in high-risk persons and high-risk sports. A longitudinal study of 1818 school children.

In this Dutch population-based study we attempted to determine the incidence and severity of sports injuries occurring during different kind of sports in a longitudinal way. The study included 1818 school children aged 8 to 17 years. Over a period of 7 months, 399 sports injuries were reported in 324 youngsters. The most common types of injuries were contusions (43%) and sprains (21%). Medical attention was needed in 25% of all cases. Young basketball, handball and korfball players had a nearly 100% chance of suffering one sports injury per year. Volleyball especially had a high incidence rate in practice (6.7 in 1000 hours). Although physical education classes had a low incidence rate, there were significantly more fractures on the upper limb. Etiologically, sports-related factors were much more important than personal-bound factors. The injured youths spent more time in practice than the noninjured ones, both in organized and nonorganized sports (P less than 0.001). High-risk sports were characterized by contact, a high jump rate, and indoor activities. These three factors explained 78% of the total variance. The contact versus noncontact factor accounted for 48% of the medically treated injuries. An additional goal of this study was to explore the seasonal influence as an extrinsic environmental factor. We found that the duration of injury was increased in the spring (P less than 0.05). Specific preventive measures were formulated in order to reduce the number of new and recurring injuries and a proposal was made to implement injury prevention in school curriculums.

Adolescent↗