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Biomedical subjects

E Raas

Publications and source records attributed to E Raas.

At least 19 recordsLinked to original sources
PubMed2003

Physical and physiological factors associated with success in professional alpine skiing.

Scientific data on the physiological profile of world class skiers are sparse. During the last decade the Austria Ski Team was the most successful in the world. It was the objective of this study to describe the physical and physiological characteristics of World Cup (WC) skiers. Twenty female and 28 male members of the Austrian WC Ski Team were examined pre- and post-seasonally from 1997 to 2000. Physical parameters such as age, height, body mass, body mass index, percent body fat and thigh circumference were recorded from each athlete. The physiological variables investigated consisted in the aerobic power and in the muscle strength of the lower limbs. Racing performance was defined by the WC ranking position. The athlete's aerobic performance capacity was assessed by maximal exercise testing on a bicycle ergometer, and the isokinetic muscle strength of the knee extensor and flexor muscles by the use of a computer-interfaced dynamometer. From 1997 to 2000 about half (48 %; n = 106) of all alpine WC racing events (n = 221) were won by the athletes investigated. The typical world class skier is in the mid-twenties (25.2 y [female]; 27.6 y [male]). The mean values for height were 1.66 m (female) vs. 1.81 m (male), for body mass 65.1 kg (female) vs. 87 kg (male) and for the percentage of body fat 24.5 % (female) vs. 15.8 % (male). The maximum power output was 4.3 +/- 0.4 (female ) and 4.7 +/- 0.4 W/kg (male), the corresponding values for VO(2)max were 55 +/- 3.5 (female) and 60 +/- 4.7 ml/kg/min (male). The maximal values for peak torque and work for knee extension amounted to 206 +/- 21 (female) and 334 +/- 43 Nm (male), and 2690 +/- 364 (female) and 4414 +/- 629 J (male), respectively. In both sexes there were neither significant laterality nor dysbalance. The hamstring/quadriceps ratios were between 0.57 - 0.60. Among all physical and physiological variables, only the aerobic power in males was found to be strongly correlated (r = 0.947; p = 0.001 for W (max); r = 0.964; p < 0.001 for VO(2)max) to racing performance. The study proves the practical experience that success in professional alpine skiing is not related to single physiological variables. Two main factors, however, are crucial, i. e. high levels of aerobic power and muscle strength.

Adult↗
PubMed2000

Changes in hemoglobin values in elite cross-country skiers from 1987-1999.

Hemoglobin data have been available from ski teams beginning from 1987, and from 1989 to 1999 we have followed hemoglobin values in elite cross-country skiers in international competitions. The mean values at the 1989 World Nordic Ski Championships were lower than population reference values, as would be expected from plasma volume expansion associated with endurance training. However, an increase, particularly in the maximal values, became obvious in 1994 and rose further in 1996. These extreme values provide both a health risk to the individual athlete and unfair competition. After a rule limiting hemoglobin values was introduced, the drop of the highest values was remarkable: among men 15 g/l (0.23 mmol/l) and among women 42 g/l (0.65 mmol/l). It would appear that the rule had achieved its goal of limiting extreme hemoglobin values. Yet the mean hemoglobin concentrations in men and women have continued to rise, suggesting the continued use of artificial methods to increase total hemoglobin mass.

Acclimatization↗
PubMed1995

Light concentric exercise and heavy eccentric muscle loading: effects on CK, MRI and markers of inflammation.

