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Biomedical subjects

B Weiler

Publications and source records attributed to B Weiler.

8 recordsLinked to original sources
PubMed1998

Ergometric and psychological findings during overtraining: a long-term follow-up study in endurance athletes.

In the present prospective longitudinal study 17 male endurance trained athletes (cyclists and triathletes; age 23.4+/-6.7 years, VO2max 61.2+/-7.5 ml x min(-1) x kg(-1); means+/-SD) were investigated both during a state of overtraining syndrome (OT: N=15), mainly induced by an increase of exercise intensity, as well as several times in a state of regular physical ability (NS: N=62). Cycle-ergometric and psychological data were compared for a period of approximately 19 months. On 2 separate days, each subject performed a maximum incremental graded exercise, two anaerobic tests (10 s and 30 s) as well as a short-endurance "stress test" with the intensity of 110% of the individual anaerobic threshold until volitional exhaustion. The mood state was recorded by a psychological questionnaire including 40 basic items. During OT the submaximal lactate concentrations were slightly decreased. The performance of the 10 s- and 30 s-tests was unaffected. In contrast, the duration of the "stress test" decreased significantly by approximately 27% during OT compared to the individual NS. The submaximal oxygen uptake measured during the incremental graded exercise was slightly higher during OT as compared to NS, whereas the submaximal and maximal respiratory exchange ratio, maximal heart rate and maximal lactate concentrations were decreased. At the 10th minute of the "stress test", ammonia tended to be increased during OT (P=0.048). The parameters of mood state at rest as well as the subjective rating of perceived exertion during exercise were significantly impaired during OT. In conclusion, the results indicate a decreased intramuscular utilization of carbohydrates with diminished maximal anaerobic lactacid energy supply during OT. Neither the lactate-performance relationship during incremental graded exercise nor the anaerobic alactacid performance showed alterations. The duration of the short-endurance "stress test", the maximal lactate concentration of the incremental graded exercise as well as the altered mood profile turned out to be the most sensitive parameters for the diagnosis of OT.

Adult↗
PubMed1994

Plasma catecholamines during endurance exercise of different intensities as related to the individual anaerobic threshold.

The study investigated the concentrations of free plasma catecholamines (CAT), adrenaline and noradrenaline, in comparison to heart rate and lactic acid concentrations during endurance exercises (EE) of different intensities related to the individual anaerobic threshold (IAT). A group of 14 endurance trained male athletes took part in the tests on a treadmill. After an exhausting incremental graded test (increasing 0.5 m.s-1 every 3 min) to determine the IAT, the subjects performed EE of 45 min in randomized order with intensities of 85%, 95%, 100% and 105% (E85-E105) of the IAT. The heart rate and CAT increased continuously during all EE. The CAT reacted sensitively to EE above IAT (E105) and showed an overproportional increase in comparison to EE performed with an intensity at or below IAT. At the same time, at exercise intensities up to IAT (E85-E100) a lactate steady state was observed whereas mean lactate concentrations increased during E105. The changes of lactate concentration allowed a better differentiation between E85-E100 as CAT measurements. In E95, E100 and E105 there was a partial overlap of heart rate, which in contrast to lactate concentration only differed by about 5%, so that small variations in heart rate could have coincided with considerable differences of exercise intensity when working at intensities near or above IAT. It was concluded that the range of IAT seemed to represent a real physiological breakpoint which corresponded to the aerobic-anaerobic transition.

Adult↗
PubMed1993

Circulating leucocyte subpopulations in sedentary subjects following graded maximal exercise with hypoxia.

