# Selection of Posture for Time-Trial Cycling Events
## 3. Results  
### Characterization of Performance and Comfort Variables  
The results of the performance and comfort characterizations are summarized in Table 4. The drag area, rolling resistance coefficient, power delivery capacity, global average pressure, and vibration total value obtained for each rider are presented. It can be observed that for all the riders changing from ABh to ABl led to an improvement in the drag area (\(-10.7\%\pm 3.1\%\)), and deteriorations in the average power delivery capacity (\(-9.5\%\pm 5.4\%\)), pressure on the saddle (\(+16.5\%\pm 11.5\%\)), and vibrations on the saddle (\(+6.5\%\pm 4.0\%\)). Regarding the pressure and vibrations on the aerobars, changing from ABh to ABl led to different results for the different riders without a general tendency. The results of the variation of the drag area and power delivery capacity are in agreement with previous findings in which it is reported that, in trained male cyclists, lowering the torso angle leads to a significant reduction of physiological performance and aerodynamic gains [29]. The results of this study indicate that similar results could be obtained for female cyclists. The environmental conditions and heart rate registered during the characterization tests are presented in Table 5. It is worth highlighting that the air density and wind speed are variables that affect the estimation of the drag area and rolling resistance coefficient. For this reason, the methods used for their assessment include the estimation of air density and the measurement of wind speed. The air density was computed using the temperature, relative humidity, and atmospheric pressure registered in Table 5. The air density was found to lie in a small range for all of the tests (\(0.88\pm 0.01\) kg/m\({}^{3}\)). The wind speed varied between the testing days between headwinds of 12.9 m/s and tailwinds of 11.9 m/s, which emphasizes the relevance of including wind speed measurements for the estimation of this variable, as described by [PERSON] et al. (2017). Regarding the execution of the tests for the power delivery capacity characterization, it can be observed that the temperature and relative humidity were similar in all of the testing sessions (\(19.8\pm 0.9\)\({}^{\circ}\)C and \(59.0\pm 1.8\%\), respectively). These variables were registered to verify that the ambient conditions did not present a considerable variation between the tests of each rider to avoid possible effects of temperature and humidity on performance ([PERSON] et al., 2017; [PERSON] et al., 2017). It is also noted that the maximum and average heart rates of the cyclists were similar between the tests. The average heart rate difference between tests was \(2.4\pm 1.8\) bpm, reflecting that the cyclists had similar levels of effort in both tests. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Posture** & **Rider 1** & **Rider 2** & **Rider 3** & **Rider 4** & **Rider 5** \\ \hline \multirow{3}{*}{\(C_{D}A\) (m\({}^{2}\))} & ABh & 0.27 & 0.29 & 0.33 & 0.26 & 0.28 \\  & ABl & 0.23 & 0.26 & 0.31 & 0.23 & 0.25 \\ \multirow{3}{*}{\(f_{r}\) (-)} & ABh & 0.007 & 0.004 & 0.007 & 0.005 & 0.005 \\  & ABl & 0.007 & 0.004 & 0.007 & 0.005 & 0.005 \\ \multirow{3}{*}{\(P_{1h}\) (W)} & ABh & 180 & 233 & 179 & 228 & 161 \\  & ABl & 168 & 193 & 169 & 217 & 140 \\ \multirow{3}{*}{\(p_{S}\) (kPa)} & ABh & 52.2 & 26.1 & 15.8 & 39.0 & 13.9 \\  & ABl & 58.5 & 28.1 & 20.9 & 48.6 & 14.7 \\ \multirow{3}{*}{\(p_{AB}\) (kPa)} & ABh & 28.9 & 31.8 & 25.1 & 29.8 & 19.5 \\  & ABl & 31.5 & 35.8 & 23.4 & 25.9 & 22.0 \\ \multirow{3}{*}{\(a_{eS}\) (m/s\({}^{2}\))} & ABh & 2.56 & 2.74 & 3.04 & 2.95 & 3.00 \\  & ABl & 2.90 & 2.88 & 3.13 & 3.15 & 3.13 \\ \multirow{3}{*}{\(a_{vAB}\) (m/s\({}^{2}\))} & ABh & 4.24 & 5.54 & 4.91 & 4.62 & 4.32 \\ \cline{1-1}  & ABl & 4.37 & 4.59 & 4.45 & 4.71 & 4.42 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Performance and comfort indices obtained from characterization.