# The Impact of Skinsuit Zigzag Tape Turbulators on Speed Skating Performance
## 5 The Impact of the Zigzag Strips on Skating Performance in a Real Skating Environment
### Looking Closer at the 1998 Nagano Results
The risk temperature and the ice friction coefficients may have differed from the assumptions, but by far not to the degree that it covers the missing power of 21 Watts. For a matching power, the risk temperature in Heerenveen should have been 29 \({}^{\circ}\)C, or the ice friction coefficient in Calgary should have been 42% higher compared to Thialf. Considering the fact that at both occasions a world record was skated, the circumstances will have been quite optimal for both well-known ice rinks. This power dissimilitude at sea level and altitude was already addressed by [PERSON] in the early nineties of the last century [18]. More recently, [PERSON] et al. [19] showed that a reduction in gross efficiency of athletes is connected to the lower power output at altitude. The fact that the existing world records in speed skating have been accomplished at the higher elevation rinks of Calgary and Salt Lake City shows that despite the lower power output the lower density at altitude prevails. Studying speed-skating competition performance data in a complete Olympic season in the years 2010-2011 to 2013-2014, [PERSON] et al. [20] found a mean performance improvement of 2.1% per 1000 m altitude increase for senior skaters, all distances combined. [PERSON] [21] analyzed the 1000 m sprint during the World Cup competition in the season 2007-2008 and reported a 2.6% faster speed at altitude (combined Calgary and Salt Lake City results). However, also much lower speed improvements occur. Comparison of the 5000 m speeds of the top 12 elite skaters during the World Cup and the World Championship Single Distances in the season 2019-2020 give over speed values of only 1.1% for Calgary and 1.4% for Salt Lake City, compared to the two races in Heerenveen at sea level. In the study of [PERSON] et al. [19], 21 trained male cyclists were tested at sea level and at 1500 and 2500 m simulated altitude. Participants were instructed to perform a time trial of 4000 m and to complete it as fast as possible, giving average power output values of 317 (\(\pm\)26)W at sea level, 286 (\(\pm\)32)W at 1500 m and 255 (\(\pm\)23)W at 2500 m. In terms of exertion, this seems to come closest to completing a 5000 m race in speed skating. Figure 9 presents the linear regression on these points. This line was used to define a percentage of athlete power loss with altitude. For 1000 m altitude, this factor is 0.923. In addition, for the present calculations, a correction was made on elevation. Instead of the rink altitude, a corrected elevation based on the International Standard Atmosphere (ISA) was used, fitting the actual local barometric pressure. Using this model, the power spent by [PERSON] in Nagano and Calgary was determined (Table 4). Note that the local barometric pressure in the Nagano M-wave at the day of the race was extremely low for its elevation of 342 m. With the calculated available power, the resulting drag areas in Nagano and Calgary were determined, showing improvements of 5.3% and 4.2%, respectively. For sea-level conditions, a 5.3% reduction in drag points occurred at a lap-time improvement of 0.54 s on the 5000 m. \begin{table}
\begin{tabular}{l c c c c c c c c c} \hline
**Location** & **T (\({}^{\circ}\)C)** & **Pbar (hPa)** & **\(\rho\) (kg/m\({}^{3}\))** & **h-cor (m)** & **Loss Factor (-)** & **P (W)** & **V\({}_{\text{avg}}\) (m/s)** & **C\({}_{\text{D}}\)A** & **Improvement (\%)** \\ \hline Heerenveen & 13 & 1012 & 1.232 & 0 & 0 & 397.9 & 12.800 & 0.2750 & 0 \\ Nagano & 13 & 951 & 1.158 & 540 & 0.958 & 381.2 & 13.082 & 0.2605 & 5.27 \\ Calgary & 13 & 890 & 1.084 & 1080 & 0.917 & 364.9 & 13.107 & 0.2634 & 4.22 \\ \hline \end{tabular}
\end{table} 
Table 4: The calculated drag area of [PERSON] in Nagano and Calgary with his estimated power available at altitude, using a power loss factor of 0.923 per 1000 m elevation. Local barometric pressures were used; h-cor is the corrected elevation according to the ISA standard.