Ten healthy sedentary subjects [age, 27.5 (SD 3.5) years; height, 180 (SD 5) cm; mass, 69.3 (SD 6.3) kg] performed two periods of maximal incremental graded cycle ergometer exercise in a supine position. Randomly ordered and using an open spirometric system, one exercise was carried out during normoxia [maximal oxygen consumption (VO2max) = 38.6 (SD 3.5) ml.min-1.kg-1; maximal blood lactate concentration, 9.86 (SD 1.85) mmol.l-1; test duration, 22.6 (SD 2.7) min], the other during hypoxia [VO2max = 33.2 (SD 3.2) ml.min-1.kg-1; maximal blood lactate concentration, 10.38 (SD 2.02) mmol.l-1; test duration, 19.7 (SD 2.8) min]. At rest, immediately (0 p) and 60 min (60 p) after exercise, counts of leucocyte subpopulations (flow cytometry), cortisol and catecholamine concentrations were determined. At 0 p in contrast to normoxia, during hypoxia there was no significant increase of granulocytes. There were no significant differences between normoxia and hypoxia in the increases from rest to 0 p in counts of monocytes, total lymphocytes and lymphocyte subpopulations [clusters of differentiation (CD), CD3+, CD4+CD45RO-, CD4+CD45RO+, CD8+CD45RO-, CD8+CD45RO+, CD3+HLA-DR+, CD3-CD16/CD56+, CD3+CD16/CD56+, CD19+] as well as adrenaline, noradrenaline and cortisol concentrations. The counts of CD3-CD16/CD56(+)- and CD8+CD45RO(+)-cells increased most. At 60 p, CD3-CD16/CD56+ and CD3+CD16/CD56(+)-cell counts were below pre-exercise levels and under hypoxia slightly but significantly lower than under normoxia. We concluded that the exercise-induced mobilization and redistribution of most leucocyte and lymphocyte subpopulations were unimpaired under acute hypoxia at sea level. Reduced increases of granulocyte counts during the study and reduced cell numbers of natural killer cells and cytotoxic, not major histocompatibility complex-restricted T-cells, only indicated marginal effects on the immune system.

Adult↗
PubMed1993

Individual anaerobic threshold and maximum lactate steady state.

The individual anaerobic threshold (IAT) as defined by Stegmann et al. 1981 is determined by using the blood lactate-performance relationship during incremental graded exercise and the immediately following recovery phase. The aim of the study was to investigate the validity of the IAT as a measure for the maximum lactate steady state (max Lass) and the monitoring of endurance training. Sixteen endurance trained athletes (VO2max 60.2 +/- 5.0 ml.min-1 x kg-1) performed a stepwise increasing test until exhaustion on a cycle ergometer (CE) (increasing by 50 W every 3 min), 14 endurance trained athletes (VO2max 64.9 +/- 3.8 ml.min-1 x kg-1) performed the multistage steptest on a treadmill (TM) (increasing by 0.5 m.s-1 every 3 min) to determine the IAT and the 4 mmol.l-1 La-threshold (AT). Afterwards endurance tests (E) limited to 30 min (CE) or 45 min (TM) were performed with intensities of 85, 95, 100 and 105% of the IAT (E85-E105) and with 100% of the AT (AT100) (only on CE) in a randomized order each on different days. Lass was present without premature break-off during E85 (in 30 out of 30 cases), E95 (30/30 cases) and E100 (26/30 cases). At E105 and AT100 (104 +/- 7% of IAT) mean La increased continuously and/or led to a premature break-off (in 15/30 cases). All subjects with an AT below their IAT were in Lass during AT100.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Heart rate, blood lactate, and catecholamines during ergometer and on water rowing.

The heart rate, blood lactate, and catecholamine responses to rowing on a Gjessing ergometer and in a single scull on the water were compared. Seventeen rowers performed a multistage step test on the ergometer as well as low and high intensity endurance rowing on the water. Seven oarsmen (six with determinations of free plasma adrenaline and noradrenaline) rowed on the ergometer with the same heart rate and duration as on the water. During ergometer endurance rowing, heart rate, lactate, and adrenaline were not significantly different from boat rowing, while plasma noradrenaline was higher. However, at similar lactate levels, heart rate during rowing on the water was approximately 10 beats.min-1 higher than during the ergometer multistage step test, due to the different duration of exercise. Heart rate values based on determination of lactate threshold can be taken as recommendations for low and high intensity endurance training on water. However, because of individual variations in the heart rate-lactate relationship between rowing on the ergometer and in the boat, field evaluation is recommended.

Adult↗
PubMedDate not supplied

Self-concept, marital vulnerability and brain damage.

The present study investigated the influence of a man's brain injury on both his and his wife's self-concept and perception of marital vulnerability. Thirty-six couples in which the husbands had brain damage and twenty-nine couples without disability filled out the Tennessee Self-concept Scale [1], and the Marital Vulnerability Scale [2]. Marital vulnerability of husbands with brain damage was found not to differ from that of the husbands in the control group. However, the marital vulnerability of the wives of the former husbands was lower than that of the other wives. Both men with brain damage and their wives exhibited a decrease in self-esteem and an increase in conflict and pathology. Brain damage appears to affect both the extent and direction of the relations between aspects of the self-concept and marital vulnerability differentially for husbands with brain damage and their wives. Practical and theoretical implications of the negative impact of brain damage upon the person with the damage, upon his wife, and upon their marital relationship are discussed.

Adaptation, Psychological↗