## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Phase** & **Parameters** & **MI 26\%** & **MI 86\%** & **P** \\ \hline \multirow{3}{*}{Touch-down} & Knee flexion angle (\({}^{\circ}\)) & 12.64 \(\pm\) 4.56 & 13.56 \(\pm\) 5.60 & 0.637 \\  & Ankle plantar flexion angle (\({}^{\circ}\)) & 0.13 \(\pm\) 7.92 & 0.13 \(\pm\) 4.29 & 0.835 \\  & Foot inclination angle (\({}^{\circ}\)) & 12.54 \(\pm\) 2.18 & 8.07 \(\pm\) 4.64 & \textless{}0.001 \\ \hline \multirow{6}{*}{Stance phase} & FP (BW) & 1.74 \(\pm\) 0.23 & 1.78 \(\pm\) 0.16 & 0.701 \\  & SP (BW) & 2.59 \(\pm\) 0.31 & 2.61 \(\pm\) 0.25 & 0.559 \\ \cline{1-1}  & Peak knee flexion angle (\({}^{\circ}\)) & 36.29 \(\pm\) 3.41 & 33.93 \(\pm\) 1.74 & 0.008 \\ \cline{1-1}  & Peak patellofemoral joint contact area (mm\({}^{2}\)) & 280.10 \(\pm\) 21.96 & 265.08 \(\pm\) 10.20 & 0.008 \\ \cline{1-1}  & Peak knee extension moment (N \(\times\) m/kg) & 2.36 \(\pm\) 0.41 & 2.07 \(\pm\) 0.47 & \textless{}0.001 \\ \cline{1-1}  & Peak patellofemoral contact force (BW) & 5.23 \(\pm\) 1.12 & 4.34 \(\pm\) 0.97 & \textless{}0.001 \\ \cline{1-1}  & Peak patellofemoral contact stress (MPa) & 13.48 \(\pm\) 2.64 & 12.08 \(\pm\) 3.27 & 0.015 \\ \hline \hline \end{tabular}  
* Notes: Foot inclination angle is the angle between the foot and the ground. The FP (the first peak of the vGRF) and SP (the second peak of the vGRF), knee extension moment and patellofemoral contact force are standardised by body weight (BW). MI 86%: minimalist shoes. MI 26%: cushioned shoes.  
\end{table} 
Table 2: Sagittal plane kinematics and kinetics during running with two different shoe conditions (\(\overline{x}\pm\text{SD}\). -wearing minimalist shoes during the propulsive phase. This phase accounts for a large proportion and may be important for reducing the patellofemoral joint loads. Using the rating scale for minimalist shoes, this study compared minimalist shoes (MI = 86%) with cushioned shoes (MI = 26%) to further explore the relationship between knee joint load and the MI. [PERSON] [8] tested shoes with different MI with regards to running mechanics and observed that a higher MI shoe indicates a low foot inclination angle at foot strike and a low peak PFCF. [PERSON] [7] compared minimalist, cushioned and maximalist shoes in terms of patellofemoral kinetics and observed that the knee ROM decreased when the runner was wearing minimalist shoes. Interestingly, the patellofemoral joint loads were greater with the low-MI shoes, i.e., maximalist shoes, than with the others. The above findings are similar to the results of this study. Shoes with low MI caused no reduction in the patellofemoral joint loading despite the thick midsole. By contrast, the neural inputs caused by the cushioning midsole resulted in a reduced limb movement strategy with increased knee flexion angle and knee extension moment, which may increase the risk of knee joint load and PFPS. In previous studies, subjects were recruited regardless of their foot strike patterns and researchers failed to rule out runners who had experience with wearing minimalist shoes [13]. More than 70% of long-distance runners adopt the heel strike pattern [24; 25]. [PERSON] noted that heel strikers use the midfoot or forefoot strike pattern during the adaptation process when wearing minimalist shoes for the first time [26]. In the current study, the vGRF graph showed two peaks, and the foot inclination angle at the point of foot strike was positive. Therefore, the runners still used the heel strike pattern after wearing the minimalist shoes [27], but the foot inclination angle at the point of foot strike still reduced by 35.6%. Furthermore, adopting the heel strike pattern while wearing minimalist shoes on hard ground would cause heel pain. The runners who are used to rearfoot running have difficulties in switching to forefoot strike immediately when wearing minimalist shoes for a short distance.