# The Contribution of Ski Poles to Aerodynamic Drag in Alpine Skiing
## 4 Discussion  
The major findings from this investigation on the contribution of the ski poles to total aerodynamic drag during alpine skiing were as follows: (i) the average cross-sectional area of the ski poles (\(\mathrm{S_{p}}\)) ranged from 0.0067 in the tuck position to 0.0262 m\({}^{2}\) in the middle position; (ii) these areas accounted for 2.2-4.8% of the total cross-sectional area; (iii) the contribution of the ski poles to the total cross-sectional area was dependent on wind speed in the high and middle positions; (iv) at 80 km/h, the inter-subject variations in this contribution ranged from 0.0018 m\({}^{2}\) (27.6%) in the tuck position to 0.0072 m\({}^{2}\) (30.5%) in the high position; and, finally, (v) \(\mathrm{S_{p}}\) exerted a likely effect on the coefficient of drag (\(\mathrm{C_{d}}\)) and \(\mathrm{C_{d}}\)-S (product of coefficient of drag and total cross-sectional area). This study involved 10 elite skiers who assumed three different standard positions five times at each of three different wind speeds in a wind tunnel. We did not standardize these conditions, as was done in certain previous studies [8; 13; 15], because the variations in the positions of the skiers and their poles, as well as in the wind speed, allowed us to examine the influence of these different conditions on the impact of the poles of aerodynamic drag. Moreover, the posture of a skier during a race varies considerably, often deviating from the basic positions, as he/she adapts to the varying terrain, snow conditions, and gate positions [23]. Our current findings reveal that the \(\mathrm{S_{p}}\) could account for as much as 5.0 \(\pm\) 0.8% of the total frontal cross-sectional area (Table 1), making the greatest absolute contribution in the high position and the most pronounced relative contribution in the middle position. Furthermore, the intra-skier variations in \(\mathrm{S_{p}}\) were relatively extensive (17.1-34.8%), more so apparently at the two highest speeds examined. This variation for all of the skiers combined was even more pronounced (35.6-63.0%), as were the absolute differences between skiers (Figure 2). Knowing that aerodynamic drag is one of the two resistive forces in alpine skiing [4; 7; 24; 25] contributing to energy dissipation [6; 26], these observations indicate that the ski poles may be responsible for variations in total energy loss as great as 1% (considering that maximally 28% of the energy loss during giant slalom is due to aerodynamic drag [[PERSON] et al., 2013][6], a 5.8% relative cross-sectional area of the poles, and 63% variation), with an average of approximately 0.3% (considering that, on average, 15% of the energy  
Figure 4: The values of \(\mathrm{C_{d}}\) (coefficient of drag) and \(\mathrm{C_{d}}\)-S (product of coefficient of drag and total cross-sectional area) are predicted by the cross-sectional areas of the ski poles (\(\mathrm{S_{p}}\)). Gray shaded areas represent a 95% confidence interval. loss during giant slalom is due to aerodynamic drag ([PERSON] et al., 2013) [6], a 4.5% relative cross-sectional area of the poles and 40% variation (the latter two values being approximately the mean values for the middle and high positions). No more than a fraction of a second often separates the finishing times of the gold and silver medallists [12], e.g., 0.01 s or 0.015% in the case of the Super Giant Slalom for men in the recent 2023 Alpine Skiing World Championships. As illustrated in Figure 3, the position in which the skiers held their poles varied considerably, which, since there is an obvious geometrical relationship between the cross-sectional area and inclination of the poles in the airstream, influenced the values of the cross-sectional area obtained. It should be noted that in the example shown in this figure the S\({}_{\text{p}}\) for the poles declined with increasing wind speed, whereas the graph in Figure 2 shows that the opposite was more often observed for this particular Skier 8.