Schweizerische Zeitschrift fur Sportmedizin最新文献

Scuba diving is associated with risks of drowning, lung barotrauma and decompression sickness. In case of near-drowning, irreversible neurologic lesions or death may follow an acute hypoxemia or a cardiopulmonary arrest. Therefore, victims of drowning should benefit from an immediate and prolonged cardiopulmonary resuscitation. Lung barotrauma are due to the failure of expanding lung gases to escape during ascent; they are likely to be complicated by arterial gas embolism. They can follow a panic ascent even from a shallow depth. Most of decompression procedures induce the formation of asymptomatic venous gas bubbles, normally filtrated and eliminated by the lungs. In case of massive intravenous bubbling, the filtering capacity of the lungs can be overwhelmed and the lung microcirculation damaged up to the point of provoking a cardio-respiratory failure.

The combination of frequency, intensity, and duration of chronic exercise has been found to be effective for producing a training effect. The interaction of these factors provide the overload stimulus. In general, the lower the stimulus the lower the training effect, and the greater the stimulus the greater the effect. As a result of specificity of training and the need for maintaining muscular strength and endurance, and flexibility of the major muscle groups, a well-rounded training program including resistance training and flexibility exercises is recommended. Although age in itself is not a limiting factor to exercise training, a more gradual approach in applying the prescription at older ages seems prudent. It has also been shown that endurance training of fewer than 2 d/wk, at less than 50% of maximum oxygen uptake and for less than 10 min/d, is inadequate for developing and maintaining fitness for healthy adults. In the interpretation of this position statement, it must be recognized that the recommendations should be used in the context of participants' needs, goals, and initial abilities. In this regard, a sliding scale as to the amount of time allotted and intensity of effort should be carefully gauged for both the cardiorespiratory and muscular strength and endurance components of the program. An appropriate warm-up and cool-down, which would include flexibility exercises, is also recommended. The important factor is to design a program for the individual to provide the proper amount of physical activity to attain maximal benefit at the lowest risk. Emphasis should be placed on factors that result in permanent lifestyle change and encourage a lifetime of physical activity.

For several years now, a controversy has developed on how to position a patient after a decompression accident with acute gas embolism. The usefulness of the so-called Trendelenburg position, based on experimental evidence gathered on dogs, has recently been challenged. The basis assumption was that cerebral embolism may be reduced by the hydrostatic effect of putting the head below the body's center of gravity. This position however required much technical resourcefulness and often delayed the first therapeutic intervention. Newer experimental research shows that, contrary to the old theory, positioning the head below feet level increases the intra-cranial pressure, injuring the blood-brain barrier, even when done under hyperbaric oxygen therapy. A wide consensus has now emerged, which should be communicated to first-aid personnel, so that no more time is being lost in trying to position the accidented diver by unduly complicated means. The current recommendations asks for laying the injured diver horizontally on its back, or sideways, if he is unconscious. It is by far more important to control its vital functions, give first-aid, administer oxygen in closed circuit, and shorten as much as possible transport time to the next center for hyperbaric therapy.

As a tentative investigation of morpho-endocrinology, 92 male and 18 female long-distance runners (ages 21 to 72) were measured according to the standard anthropological techniques. 66 anthropometric parameters, the colours of hair and eyes were recorded. Seven growth factors were derived by means of factor analysis. The levels of 13 hormones were measured and morphological and endocrinological parameters were compared by means of correlation coefficients. So human growth hormone showed correlations to macrosomia and hyperplastic robustness. Estradiol was primarily related to the more feminine features of men, but also to leanness and slenderness of women. Testosterone exhibited significant correlations to mesomorphy and masculinity of males and leptomorphism and strength of females. Both sexes with higher insulin levels seemed to be more fat. Thyroxine (T4) showed a relation to endomorphy and leptomorphism of face, whereas Triiodothyronine (T3) exhibited correlations to ectomorphy. Thyroid stimulating hormone (TSH) was paralleling mesomorphy of males and hyperplastic robustness of females. Luteinizing hormone (LH), Follicle-stimulating hormone (FSH) and Prolactin were related to microsomia and hypoplasia. The T4 levels of the dark-haired athletes were significantly higher than the levels of the bright-haired. Several correlations between morphology and hormonal status have been shown, which may be interpreted as a permanent endocrine constitution paralleling the somatotypical body shape, outlasting growth. These correlations however should not be interpreted as causal, as further experimental studies are needed to ascertain such a link.

