# Foot Insole Pressure Distribution during the Golf Swing in Professionals and Amateur Players
## 4 Discussion
The maximum pressures are different in each foot according to [18], occurring in the lateral forefoot, heel, and hallux of the leading foot and  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**ST**} & \multicolumn{2}{c}{**MB**} & \multicolumn{2}{c}{**TB**} & \multicolumn{2}{c}{**IM***} & \multicolumn{2}{c}{**EF**} \\ \hline \multirow{5}{*}{**Difference Pro-Medium**} & **Areas** & **Mean** & \(p\) & **Mean** & \(p\) & **Mean** & \(p\) & **Mean** & \(p\) & **Mean** & \(p\) \\ \cline{2-10}  & TOES & 4\% & \(p<0.05\) & 0\% & \(p<0.05\) & \(-3\%\) & \(p>0.05\) & 4\% & \(p>0.05\) & 4\% & \(p>0.05\) \\  & METlat & 7\% (\({}^{*}\)) & \(p<0.05\) & 5\% & \(p>0.05\) & 1\% & \(p>0.05\) & 5\% & \(p>0.05\) & 8\% (\({}^{*}\)) & \(p<0.05\) \\  & METmel & 10\% (\({}^{*}\)) & \(p<0.01\) & 2\% & \(p>0.05\) & \(-1\%\) & \(p>0.05\) & \(-1\%\) & \(pin the medial forefoot and hallux of the rear. [PERSON] et al. [19], have also found that the behavior of the feet is different in relation with the insole pressures, showing a very similar information to ours, but without presenting statistical results. The most relevant conclusion of the former results is that plantar pressures agree with the classic principle of \"weight transfer\" from the rear foot to the lead [25]. This transfer in weight has been studied through reaction forces [6; 7; 8; 9], through the movement of the center of pressure in each foot [10; 11], or through the location of the total center of pressure [12; 13; 14]. In all cases, they argued the existence of a movement of the forces and the center of pressure towards the rear foot during the backswing, followed by a transfer towards the lead foot during the downswing. It should be mentioned that this is the so called \"standard\" pattern, but according to some authors there are players who opt for a so-called \"reverse\" pattern that shifts the weight towards the rear foot during the impact [12; 13]. However, our results only partially agree with the classic concept of weight transfer because we have shown that the transmission of loads is different and depends on the specific foot plantar area. We found out that in the lateral part of the foot (METlat, ARCIat, and HEELlat), the right foot is loaded before the left foot, while in the medial metatarsus and toes (METmed and TOES) the weight shift occurs in a reverse pattern, and the medial arch and medial heel (ARCmed and HEELmed) do not reveal any weight shifting between right and left feet. Further studies are needed to investigate whether this pressure transfer pattern (Figure 5) is unique or there are alternative patterns. Hypothesis # 2 is discarded. The pressures distributions are not different for the driver and the 5-iron. It is very important that this hypothesis is investigated for a proper swing training, since it means that the insole pressure distribution pattern in the swing is the same regardless of the applied club. Several authors have studied the foot pressure during the golf swing for a single club [15; 16; 18; 19], but we have not found any article comparing the foot pressure distribution using different clubs. Authors that used ground reaction forces to compare different clubs have shown that the generated forces by the driver (703 N) are higher than those produced by the 5-iron (695 N) [5], while the 3-iron and the 7-iron clubs have similar force values [10; 11]. From our point of view, it is an expected result that the absolute forces using the driver are higher than those using the irons, because the driver has higher moment of inertia (MOI), and thus requires more force to be moved. In our case, we have not observed differences between clubs, since the pressure has been normalized with respect to the total foot pressure, hence avoiding the effects of the club types and weight of players. In addition, other authors have recorded similar vertical torques in the driver than in the 3-iron and the 5-iron [21], as well as similar movement of the CoP using the driver, the 3-iron or the 5-iron [14].