The consequences of a single bout of heavy eccentric exercise with and without repeated concentric exercises on MRI images, serum CK levels and markers of inflammation were studied. Two groups (ECC and ECCON), each consisting of 18 male volunteers, performed 70 eccentic contractions of the quadriceps femoris muscle. The study group (ECCON) performed additional concentric contractions on a dynamometer (Cybex II+) one day before and two hours, 1, 2, 3, 6 and 9 days after eccentric loading. Serum levels of creatine kinase (CK) were examined as a function of time, and correlated with measurements of magnetic resonance imaging (MRI) of the involved muscle groups. T2-weighted images of the thigh muscles were studied. Serum C-reactive protein, complement factors C3c and C4, haptoglobin and transferrin were measured as markers of inflammation. Additional concentric contractions (ECCON group) significantly increased CK, compared to the ECC group. However, it has no apparent effect on MRI signal intensity changes, which were of equal magnitude in the loaded vastus intermedius and deep parts of the vastus lateralis in both groups. Likewise, the serum markers of inflammation of the exercised muscles appeared to be absent. Based on MRI-images, additional concentric contractions had no statistically significant effect on muscle damage and breakdown of connective tissue. The five-fold increase in CK in the ECCON group could be a reflection of "massaging out" of the CK from the muscles into the circulation by additional concentric exercises. However, it could also be an indication for a superior sensitivity of assessing muscle fiber damage in comparison to the MRI.

Adult↗
PubMed1988

[Remarks on ECG changes during and following stress].

In order to obtain a relatively comprehensive picture of the functional capacity of the heart it is absolutely necessary to perform examinations under dynamic stress. The evaluation of an ECG during and immediately following ergometric stress presupposes a knowledge of the normal ECG pattern and also the characteristic pathological reactions. The ST changes and rhythm disturbances demand special attention. This article covers the most common normal and pathological patterns in addition to discussing several particular aspects of electrocardiograms taken during and after stress as well as their clinical importance.

Arrhythmias, Cardiac↗
PubMed1986

Beneficial effects of exercising at moderate altitude on red cell oxygen transport and on exercise performance.

The effect of a ascent to moderate altitude (2,300 m) and altitude training on the O2-transport properties of Hb and their possible consequences on tissue oxygenation during exercise were studied on six control and six training subjects. A rapid increase in P-50 values (+2.4 mm Hg, 0.32 kPa) was measured within one day after ascent. At the end of the stay at altitude (13th day) P-50 values were higher in subjects performing training than in controls. At altitude a slow but constant increase in 2,3-DPG, pyruvate kinase activity and reticulocyte count was found, which was more pronounced in training subjects as compared to controls. Ascent to altitude resulted in a decreased maximal performance capacity (-9%), but both groups recovered during the stay. In training subjects maximal exercise performance was increased after descent. Exercise at altitude was performed at a lower heart rate (controls: -10/min; training: -18/min) and at a lower lactate concentration (-4 mmol/l). These data indicate a positive effect of adaptation to altitude on exercise performance. Training itself shifts the ODC to the right and adds this effect to the effects of passive altitude adaptation on the O2-binding properties of hemoglobin.

Acclimatization↗
PubMed1981

[Influence of sport on the cardiovascular system in pregnancy (author's transl)].

Stroke volume and cardiac output were determined in 24 pregnant women at the end of the first and second trimenon. There was a decrease of cardiac output in 7 women (29%) and among these a decrease of stroke volume in 6 women (25%). In this group there were especially untrained women with a high incidence of "health complications" during pregnancy.

Adult↗
PubMed1981

[The significance of the self motion of the heart for the echo-cardiographic evaluation of the left ventricle].

The aim of the study was to analyse the motion of the heart with the two-dimensional echocardiography. With this method a swinging motion to the chest wall and to the apex at endsystole and early diastole in the long axis view could be observed. Moreover, in the short axis view a swinging motion in lateral direction in systole and a clockwise rotation at the level of the papillary muscles could be demonstrated. There were also changes of the beam direction during the respiration. Thus, a three dimensional motion not reflected by one dimensional echocardiography was considered. A given point of the ventricle wall, therefore, was not the same in systole and diastole, in spite of a continuously recorded structure in the m-mode. For this reason two dimensional echocardiography seems to be superior to one dimensional method, especially when systolic and diastolic parameters are compared. The entire motion of the heart has to be considered in one dimensional assessment of left ventricular function.

