Schweizerische Zeitschrift fur Sportmedizin最新文献

Blood lactate recovery curves from muscular exercise can be described by a sum of two exponential terms consisting in a rapidly increasing and a slowly decreasing component. A two-compartment model consisting of the previously working muscles and the remainder of the lactate space furnishes the simplest but nevertheless realistic explanation of this evolution pattern. The velocity constants of the rapidly increasing (gamma 1) and the slowly decreasing (gamma 2) components inform respectively on the abilities of the body to exchange and remove lactate. However the blood lactate recovery curves observed in three untrained subjects after 3-min 107-115% VO2max cycling display a transitory plateauing of the lactate concentration between the increasing and decreasing phases of the curves. This levelling off of the concentrations at their highest value was not observed in an endurance trained subject after a 3-min 107% VO2max exercise. Despite the plateauing and consequent less good fit than to the usual evolution curves, the recovery curves could still be accurately fitted by the biexponential time function. After supramaximal exercise the abilities to exchange and to remove lactate are severely impaired. These impairments in the functional properties of the organism are very likely associated with and/or linked to physico-chemical modifications which have been observed as much at the cellular level as in the body fluids during and after supramaximal exercise.

Based on an important statistic of mountain frostbite (1260 cases), the authors try to explain the underlying physiopathological mechanism which remains largely unknown. An early prognosis may nowadays be improved by several diagnostic tools whose efficiency is reviewed. Difficult problems arise with severe frostbite only. In those cases, the treatment as such seems still limited to saving what has been spared. In any case, a quick warming up is the keystone of the treatment.

It is a common belief that snowboarding might carry a higher risk of accident than alpine skiing. In order to prove this suspicion but also to figure out a basic knowledge to develop special security precautions for snowboarding 204 snowboarding-accidents in the Alps have been registered and analysed. The major purpose of this study was to find out the crucial points of risks of this new way of performing winter sports and to compare these risks with the risk-profile of alpine skiing. These have been the main results: More than two thirds of all accidents happen on icy or hard courses. Few more than the half of all injuries affect the lower extremity, one third the upper extremity whereby injuries of the ankle, knee, shoulder and hand emphasize. Strains and fractures are placed in the foreground. Two thirds of all injuries of the lower extremity affect the front of the leg, whereby nearly two thirds of all leg-injuries result from a mechanism which is a combination between bending forward and torsions. Depending on the different types of boot characteristic crucial points have been shown with injuries of either the ankle or the knee. As a principal demand for better safety at least for beginners a functional safety-binding should be developed. Regarding to the most common critics that snowboarding will increase the incidence of collisions (on-course) and avalanche-accidents (off-course), this study could fortunately not prove these suspicions.

The medical profession seems to be more and more convinced of the beneficial effects to the child elicited by a sports activity at any age not only as morphological adaptation, but as psychological improvement too. For the sickly child, a given sport can be very helpful for his psychological development, as it gives him the means to show his abilities, to overcome his handicap and thus master his health problem. The general practitioner therefore should not prohibit going for sports. To the contrary, he should encourage, even prescribe outdoor games to the child. The child has to be carefully instructed as to how to carry out the chosen sport. We cannot put too much emphasis on the fact such as exercise treatment can only be successful if the children are particularly motivated and have been briefed. We have selected nine illnesses which include very often the bulk of the exemptions from the physical education lessons at school. We listed for each disorder a series of sports and various outdoor activities under the following headings: --activities to be recommended, --sports of lesser therapeutic value, or not to be recommended under some circumstances, --sports without demonstrated beneficial effects, or to be advised strongly against. Episodic exercise contributes certainly nothing to stabilizing the symptoms of the disease in patients suffering from a chronic disorder. To the contrary, a training program maintained for a prolonged period may be very beneficial in improving the wellbeing of the patient. Thorough information, as well as a clear exercise program which should be done in some cases under medical supervision is needed. One should keep in mind however, that any problems arising can be mastered and that the child will take an undeniable advantage of such a treatment.

Following the extensive technical progress in monitoring of sports performance, putting certain physiological principles out of reach for the everyday sportsman, we wondered if perceived effort (PE) as described by Borg is a parameter that is of use, or complementary, to the determination of the anaerobic threshold (AT) during an incremental test on a treadmill on one hand and to prescribing exercise adapted to the type of metabolic load on the other. 46 sportsmen (various soccer players, regional runners) were asked to complete a Conconi Test on a treadmill and at the same time were asked to evaluate their PE (as defined by Borg) at each performance level. We then plotted PE as a function of running speed, thus finding a point of inflexion (ascending) for PE. The speed corresponding to this point shows an excellent correlation with the AT as determined from cardiac frequency. The absolute value of PE at the AT varied little within our group, but seemed to vary according to the type of sport and the subjects' sports practice. Taking the limitations of this method in consideration, PE may be used as an additional indicator in the determination of the AT in an incremental AT-test and can be useful in the prescription of an exercise program.

The role of modern instrumental analysis in today doping control procedures is described. With reference to the analytical methods, to the requirements of the International Olympic Committee for laboratory accreditation and to the regulations for substantiating a positive result, we show how a laboratory for doping control is functioning. The limits of today analyses are shown, making it obvious that the analytical results from an accredited laboratory are not the weak point in doping control.

The reliability of the dope control, of the chemical analysis of the urine probes in the accredited laboratories and their decisions, is discussed using probabilistic and statistical methods. Basically, we evaluated and estimated the positive predictive value which means the probability that an urine probe contains prohibited dope substances given a positive test decision. Since there are not statistical data and evidence for some important quantities in relation to the predictive value, an exact evaluation is not possible, only conservative, lower bounds can be given. We found that the predictive value is at least 90% or 95% with respect to the analysis and decision based on the A-probe only, and at least 99% with respect to both A- and B-probes. A more realistic observation, but without sufficient statistical confidence, points to the fact that the true predictive value is significantly larger than these lower estimates.

Ski accidents are quite frequent but not alarming if we consider the benefit of the outdoor sporting. In the countryside around Davos-Klosters more than 5 Mio kilometers of vertical drop are performed in down hill skiing. They result in approximately 1300 accidents per year. Since 1972 more than 20,000 ski accidents were analysed. The injuries of the lower extremity have decreased slightly (44%), on the other hand we observed more injuries of the upper extremity (32%). There are only a few polytrauma patients registered, mainly on the basis of too high speed on the ski slopes. Fractures have become rather uncommon at least in relation to the complex knee injuries which today amount to 50% of all the injuries of the lower extremities. For the prevention of ski accidents a detailed control of the equipment, especially the safety bindings at the beginning of each winter season is of utmost importance.