# Foot Insole Pressure Distribution during the Golf Swing in Professionals and Amateur Players
## 1 Introduction  
The concept of weight transfer was first introduced as a popular term between players and coaches in an article in the Golf Digest magazine [1]. The weight transfer paradigm during the golf swing is a mechanical concept that golf coaches consider as an important metric for coaching the golf swing [2; 3; 4]. This concept has been intensively studied, mainly through variables obtained by means of a force platform, such as the distribution of the vertical force [5; 6; 7; 8; 9], the center of pressure [10; 11; 12; 13; 14], and the torque [7; 9]. However, a lack of information exists about the weigh transfer based on the pressure measured between the foot and the shoe [15; 16; 17]. [PERSON] and [PERSON] [12] has identified two styles of weight transfer based on the center of pressure (CoP) using cluster analysis: the \"Front Foot\" and the \"Reverse Pivot\" patterns. In the \"Front Foot\" pattern, players move the CoP backwards during the backswing and forward during the downswing phase. In the \"Reverse Pivot\" pattern, the CoP moves backwards during the backswing. However, after a short move forward, it moves again backwards and remains there during the downswing. On the other hand, [PERSON] [18], demonstrated that using only the center of pressure without considering the foot plantar distribution can be a limitation to properly understand the transmission of forces duringthe swing. [PERSON] et al. [16], have analyzed the foot pressure distribution during the swing using an instrumented foot pressure insole. They used an insole with three pressure sensors to collect data from 14 players separated into two handicap groups. They compared players, but they did not report any specific statistical pattern of the foot pressure distribution. [PERSON] et al. [19], analyzed the plantar pressure distribution in a sample of 18 players of different handicaps, but they compared only the maximum pressure without considering pressure variations during the whole swing. Another important issue is the relation between the support forces, plantar pressures, and the clubhead speed as a way of assessing the player performance. [PERSON] and [PERSON] [13], with a sample of different handicap players, indicated that a greater range and speed in the movement of the center of pressure during the downswing is associated with higher clubhead speeds in the \"Front foot\" pattern players. The same authors, [PERSON]. [20], with a sample of five players, observed that a greater CoP displacement is associated with a greater clubhead speed (\(p\) = 0.05). Other authors have obtained a relation of the amount of reaction forces [8] and vertical torques [7; 9] with the player's performance. [PERSON] [18], analyzed the relation between the plantar pressure and the clubhead speed. He measured golf swings of 32 players with handicaps between 2.7 and 25 and discovered that players with higher clubhead speeds also produce higher pressure values on the lateral side of the lead foot. Several authors have studied the relation between foot pressures and club type. For instance, [PERSON]. [5; 10; 11] have analyzed the weight transfer of the golfers using different clubs, and they have proved that reaction forces are bigger when players use the driver instead of the iron club; however, the vertical torques are similar [21]. [PERSON] and [PERSON] [14], concluded that the patterns of the CoP movement are similar when comparing golf swings with the driver and iron clubs. However, we have not found any information about the plantar pressures using different clubs. Reaction forces, vertical torques [21], and insole foot pressures [15; 19; 22] have been also used to compare different shoes. [PERSON] et al. [21], have analyzed the amount of vertical torque that exists between three types of shoes with different spikes and the natural grass surface in players of different levels. They observed that low handicap players generate more torque on the rear foot using the driver.