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Biomedical subjects

N W Constantini

Publications and source records attributed to N W Constantini.

7 recordsLinked to original sources
PubMed2006

Rapid recovery from acute transverse myelitis in an elite female swimmer.

Rubella is now an uncommon disease, and its neurological complications are rarely encountered. One complication, acute transverse myelitis, has been described in a few case reports and usually has an unfavourable outcome. The case is presented of an elite swimmer who developed transverse myelitis after rubella, which was treated with methylprednisolone. The recovery was so rapid and complete that two months after the acute event she broke a national swimming record.

Adult↗
PubMed2000

The effect of glycemic index on plasma glucose and lactate levels during incremental exercise.

Consumption of low glycemic index (GI) foods before submaximal endurance exercise may be beneficial to performance. To test whether this may also be true for high intensity exercise, 10 trained cyclists began an incremental exercise test to exhaustion 65 min after consuming equal carbohydrate portions of glucose (HGI), pasta (LGI), and a noncarbohydrate control (PL). Time to fatigue did not differ significantly (p = 0.05) between treatments. Plasma glucose concentration was significantly lower after LGI vs. HGI from 15 to 45 min of rest postprandial. During exercise, plasma glucose concentration was significantly lower after HGI vs. LGI from 200 W until exhaustion. Plasma lactate concentration following HGI was significantly higher than PL from 30 min of rest postprandial through to the end of the 200-W workload. Plasma lactate concentration following LGI was significantly lower than after HGI from 45 min of rest postprandial through to the end of the 100-W workload. At higher exercise intensities, there was no significant difference in plasma lactate levels between treatments. These findings suggest that a high GI carbohydrate meal (1 g/kg body wt) 65 min prior to exercise decreases plasma glucose and increases plasma lactate levels compared to a low GI meal, but not enough to be detrimental to incremental exercise performance.

Adult↗
PubMed2000

Iron status of highly active adolescents: evidence of depleted iron stores in gymnasts.

Much attention has focused on the nutrition and hematological profile of female athletes, especially gymnasts. The few studies on iron status of male adolescent athletes found a low incidence of iron deficiency. The present studies investigated the iron status of male and female gymnasts (G) and compared it with athletes of other sports. Subjects were 68 elite athletes (43 M, 25F) ages 12-18, of four sports: gymnasts (11M,12F), swimmers (11M,6F), tennis players (10M,4F), and table tennis players (11M,3F). All lived in the national center for gifted athletes, trained over 25 hr a week, ate in the same dining room, and shared a similar life style. Mean levels of hemoglobin (Hb), red blood cell indexes, serum ferritin, serum iron, and transferrin were measured in venous blood. There was no difference in mean Rb among gymnasts (G) and nongymnasts (NG). However Hb was less than 14g/dL in 45% of MG vs. only 25% in NG, and less than 13g/dL in 25% of premenarcheal FG vs. 15% in NG. Low transferrin saturation (<20%) was detected in 18% of MG and 25% of FG vs. 6% and 8% in male and female NG, respectively (p<.05). The percentage of males suffering from low ferritin level (<20 ng/ml) was twice as high in G (36%) vs. NG(19%), and about 30% in all females. In summary, iron stores were consistently lower in MG vs. NG. Adolescent athletes of both genders, G in particular, are prone to nonanemic iron deficiency, which might compromise their health and athletic performance.

Adolescent↗
PubMed1995

Menstrual dysfunction in swimmers: a distinct entity.

Menstrual dysfunction is common among athletes with very low body mass, such as long distance runners and dancers, and is usually associated with hypothalamic dysfunction. The purpose of this study was to investigate the menstrual status of swimmers, in whom exercise is nonweight bearing and thinness is, thus, not essential. Questionnaires recording the menstrual history of 69 young competitive swimmers (aged 16.4 +/- 0.5) were compared to those of 279 age-matched controls. Age of menarche (M) was significantly (P < 0.005) delayed among swimmers (13.8 +/- 0.2 yr) compared to controls (13.0 +/- 0.1 yr). Eighty-two percent of swimmers had menstrual irregularities after M compared to 40% of control, with longer duration of these irregularities (16 vs. 4 months; P < 0.005). A subset of 24 swimmers was studied further for body composition, pubertal stage, and reproductive hormone levels. Estradiol levels were normal in all post-M swimmers (273 +/- 20 pmol/L) and higher than average in pre-M (383 +/- 44 pmol/L). FSH levels were normal in all subjects (10.7 +/- 1.6 IU/L), LH was mildly elevated (17.1 +/- 1.2 IU/L), and the LH/FSH ratio was 1.7. Levels of dehydroepiandrostenedione sulfate and androstenedione, but not testosterone, were higher than average in all groups of swimmers. The results of this study indicate that female competitive swimmers are vulnerable to delayed puberty and menstrual irregularities, but the associated hormonal profile is very different from the hypothalamic amenorrhea described in dancers and runners. We, therefore, suggest a different mechanism for reproductive dysfunction in swimmers that is associated not with hypoestrogenism, but, rather, with mild hyperandrogenism. A distinction among the various types of athletic amenorrhea should be made based on hormonal profiles with attention to their weight and somatotype.

Adolescent↗
PubMed1994

Special problems of the female athlete.

The number of women of all ages participating in physical activity is consistently increasing. Although there are numerous benefits to physical activity, specific problems may occur along the various stages of the female athlete's life, which need special attention. A remarkably late menarche, exaggerated beyond the expected genetic predisposition and a high prevalence of abnormal or absent menstrual cycles is seen in athletes, especially in dancers and long distance runners. Reproductive system dysfunction is associated with multiple factors, of which nutritional intake and caloric balance seem to be of a special importance. A high proportion of athletes suffer from pathological eating behaviours and there is an overlap between many features of anorexic patients and highly active athletes. The pathophysiology seen in most cases is hypo-oestrogenism due to suppression of the GnRH pulse generator. The mechanism(s) causing this reversible hypothalamic dysfunction are yet unknown. Of major concern are the skeletal abnormalities, including failure to reach peak bone mass, reduced bone density, scoliosis and stress fractures as a result of prolonged hypo-oestrogenism. Hormone replacement may be indicated in cases in which reduction of exercise or weight gain is not feasible or unsuccessful. Other populations that need special precautions are pregnant athletes and older women.

Adolescent↗
PubMedDate not supplied

Strength profiles and performance in Masters' level swimmers.

The purpose of this study was to profile shoulder, trunk, and thigh strength and shoulder range of motion in competitive Masters' level swimmers and to see if these variables were related to swimming performance. Twenty-four Masters' level swimmers (13 men and 11 women) were tested for isometric trunk flexion and extension, isokinetic knee extension and flexion, shoulder abduction, internal rotation, external rotation, and supraspinatus muscle strength; shoulder internal and external rotation range of motion; and 50-yard swimming time. Strength scores were adjusted for weight. The men were significantly stronger than the women in trunk extension and flexion. Shoulder range of motion, shoulder abduction strength, and thigh strength were equal for both the men and the women. The men were stronger than the women in internal and external shoulder rotation. Conversely, the women tested were significantly stronger than the men in the supraspinatus muscle test. The men were significantly faster than the women in the 50-yard swim. Inverse relationships existed between swimming time and trunk flexion, trunk extension, and shoulder internal rotation strength. Trunk flexion strength remained the only significant predictive variable of swimming time in a multiple regression analysis.

Adult↗