Biomedical subjects
M Ostyn
Publications and source records attributed to M Ostyn.
Physical activity and growth, maturation and performance: a longitudinal study.
The effects of increased physical activity upon physical growth, maturation and performance were investigated in samples of 32 active and 32 nonactive Belgian boys followed longitudinally from 13 to 18 yr of age. Active boys participated in sports activities for more than 5 h.wk-1.yr-1 during each of the first 3 yr of the study, in addition to compulsory physical education. Nonactive boys participated in less than 1.5 h.wk-1.yr-1 during the first 3 yr of the study, but did participate in required school physical education. Anthropometric dimensions included lengths, breadths, circumferences, and skinfolds. A physical fitness test battery was administered at each observation including nine health- and performance-related tests. Skeletal maturation was assessed; sociocultural determinants and sports participation were obtained through written questionnaires verified by a control interview. No significant effects of increased physical activity were observed on growth in somatic dimensions, including skinfolds, age at peak height velocity, skeletal maturation, and most of the physical fitness components. More active boys obtained better results from 14 yr onward only for pulse recuperation and for bent arm hang. These results can be generalized to the average population but do not necessarily apply for highly trained and selected elite athletes.
Failure to induce ovulation with clomiphene citrate and bromocriptine in luteal deficient women athletes.
This study was designed with a three-fold aim: to assess ovarian function of women athletes with menstrual irregularities (AMI); to evaluate the potentiality of clomiphene citrate and bromocriptine for the induction of ovulation in these women; and to show that ultrasound scanning offers a suitable technique for ovarian screening in healthy and high-performance athletes. Our small test group consisted of 11 women, mainly track athletes, with AMI. There was no significant difference in age at menarche (13.2 yrs +/- 0.2), percent of ideal body weight (92% +/- 4), or percent of body fat (12.3% +/- 2.8) among the subjects. Plasma estradiol values were low (mean: 22 pg/ml +/- 0.8), as those of plasma progesterone (2.85 ng/ml +/- 2.10), LH (5.6 mIU/ml +/- 0.8), and prolactin (10.89 ng/ml +/- 5.56). The mean distance run per week (35 km +/- 15) was relatively high considering the presence of 4 non-runners. All menstrual irregularities were attributed to exercise. A short luteal phase (7 days +/- 1.5 for a cycle with a mean duration of 25 days +/- 1.8) was found in all subjects. We failed to observe the presence of a corpus luteum in 9 out of 11 women. A two-month administration of clomiphene citrate (150 mg/d for 5 days) or bromocriptine (2.5 mg/d) did not succeed in provoking ovulation in any of these women. Ultrasonographic observations showed a continuously hypo-estrogenic endometrium with a consecutively developing and regressive follicle. Our data emphasize the difficulties inherent in the restoration of menstrual function in women athletes with AMI. In addition, the usefulness of ultrasound in screening ovarian function was confirmed.
Are high-performance young women athletes doomed to become low-performance old wives? A reconsideration of the increased risk of osteoporosis in amenorrheic women.
Osteoporosis and athletic amenorrhea are now well-established findings in top level women athletes. Specifically trabecular bone appears to be affected. Since these two phenomena seem to occur simultaneously, questions have been raised as to the underlying mechanisms and whether physical exercise, which had been proven to exert a positive beneficial effect under normal conditions, should be held responsible. Although hypo-estrogenic status, body composition, and nutritional deficiency have been offered as possible explanations, none of these can be solely regarded as completely satisfactory. As for athletic amenorrhea itself, low estrogens are probably secondary to other phenomena and may only be related indirectly to osteoporosis. Whether they interfere with nutritional uptake is obscure. Possibly, endogenous opioid peptides are involved as an unnegligible mediator. As an important practical consequence it should be pointed out that osteoporosis in women athletes will be only detected incidentally; a fact which could obstruct timely intervention, though whether therapy is necessary remains open to discussion. The discovery that amenorrheic athletes subject to more severe training have a higher bone density than less engaged amenorrheic colleagues, can only be in favor of physical exercise, even under these conditions.
The monitoring of the menstrual status of female athletes by salivary steroid determination and ultrasonography.
