## 2 Materials and Methods  
Thirteen patients (3 male and 10 female) at the local public hospital Tugurejo Semarang with plantar heel pain due to a calcaneal spur from June 2017 to August 2018 were involved in the experimental work of the study. The ethical clearance has been approved and issued by the Ethics Committee of the Tugurejo Hospital. All subjects have also signed and provided their written informed consent before participating in this study. The diagnosis of plantar heel pain of the patients was based on pain upon palpation. The mean age of the subjects was 56.5 \(\pm\) 9.9 years (range between 38-73 years), mean height was 155.6 \(\pm\) 7.6 cm (range from 144 to 172 cm) and mean weight was 63.3 \(\pm\) 9.4 kg (range between 50-84.6 kg). The location and dimension of each patient's spur were obtained from lateral X-rays [17]. The length of the spur is classified into 3 types: small (1-2 mm), medium (3-5 mm) and large (\(\geq\)6 mm) [13]. There were 7 patients with a calcaneal spur on both feet, but in this study, only the longest spur was evaluated because there is a significant correlation between the length of spur and the pain minimum compressive pressure (PMCP) [17].  
In order to obtain an exact location and dimension of the spur in the plantar view as shown in Figure 1 up, each patient was requested to do a two-dimensional footprint using a digital footprint scanner (LSR 2D Laser Foot Scanner, Vismach Technology Ltd., China). This scanner is equipped with software to measure foot length (FL) and foot width (FW) to determine the shoe size and heel width (HW) of each patient [24]. The spur is assumed to be located in the heel center line, which is a line drawn from the center of the heel (CH) to the tip of the second toe [25].  
The pain in the heel area was measured using an FDIX 25 algometer (Wagner Instruments, Greenwich CT, USA), which consists of a flat rubber tip probe 1.0 cm in diameter [26]. This instrument can display the compression force in either Newtons or kilograms and also can measure the pressure which is calculated from the force divided by the probe area. The region of the pain pressure threshold (PPT) was determined around the spur growth which is divided into five points: point 1 at the base of the spur, and the next compressive test points at the anterior site (point 2), the lateral site (point 3), the posterior site (point 4), and the medial site (point 5), made circular with radius of spur length, L plus 1 cm as presented in Figure 1 down. The addition of 1 cm is needed to compensate for the diameter of the algometer probe. The calculation method of PPT region in this paper is similar to the study conducted by [PERSON] et al., but the exact location of pain suppression was not specified and the patients recruited were not specifically recruited due to the calcaneal spur [14].  
To measure PPT, the patient was requested to lay supine in a relaxed position and press the algometer probe at point 1 as shown in Figure 1 down. S is the distance from the tip of the heel to the base of the spur and L is the length of the spur. We increased the pressure gradually until the patient complained of pain. We recorded the pressure value and applied a similar procedure to others points. From the recorded data, the PMCP and the point location in each patient can be monitored [17].