## 1 Introduction  
Plantar heel pain is one of the most common musculoskeletal conditions affecting the foot in adults, with a highest incidence at the age of 40 to 60 years [1, 2]. There are many causes of pain in the plantar heel area, and one of them is due to a calcaneal/heel spur [3].  
A calcaneal spur is a condition where a calcium deposit grows between the heel and arch of the foot [4]. Generally, this does not affect a person's daily life, but repetitive stress from activities may result in the spur breaking into sharp pieces and pressing the nerves of the plantar fascia [5, 6, 7]. This condition causes plantar fasciitis, in which patients experience pain and tenderness at the heel [8, 9]. People who are obese, individuals with either flat feet or high arches, and individuals who engage in prolonged standing or walking are very vulnerable to this disease [6].  
Heel pain treatment (including pain caused by a calcaneal spur) is listed in the document of the Clinical Practice Guideline (CPG) developed by the heel pain committee of the American College of Foot and Ankle Surgeons (ACFAS), which recommends quick procedures in assessment and management of heel pain [10]. The authors classify treatments into three phases for heel pain treatments, and the use of orthotic shoes is recommended in phase II.  
Orthotic shoes for calcaneal spur patients are specially designed to reduce pain when used for walking activity by modifying pressure in the heel region [11; 12]. Pressure reduction using orthotic shoes requires knowledge of the location and dimensions of the spur, and typically the minimum pressure that causes pain in the patient's heel area. A large-dimension spur (\(\geq\)6 mm) causes high pain level compared to a small spur (1-2 mm) [13]. Determining the area in the heel where the spur growth is plays a major role in knowing the level of the pain. The research on pressure pain threshold (PPT) in patients experiencing plantar heel pain syndrome using a pressure algometer was presented by [PERSON] et al. [14]. To measure PPT, the heel was divided into five regions. The results indicated that PPT levels at posterior/medial, anterior/medial and central regions were significantly lower than at anterior/lateral and posterior/lateral regions.  
Various types of shoe soles have been studied to reduce pain in the heel area. Shoes with thick soles and extra cushioning can reduce pain while standing and walking [15; 16]. High-heel shoes can shift pressure away from the heel to the mid-foot and fore-foot [17]. Contoured insoles are better than flat insoles in reducing local peak pressures [18; 19; 20]. A number of methods have been carried out to estimate the contact pressures or pressure distribution patterns in both feet for each subject during standing and/or walking activity. The methods applied the finite element method (FEM) [15], used a pressure sensor, that is, the Force Sensing Resistor (FSR) [16; 17], were based on a weighting scale method [18], used a flexible F-Scan(r) insole sensing system [19], or used capacitance sensor/ transducers (the PEDAR(r) pressure measurement system) [20].  
Commonly, to obtain a contour-customized in-shoe foot orthotics is done by taking a plaster cast of the patient's foot plantar surface (the negative cast) and then moulding this negative cast on a plaster casting board to obtain the positive cast [21]. [PERSON] et al. [18] made the positive cast with full-weight-bearing and semi-weight-bearing by directly printing the plantar foot on the casting board placed on top of the electronic balance. Another method to obtain the patient's foot plantar surface is to use 3D scanning, which is the latest technology that has been widely used by many researchers [22; 23]. This study aims to determine the effect of contouring of an in-shoe foot orthosis on heel pressure while standing, and its relationship to the pain in the heel area.