Snow Temperature Change During Cross-Country Skiing At Moving Thermography Images
Vol.4,No.2(2010)
Twenty years ago, it was shown that friction increases the temperature of snow skis. Temperature changes permit the glide of the skis. The aim of this pilot study was to determine whether dynamic infrared thermography is able to capture rapid changes in the temperature of snow in all areas (not just at one point), on the ski tracks before and after passing. The snow was monitored on the track after 60 races; two runners in various weights (86 and 73 kg) on two types of skis and lubrication (for classic and skating cross) and at three different speeds (3,04±0,180, 3,81±0,273 a 5,30±0,314 m.s-1). Measurements of infrared radiation and the calculation of snow surface temperature immediately before and after a passing skier was carried out thermo-graphic system FLIR SC620 with 30 Mhz. Nonparametric Wilcoxon test for paired comparison of values found significant increases in temperature after the snow cleared the skies: runner A from -3,71 to -3,50 °C (p=0,000000) and runner B from -3,75 na -3,50 °C (p=0,000000). The return to baseline temperature was within 5 seconds after passing. Differences were demonstrated in the temperature of snow between runners with different masses and the use of different types of skis. The study confirmed the ability of dynamic infrared thermography to register very rapid temperature changes of snow in an area immediately before and after cross-country skiers passed. Dimensional dynamic thermography would seem to contribute to the choice of the correct strategy and lubrication in ski racing. However, it is necessary to make a series of validation studies.
snow temperature; cross country skiing; infrared thermography
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