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Giovanni Tanda,1 Beat Knechtle2,3 1Polytechnic School, University of Genoa, Genoa, Italy; 2Gesundheitszentrum St Gallen, St Gallen, 3Institute of Primary Care, University of Zurich, Zurich, Switzerland Background: Marathon (42 km) and 100 km ultramarathon races are increasing in popularity. The aim of the present study was to investigate the potential associations of anthropometric and training variables with performance in these long-distance running competitions. Methods: Training and anthropometric data from a large cohort of marathoners and 100 km ultramarathoners provided the basis of this work. Correlations between training and anthropometric indices of subjects and race performance were assessed using bivariate and multiple regression analyses. Results: A combination of volume and intensity in training was found to be suitable for prediction of marathon and 100 km ultramarathon race pace. The relative role played by these two variables was different, in that training volume was more important than training pace for the prediction of 100 km ultramarathon performance, while the opposite was found for marathon performance. Anthropometric characteristics in terms of body fat percentage negatively affected 42 km and 100 km race performance. However, when this factor was relatively low (ie, less than 15% body fat), the performance of 42 km and 100 km races could be predicted solely on the basis of training indices. Conclusion: Mean weekly training distance run and mean training pace were key predictor variables for both marathon and 100 km ultramarathon race performance. Predictive correlations for race performance are provided for runners with a relatively low body fat percentage. Keywords: running, performance, training indices, body fat, sports training

Giovanni Tanda,1 Beat Knechtle2,31DIME, Università degli Studi di Genova, Genova, Italy; 2Gesundheitszentrum St Gallen, St Gallen, Switzerland; 3Institute of General Practice and Health Services Research, University of Zurich, Zurich, SwitzerlandBackground: The purpose of this study was to investigate the effect of anthropometric characteristics and training indices on marathon race times in recreational male marathoners.Methods: Training and anthropometric characteristics were collected for a large cohort of recreational male runners (n = 126) participating in the Basel marathon in Switzerland between 2010 and 2011.Results: Among the parameters investigated, marathon performance time was found to be affected by mean running speed and the mean weekly distance run during the training period prior to the race and by body fat percentage. The effect of body fat percentage became significant as it exceeded a certain limiting value; for a relatively low body fat percentage, marathon performance time correlated only with training indices.Conclusion: Marathon race time may be predicted (r = 0.81) for recreational male runners by the following equation: marathon race time (minutes) = 11.03 + 98.46 exp(−0.0053 mean weekly training distance [km/week]) + 0.387 mean training pace (sec/km) + 0.1 exp(0.23 body fat percentage [%]). The marathon race time results were valid over a range of 165–266 minutes.Keywords: endurance, exercise, anthropometry

Analysis of the performance of various plate-fin heat exchangers reveals that the thermodynamic performance depends largely on operating conditions, such as heat transfer duty and mass flow rate. The performance of various plate-fin surfaces have been related to their reversibility level, while heat transfer and fluid flow exergy losses have also been taken into account. The analysis assumes that heat transfer duty, mass flow rate, and heat exchanger length and width remain fixed.

Freely moving rats were intravenously injected with cocaine, morphine and amphetamine in the nucleus accumbens shell and core at doses in the range of those known to sustain drug self-administration in rats. The effect of the drugs on dopamine levels were measured by microdialysis with vertically implanted concentric probes. Only the highest dose of amphetamine increased dopamine in both the shell and core. These results suggest that there is functional compartmentation within the nucleus accumbens for the effect of psychostimulants.

An analysis of the natural convection heat transfer properties of an array of four staggered vertical plates, and of the consequences of interplate spacing and the plate-to-ambient temperature, involved experiments conducted in air. Despite a 28% decrease in heat transfer area, with increases in relation to specific heat flux up to 30%, comparison of average heat transfer with a parallel plate channel with the same exchange size yielded only minor differences.

The natural convection of heat transfer from a wire and tube heat exchanger to ambient air may be expressed as a mathematical correlation, with the relationship being expressed as a Nusselt number. The most important geometric and operating parameters affecting this relationship include the spacing to diameter ratios of the tubes and wires, the height of the exchanger and the difference in temperature between the tube and the air.