Coronary Disease↗
PubMed1977

[Myocardial performance during therapeutic starvation in obese subjects].

The effect was studied of therapeutic total starvation of two weeks' duration on myocardial performance in 12 obeses patients. Half of these subjects were trained for 10 minutes daily on a bicycle ergometer, whilst the other half had no training. After two weeks of total fasting no significant changes were observed either inter- or intracollectively with regard to systolic time intervals, ejection fraction and the index of myocardial contractility, nor in respect to serum electrolytes. Physical training had no influence on the systolic time intervals and the other noninvasive parameters of left ventricular performance. The inclusion of previous data obtained in a similar investigation enabled the establishment of a correlation between the serum potassium level and the ejection franction.

Adult↗
PubMed1976

[Lowering of pulmonary-arterial pressure with nitroprusside in mitral stenosis and cor pulmonale (author's transl)].

Nitroprusside was infused intravenously (20, 40, 80 and 200 mug/min) in nine patients with pulmonary hypertension due to mitral stenosis (group I), nine with precapillary pulmonary hypertension associated with primary lung disease (group II) and nine with normal pulmonary-arterial pressures (group III). The mean pulmonary-arterial pressure was markedly reduced at a rate of 20 mug/min in group I and II, while higher doses were necessary in group III to produce a similar effect. Mean arterial pressure was decreased in all three groups and was dose-related. Heart rate rose, stroke volume fell during nitroprusside administration, while cardiac output remained unchanged. Pulmonary vascular resistance was reduced on 20 mug/min in group I, but only on 200 mug/min or more in group II, and unchanged at all dosages in group III. Peripheral vascular resistance declined in all three groups on nitroprusside infusion, which is apparently of value in the short-term lowering of pulmonary hypertension.

Blood Pressure↗
PubMed1976

[Haemodynamics at rest and exercise capacity of patients treated by intermittent haemodialysis (author's transl)].

The haemodynamics at rest of 10 patients (mean age 42.6 years) with terminal renal failure treated by intermittent haemodialysis were studied over a period of 8 to 22 months by non-invasive methods. Additionally bicycle exercise testing was performed. After 13 months there was a reduction in cardiac index from 3.37 +/- 0.75 L/Min./m2 to 2.94 +/- 0.51 L/Min./m2 (p less than 0.05) and of the left ventricular minute work index from 6.21 +/- 1.60 mkp/Min./m2 to 5.71 +/- 1.36 mkp/Min./m2 (p less than 0.02). The blood pressure, index of peripheral resistance, systolic time intervals, arm-ear time and the ejection fraction showed no significant variations. Left ventricular failure was not detectable at rest, but the work capacity on exercise testing was reduced during the entire period of investigation without significant variation.

Adult↗
PubMed1976

The risk of injury in experienced Alpine skiers.

In 981 skiing accidents the type of injury resulting was studied in relation to the skiing activity (long distance, cross country, and downhill) and to the type of boots used. From the patterns of injuries it appears that in downhill skiing not only the velocity but also the particular type of equipment used is responsible for the increased incidence and for the characteristic type of injuries. The alpine ski boot used in downhill skiing, however, seems to protect the ankle joint and the foot from injuries that are more common in cross-country and long distance skiing.

Age Factors↗
PubMed1976

[Influence of atrial contraction on stroke volume in pacemaker stimulation].

The contribution of the atrial systole to the stroke volume was studied in 12 patients with implanted pacemakers by means of impedance-cardiography. P-ST-intervals between 70 and 200 msec. increased the stroke volume as compared with systoles without preceding P-waves. A maximal stroke volume was observed with a P-ST-interval of 130 msec. The increase of the stroke volume by 33% justifies the application of atrial triggered pacemakers in selected cases, mainly in younger patients despite of the technical limitations of these pacemaker systems.

Aged↗