Critical Power in Laboratory and Field Conditions Using Single-visit Maximal Effort Trials.

To compare critical power (CP) and the maximum work performed above CP (W') obtained from a single-visit laboratory test with a single-visit field test, 10 trained cyclists (V˙O(2max) 63.2±5.5 mL·min(-1)·kg(-1)) performed a laboratory and a field test. The laboratory test consisted of 3 trials to exhaustion between 2-15 min and the field test comprised 3 maximal efforts of 2, 6 and 12 min, where power output was measured using a mobile power meter. CP and W' were estimated using 3 mathematical models (hyperbolic, linear work-time, linear power -1/time). The agreement between laboratory and field conditions was assessed with the 95% limits of agreement (LoA). CP was not significantly different between laboratory (280±33 W) and field conditions (281±28 W) (P=0.950). W' was significantly higher in laboratory (21.6±7.1 kJ) compared to field conditions (16.3±7.4 kJ) (P=0.013). The bias was -2.8±27 W (95% LoA: -55 to 50 W) and 6.4±5.1 kJ (95% LoA: -3.5 to 16.4 kJ) for CP and W', respectively. No differences between the mathematical models were found for CP and W' (P=0.054-1.000). Although CP was not significantly different between conditions, a high random variation does not support its interchangeable use. The mathematical model used has no influence on estimates of CP and W'.

Evaluation of a field test to assess performance in elite cyclists.

The study aimed to assess the reproducibility of power output during a 4 min (TT4) and a 20 min (TT20) time-trial and the relationship with performance markers obtained during a laboratory graded exercise test (GXT). Ventilatory and lactate thresholds during a GXT were measured in competitive male cyclists (n=15; (.)VO (2max) 67+/-5 ml x min (-1) x kg (-1); P (max) 440+/-38W). Two 4 min and 20 min time-trials were performed on flat roads. Power output was measured using a mobile power-meter (SRM). Strong intraclass-correlations for TT4 ( R=0.98; 95% CL: 0.92-0.99) and TT20 ( R=0.98; 95% CL: 0.95-0.99) were observed. TT4 showed a bias+/-random error of - 0.8+/-23W or - 0.2+/-5.5%. During TT20 the bias+/-random error was - 1.8+/-14W or 0.6+/-4.4%. Both time-trials were strongly correlated with performance measures from the GXT (p<0.001). Significant differences were observed between power output during TT4 and GXT measures (p<0.001). No significant differences were found between TT20 and power output at the second lactate-turn-point (LTP2) (p=0.98) and respiratory compensation point (RCP) (p=0.97). In conclusion, TT4 and TT20 mean power outputs are reliable predictors of aerobic endurance. TT20 was in agreement with power output at RCP and LTP2.

[Ethanol-independent methanol elimination in chronic alcoholics]. / Ethanolunabhängige Methanolelimination bei chronischen Alkoholikern.

72% of a collective of chronic alcoholics (DSM-III-R, ICD 9), who were admitted under the influence of alcohol in order to undergo alcohol withdrawal, showed a serum methanol concentration (SMC) above 10 mg/l. This level is usually considered to be the one for the detection of regular alcohol consumption. The SMC values were considerably higher in cases where alcoholic beverages with a higher methanol content were consumed rather than the ones lower in methanol. In the majority of patients a decrease of the methanol concentration could only be detected once an individually varying limit concentration of ethanol (0-0.62 g/kg) was reached. There were, however, a few exceptions where the elimination of methanol independent from the ethanol concentration could be seen. Contrasting the general collective, these 'ethanol independent' methanol eliminators showed a much higher serum level of ethanol and methanol at the time of admission. As a sign of addiction, all patients showed increased beta 60 values for ethanol and preferred high proof beverages, which at the same time have high methanol contents.