Between 1978 and 1984, 1323 high level athletes were tested at the Sports sciences institute of the Swiss federal sports school. During these investigations, several characteristic variations of body statics were measured. Analysis of the pooled data reveal a link of statistical significance between certain sports and several abnormalities of lower limbs static. As it was a retrospective investigation, we cannot be sure of a causal relationship between the reported effects. Our principal aim however was to publish this somewhat extensive set of data, in view of the general dearth of such scientific results. In addition to the type of movement the athletes perform during their sports activity, it is the duration of the exertion which seems to be an important determinant for the presence of an increased number of static abnormalities in certain sports. Endurance running presents an elevated risk of developing both flat foot and splay foot. For football (soccer) and tennis players however, only a subnormal transverse foot arch appears frequently. Alpine skiers on the other hand have an increased risk of longitudinal foot arch insufficiency. The knowledge as to which abnormalities are increasingly present in a given sport is instrumental to enabling an early detection and prophylaxis of these ailments.

In case of a type II decompression sickness (with cerebrospinal injury), the decision on how to structure a prompt hyperbaric treatment rests on an anamnesis and the clinical investigation. In looking for an associated contingent barotrauma, one has to be satisfied with an X-ray of thorax and abdomen. The myelopathy which results from a decompression mishap with medullary involvement forms a very peculiar clinical entity defined by a fascicular injury at several levels. For several years now, clinical radiologists resort to a new medical imaging technique: Nuclear Magnetic Resonance (NMR-)Imaging. For the first time, this technique allows the imaging of intramedullary lesions due to a decompression accident. Other neuroradiological investigations (such as myelography, spinal tomodensitometry, medullary angiography, isotopic tests) are without merit for evaluating decompression accidents with medullary involvement. NMR-Imaging has the potential too, of revealing ischemic cerebral injuries, even if the clinical brain impairment is often silent and therefore overlooked. The role of NMR-Imaging for evaluating cerebrospinal aspect of decompression accidents is not yet finalized. However, NMR-Imaging will give without any doubt a boost to the pathophysiological knowledge of decompression mishaps.

Fasting, or zero calorie diets are used not only by overweight people as a means of losing weight, but by athletes too. Their use is then explained on philosophical grounds, with the aim of even enhancing sports performance. The purpose of this investigation consisted of quantifying the effects of a 10-day fast on maximum performance capacity and endurance (as measured on a bicycle ergometer) of 12 female students of physical education of normal weight. The measurements included resting and exercise metabolism determinants, as well as weight and lean body mass. The main results show that after the diet period the maximum ergometric performance was lower in absolute terms as well as in relation to weight or lean body mass. Performance capacity for submaximal exercise was also reduced. Fat combustion was enhanced both at rest and during exercise. The reduction of maximum performance and endurance capacity may be explained by an enhanced muscle breakdown, an efficiency drop of muscular work, and an inadequate glycogen content of the acting muscles. Shorter fasting periods of 24-36 hours also lead to a lower performance level for exercise bouts extending from several minutes to 1-3 hours. An enhancement of fat combustion was always conspicuous. One may conclude that optimal physical performance is dependent on full hepatic and muscle glycogen stores. Glycogen concentration in the liver decreases sharply as a matter of fact after merely one day of carbohydrate shortage. Zero calorie or low carbohydrate diets are thus at variance with an optimal physical work capacity.

Selenium which has been recognised as an essential trace element for mammals and humans is part of the enzyme glutathione peroxidase (GSHPx) and of other selenium-dependent enzymes. GSHPx protects the organism from oxidative damage. Supposing that the formation of peroxides is enhanced in athletes during a marathon run the question arose whether the selenium concentrations in the blood plasma and the GSHPx activities in the erythrocytes are changed. Our experiments were performed with 13 athletes completing a marathon. Blood probes were taken before, immediately after and two hours after the endurance event. No significant changes in the selenium concentrations of the blood plasma probes nor of the enzyme glutathione peroxidase activities of the erythrocytes were observed during the experiments. The selenium concentrations in the plasma: 77.7 +/- 20.8 micrograms/l and the GSHPx activities of the erythrocytes 18.2 +/- 7.4 U/g Hb were within normal clinical range. Symptoms of selenium deficiency could not be detected. In order to answer the question of whether the selenium concentrations in the blood of the athletes represent an optimal level for preventing enhanced formation of peroxides, intervention studies are needed, including measurement of more parameters of lipid peroxidation.