## 4 Discussion
This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research received no external funding. This research was not only in the last few years. Not applicable. Experimental data can be available for non-commercial purposes. Please contact: [EMAIL_ADDRESS]. The authors appreciate the collaboration of [PERSON] for his assistance during the tests. The authors declare no conflict of interest. Preliminary statistical hypothesis testing results about the influence of the headform size on the PLA or HIC variables. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Impact Point** & **Variable** & \
\begin{tabular}{c} **Headform** \\ **(E)** \\ \end{tabular} & **Headform (J)** &
\begin{tabular}{c} **Headform** \\ **(M)** \\ \end{tabular} & \(p\)-Value** \\ \hline \multirow{2}{*}{B point} & PLA (g) & 203 \(\pm\) 16 & 213 \(\pm\) 10 & 275 \(\pm\) 96 & 0.2367 \\ \cline{2-6}  & HIC & 1934 \(\pm\) 287 & 2091 \(\pm\) 251 & 2330 \(\pm\) 657 & 0.6889 \\ \hline \multirow{2}{*}{X point} & PLA (g) & 243 \(\pm\) 16 & 238 \(\pm\) 25 & 251 \(\pm\) 16 & 0.5538 \\ \cline{2-6}  & HIC & 2361 \(\pm\) 274 & 2132 \(\pm\) 330 & 2458 \(\pm\) 165 & 0.3039 \\ \hline \multirow{2}{*}{P point} & PLA (g) & 222 \(\pm\) 12 & 221 \(\pm\) 5 & 225 \(\pm\) 26 & 0.7859 \\ \cline{2-6}  & HIC & 2439 \(\pm\) 212 & 2259 \(\pm\) 127 & 2343 \(\pm\) 314 & 0.3166 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: PLA and HIC mean and SD for each headform group with the Kruskal–Wallis H test results (\(p\)-value) for each impact point tested at 8.2 m/s. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Helmet** & **Front** & **Top** & **Lateral Right** & **Lateral Left** & **Rear** & **Mean** & **SD** \\ \hline H1 & - & - & - & 4 & 10 & 7 & 4 \\ \hline H2 & - & 4 & 5 & - & 10 & 6 & 3 \\ \hline H3 & 11 & 4 & - & 10 & 7 & 8 & 3 \\ \hline H4 & - & 6 & 6 & - & 6 & 6 & 0 \\ \hline H5 & - & 18 & - & **25** & 11 & 18 & 7 \\ \hline H6 & - & 33 & 29 & - & - & 31 & 3 \\ \hline H7 & - & 14 & **23** & - & 16 & 18 & 5 \\ \hline H8 & 13 & 14 & **22** & - & - & 17 & 5 \\ \hline H9 & - & 13 & 27 & - & **30** & 23 & 9 \\ \hline H10 & 12 & 18 & - & 26 & - & 19 & 7 \\ \hline H11 & - & 14 & 13 & - & 10 & 12 & 2 \\ \hline H12 & - & 15 & 15 & - & 7 & 12 & 5 \\ \hline H13 & - & - & 10 & 10 & 15 & 12 & 3 \\ \hline H14 & - & 22 & - & 10 & 13 & 15 & 7 \\ \hline H15 & 6 & 10 & 9 & - & 17 & 10 & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Penetration test results: intrusion values by impacted area, mean, and standard deviation (SD) in millimeters for each helmet model. Intrusion values that failed the penetration test are shown in bold font.