This study was designed to evaluate whether traditional plasma hormone determinations can be adequately replaced by measurements of salivary hormones. Eleven young sportswomen with menstrual irregularities attributed to strenuous physical exercise participated in this study. Mean body weight expressed as a percentage of ideal body weight was 92%, SD 4%. Their mean weekly training distance was 35 km, SD 15. Basal plasma endocrinological measurements revealed a hypo-oestrogenic status (mean plasma oestradiol values: 22 pg.ml-1, SD 8.8), and a deficient luteal phase (mean plasma progesterone: 2.9 ng.ml-1, SD 2.1). Pre-exercise salivary sex steroids were low. Salivary progesterone levels were 39.3 pg.ml-1, SD 9.5 (normal ranges in saliva: 25-60 pg.ml-1), salivary oestrone (E1) was 12.2 pg.ml-1, SD 2.3 (normal ranges in saliva: 7.5-25 pg.ml-1), and salivary oestradiol (E2) less than 1.9 pg.ml-1, SD 1.1 (normally 1.0-10.0 pg.ml-1). After a 21-km run, all salivary steroids appeared to increase. Mean salivary testosterone levels increased by 15.2% and salivary progesterone by 14.8%. Mean salivary oestrogens also increased (E1: +13.9%; E2: +21.1%). These findings confirm the results of earlier studies which found higher post-exercise plasma sex steroid levels. Since salivary measurements are believed to reflect non-protein-bound, thus free steroid levels, the results obtained by these techniques may provide a more realistic picture of the hormonal effects of physical exercise. In future, more accurate, cost-effective and easier techniques for salivary measurements may offer additional advantages.
Suitability of cyproterone acetate in the treatment of osteoporosis associated with athletic amenorrhea.
The effectiveness of the antiandrogenic agent cyproterone acetate (CA) in its contraceptive form (2 mg CA + 50 micrograms ethinyl estradiol) in the treatment of osteoporosis associated with athletic amenorrhea was studied in seven high-performance athletes. Four women with similar characteristics served as controls. Their mean age was 21.9 years +/- 3.9. Training was started at a mean age of 14.0 years +/- 2.0. The mean training intensity expressed as kilometers run per week was 35 +/- 15. Mineral density was primarily affected by the hypoestrogenic status of these athletes (= 22 pg/ml +/- 8.8 in the midluteal phase). All participants showed low serum progesterone (= 2.85 ng/ml +/- 2.10) and LH profiles (= 5.6 mlU/ml +/- 0.8) during the midluteal phase. Cyproterone acetate was administered for 8 months to treat the increased bone loss in seven women athletes. Vertebral density appeared to be increased with 9.5% +/- 2.45% (mean +/- SD) while cortical base mineral content measured at the radius was not significantly changed. Our results demonstrate that cyproterone acetate administered in combination with estrogens provides a suitable therapeutic agent in the management of osteoporosis due to a hypoestrogenic status. This treatment could substitute other contraceptive agents. Moreover, women with the most severe estrogen deficiency showed a more pronounced reaction to this therapy.
Somatotype as related to age at peak velocity and to peak velocity in height, weight and static strength in boys.
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The relationship between psychosocial factors and sports injuries.
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Fatness, growth and motor fitness of Belgian boys 12 through 20 years of age.
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Fatness and skeletal maturity of Belgian boys 12 through 17 years of age.
Relationships between fatness and skeletal maturity are considered in a nationwide sample of 14,259 Belgian boys 12 through 17 years of age (The Leuven Growth Study of Belgian Boys). Absolute fatness was estimated from four skinfolds using the Drinkwater and Ross technique and from the sum of four skinfolds, and was related to skeletal maturity assessed by the Tanner-Whitehouse method (I and II). In addition, comparisons were made between the fattest 5% and leanest 5% of the boys at each age level. Correlations between the indices of fatness and skeletal age and relative skeletal age (the difference between skeletal and chronological ages) are positive and generally low, ranging from 0.12 to 0.39. They tend to decrease with age from 12 to 17 years. Comparisons between the extreme groups indicate that the leanest boys are more delayed in skeletal maturity, by about 0.8 years, than the fattest boys are advanced, by about 0.5 years. Stature data for the same boys are consistent with the skeletal maturity data and thus suggest that the size differences between the extreme groups are due in part to maturity differences. Over the age span 12 through 20 years, the leanest boys are reduced in stature by about -1.2 standard deviations, while the fattest boys are larger in stature by about +0.6 standard deviation units. The size differences, however, persist after skeletal maturity is attained so that there may be a specific role for fatness in influencing statural growth.
