[The effect of temazepam on the functional capacity and metabolic and cardiocirculatory parameters in consideration of the "jet lag" syndrome]. / Wirkung von Temazepam auf das Leistungsverhalten sowie metabolische und kardiozirkulatorische Grössen unter Berücksichtigung des "Jet lag"-Syndroms.

In a double-blind placebo controlled study, 14 male healthy volunteers were examined the morning after they had received an evening dose of 20 mg temazepam (Planum) with regard to functional capacity, cardial, cardiovascular and respiratory regulation as well as neuromuscular excitability and metabolic changes. After being exposed to the bicycle ergometer load, oxygen uptake, carbon dioxide output, glucose and lactate concentration were determined; furthermore the neuromuscular excitability of the musculus vastus medialis, musculus rectus femoris and musculus quadrizeps femoris was estimated. Despite unimportant capacity reductions (p greater than 0.05) concerning the maximum capacity (2.2%) as well as the maximum oxygen uptake (4.3%) under treatment with temazepam, there could not be proved any significant changes regarding cardiopulmonary and metabolic functions. On eastern and western flights, top athletes showed a very fast adaptation to the day-night rhythm without hang-over.

Decreased nocturnal catecholamine excretion: parameter for an overtraining syndrome in athletes?

The effectiveness of high performance training should be examined at short intervals in order to recognize overtraining promptly. Field or laboratory tests can usually not be performed with such frequency. Easy-to-measure biological, training-relevant parameters are being sought to use in their place. Since the importance of the sympathetic nervous system for adaptation of stress and the relationship between physical training and the activity of the sympathetic nervous system are well accepted, and since an impairment of the sympathetic nervous system is assumed in an overtraining syndrome, we examined the relevance of nocturnal "basal" urinary excretion of free catecholamines with respect to its practical application: 1. during a pilot study (training of road and track cyclists before the 1988 Olympic Games in Seoul), 2. through a 4-week prospective, experimental study in 1989 and 1990 (middle- and long-distance runners), 3. during the competitive season and winter break of a soccer team between August 1990 and April 1991. The following hypothesis was made: An overtraining or exhaustion syndrome in athletes may usually be accompanied by at least a 50% decrease in basal dopamine, noradrenaline and adrenaline excretion. When training is effective or the athletes are not exhausted, the decrease of the excretion rate--with the exception of dopamine--is more likely to be lower (noradrenaline, adrenaline). Generalization of these results requires further expansion of the experimental basis.

[Metabolic and cardiovascular adaptation and the performance of professional tennis players]. / Metabolische und kardiozirkulatorische Adaptation sowie Leistungsverhalten professioneller Tennisspieler.

14 professional tennis players of world rank were examined (7 men, mean age 23 +/- 3 years; 7 women, mean age 18 +/- 2 years). Heart volume (HV) was 11.9 +/- 0.9 ml/kg in women, 12.7 +/- 1.3 ml/kg in men, 20-30% higher than in untrained persons. Correspondingly, end-diastolic (EDV) and end-systolic volume, left-ventricular muscle mass (LVM) and stroke volume (SV) were elevated, while contractility parameters as well as the ratios of SV and of LVM to EDV and HV were within normal limits. The changes are to be taken as adaptations in the sense of athlete's heart. Maximal treadmill speed was 18 km/h in women and 19.3 km/h in men, with maximal lactate levels of 9.3 mmol/l (women) and 11.4 mmol/l (men). Anaerobic threshold was reached at a treadmill speed of 13.3 km/h (women) and 14.8 km/h (men). These data indicate a good performance range and were clearly better than in earlier groups of tennis players. This adaptation requires additional interval and endurance training. In 11 tennis players the serum concentration of magnesium and in 5 that of iron was below the recommended lower limit (magnesium: 0.8 mmol/l; iron: 14 mumols/l). Serum concentrations of creatine kinase and of lactate dehydrogenase were always two to three times higher than normal, if tennis training had taken place the day before, but all other biochemical values were within normal limits.

Stage duration and increase of work load in incremental testing on a cycle ergometer.

Any variation of the test protocol for incremental testing (IT) in cycle ergometry may affect the accuracy of the determination of anaerobic threshold (AnT). For lactate threshold concepts, indicating the maximum lactate steady-state (max Lass), the formation of the quasi-steady-state (QSS=95% of steady-state level) is evident. Previous studies have not specified the time that it takes for blood lactate to stabilize following incremental changes in WL. The purpose of this study was to identify the minimum duration of exercise necessary to establish QSS following various increments in WL (10, 20, 30, 40 and 50 W). Eight male endurance-trained cyclists [relative maximal oxygen consumption = 64.8 (4.2) ml x kg(-1) x min(-1)] performed three different exercise tests on a cycle ergometer: (1) an exhaustive IT with a starting WL of 100 W, followed by 20-W increments every 3 min; (2) a threshold test with 20-W increments every 9 min to determine the MaxLaSS; and (3) five incremental exercise tests (from 100/110 W, with 20-W increments every 3 min) with a final 10-, 20-, 30-, 40- or 50- W increment lasting 10 min, at 10 W below MaxLaSS (T10-T50 experiments). The time constant of lactate kinetics (tau), the time constant of lactate elimination, and the time taken to elicite QSS, defined as 95% of the time taken to reach steady-state level (t95%), were calculated in the T10-T50 experiments. The tau and t95% increased significantly with WL increment size: the correlation was not linear. Smaller WL increments required proportionally longer durations. Mean (SD) t95% values (min:s) were 1:57 (0:27) (T10), 2:58 (0.16) (T20), 4:08 (0:23) (T30), 4:45 (0:45) (T40) and 5:06 (0:43) (T50). The application of these references in IT protocols may lead to an extension of total test duration, particularly with smaller increments. Therefore, lactate threshold modelling, the training status of the athletes and comparability with lactate measurements obtained during training events should be considered. IT protocols not accomplishing QSS criteria may effect an underestimation of WL-related lactate values and an overestimation of lactate thresholds, which indicate MaxLaSS, especially in highly trained athletes. This suggests that the establishment of an increment-size-dependent t95% may reduce protocol-related influences on AnT and standardize the use of the AnT in IT procedures in the training management of elite cyclists.