Abstract
Aim Ski-mountaineering contains elements from the alpine ski and cross-country ski. An increase number of ski-mountaineers around the world is documented, but the research in the area remains still limited.
Energetic and biomechanics aspect of ground human locomotion have been widely studied by researchers. Walking, running, and cycling are largely characterized in their different aspect.
The goal of the present study is to assess the effect of the speed and the slope on the energy expenditure during ski-mountaineering. Methods Twelve athletes (mean age 30 +- 8 years) took part in the study.
The energy expenditure was determined by spiroergometry based on the ratio of O2 and CO2 exhaled. The anthropometric values and individual ventilation parameters was measured and followed individual warming up.
The study was undertaken on the treadmill (Saturn HP Cosmos, Germany) allowing to walk with specially adapted roller skis and poles modified for ski-mountaineering. The test was initiated by a warm-up lasting for 4 minutes at a speed of 3.5 km.h-1 and 16% slope.
The next measurements consisted of 4 parts: walking at 24% gradient and speed 3.5 km.h-1, 20% gradient and speed 4.2 km.h-1, 16% gradient and speed 5.1 km.h-1 and 12% slope with a speed 6.8 km.h-1. The load lasted for 8 minutes 30 seconds in order to achieve the elevation 200 m.
The passive recovery for 20 minutes was administered between each measurement. Results The average energy expenditure at 24% slope was 273.4 +- 57.1 kJ, at a 20% slope 280.8 +- 7.7 kJ, at a 16% slope 300.1 +- 62.3 kJ and at a 12% slope 324.8 +- 44.3 kJ.
The results showed the lowest energy expenditure at 24% gradient and speed 3.5 km h-1. Conclusion During sport events, competitors often try to go up in the steepest slope.
Our study confirmed this behavior, as the lowest energy expenditure was achieved at the 24% slope. The lowest energy expenditure was shown during the walking on skis in steepest slope and lowest speed of locomotion.