Skeletal maturation and physical fitness of 12 to 15 year old boys.
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[Skeletal age and physical development of 12-year-old boys].
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Serum free thyroxine and binding-proteins after muscular exercise.
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[Observations on arterial blood pressure in young adults].
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Chronological and biological age as related to physical fitness in boys 12 to 19 years.
The relative importance of skeletal age and chronological age in explaining body measurements and the relative importance of skeletal age, chronological age, height, weight, and their interactions in explaining motor fitness components are reported. Anthropometric, motor fitness, and skeletal maturity data have been collected in a mixed longitudinal study of Belgian school boys 12+/- - 19+/- years. At each age level multiple regression equations were calculated to evaluate the relative importance of the independent variables. Skeletal age was assessed by the TW2 method and the anthropometric measurements were taken following standard procedures. The motor fitness tests were selected on their factor loading and reliability in the same age range. Between 13 and 16 years a fairly high percentage of the variation in body dimensions is explained by skeletal age (+/-50% for stature). The percentage of explained variance reaches its maximum at 14-15 years. The highest percentage is found for linear dimensions and weight followed by bone width dimensions and circumferences. Triceps and calf skinfolds are not related to skeletal age. Chronological age as such does not contribute in the prediction of body measurements. The interaction between chronological age and skeletal age as such or in combination with height and/or weight have the highest predictive value except for trunk strength (leg lifting) and functional strength (bent arm hang). Except for static strength (arm pull), for which the explained variance ranged from 33% to 58%, the predictive value of body size, maturity, chronological age and their interactions is rather low, varying between 0% and 17%. As for body dimensions, the explained variance reaches its maximum for most motor tests at 14-15 years.
Patterns of TW-1 and TW-2 skeletal age differences in 12-19-year-old Belgian boys.
The pattern of differences between TW-1 and TW-2 skeletal ages was investigated in a mixed longitudinal sample of Belgian school boys aged about 12-19 years. The differences between the TW-1 and TW-2 skeletal ages decrease from 12 years until 15 years, then increase until they stabilize at 17 years. TW-1 skeletal ages are greater than TW-2 skeletal ages, except at 14 and 15 years. This trend confirms the findings in better-off black and white Philadelphia children and in disadvantaged Mexican children (Malina and Little 1981).
Skeletal maturity in Belgian youths assessed by the Tanner-Whitehouse method (TW2).
Reference data for skeletal maturity (TW2 method) of the hand and wrist are provided for large representative samples of Belgian boys and girls. The sample of Belgian boys consisted of 21,174 boys aged 12 to 20 years studied in a nationwide cross-sectional and longitudinal study on the physical fitness of secondary schoolboys (1969-1974). The girls' sample consisted of 9698 6-19-year-old Flemish girls studied cross-sectionally (1979-1980). Both samples were multi-stage stratified cluster samples of entire school classes. All skeletal maturity assessments of the boys were made by the same observer (GB). His estimations agreed quite closely with those of the originators of the method. The skeletal age assessments of the girls were made by two observers trained by GB. Both observers showed high intraobserver reliability after training, and during the assessments. Moreover their ratings compared favourably with those of GB and the originators of the method. Smoothed percentile curves of the maturity scores (TW2-20 bone, RUS and CARP scores) were calculated by means of cubic splines using a stepwise regression procedure for the selection of suitable knots. In the boys, the TW2 scores (20 bone and RUS) increase linearly between 12 and 14.5 years of age, slow down for a while, and then increase again, while the CARP scores increase linearly between 12 and 15 years of age. In girls, the 20-bone maturity scores increase nearly linearly from 6 through 9.5 years of age, accelerate until 11.0 years followed by a smaller increase; RUS scores increase curvilinearly from 6 years of age onwards; and Carp scores increase almost linearly between 6.0 and 12.5 years of age. Belgian boys are advanced in RUS scores but are delayed for the carpal bones as compared with the British standards. The Belgian girls show advancement for both scales as compared with the British reference data. The skeletal maturation of youths from several other continental European countries corresponds more closely with the Belgian than with the British data. The reference data presented herein most probably provide suitable standards for youths of West-European countries.