J. Hum. Ergol., 44: 11-20, 2015
COMPARING 3D FOOT SHAPE MODELS BETWEEN TAIWANESE AND JAPANESE FEMALES
YU-CHI LEE1, MAKIKO KOUCHI2, MASAAKI MOCHIMARU1 AND MAO-JIUN WANG1*
Department of Industrial Engineering and Engineering Management, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan *E-mail:
[email protected] 2 Digital Human Research Center, National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi, Koto-ku, Tokyo 135-0064, Japan. 1
ABSTRACT This study compares foot shape and foot dimensions between Taiwanese and Japanese females. One hundred Taiwanese and 100 Japanese female 3D foot scanning data were used for comparison. To avoid the allometry effect, data from 23 Taiwanese and 19 Japanese with foot length between 233 to 237 mm were used for shape comparison. Homologous models created for the right feet of the 42 subjects were analyzed by Multidimensional Scaling. The results showed that there were significant differences in the forefoot shape between the two groups, and Taiwanese females had slightly wider feet with straighter big toe than Japanese females. The results of body and foot dimension comparison indicated that Taiwanese females were taller, heavier and had larger feet than Japanese females, while Japanese females had significantly larger toe 1 angle. Since some Taiwanese shoemakers adopt the Japanese shoe sizing system for making shoes, appropriateness of the shoe sizing system was also discussed. The present results provide very useful information for improving shoe last design and footwear fit for Taiwanese females. Key words: Homologous modelling; foot anthropometry; ethnic differences; shoe sizing INTRODUCTION
Human feet have complicated anatomical structure and geometric features. Different ethnic groups tend to have different foot shape characteristics. Previous studies applied some foot feature variables to classify foot shape types (Kouchi, 1995; Mochimaru et al., 2000; Nilsson et al., 2012; Rodrigo et al., 2012). Krauss et al. (2008) classified European feet into three types including voluminous, flat and slender. Luo et al. (2009) reported that American females had narrow and high arches and American males had broad and low arch foot shapes. Hong et al. (2011) found that among the Chinese people, short feet tended to be associated with voluminous feet, and narrow and flat feet tended to be associated with long feet. These studies reported special findings in foot characteristics based on their own foot anthropometric data and provided useful information for footwear design (Sun et al., 2009). For global footwear manufacturing and marketing, it is important to understand the ethnic differences in foot shape and take these differences into consideration in footwear design and production. Hawes et al. (1994) compared the two-dimensional forefoot shape differences between different ethnic groups using a database of 708 American and 513 Asian (Japanese and Korean) male subjects. They found that the Asian male’s feet had a less acute angle in the long axis than that of the North American and the difference in forefoot shape was due to foot breadth difference. Kusumoto et al. (1996) compared the ethnic differences in foot morphology between Filipino and Japanese females. They found a significant difference in the toe 1 angle between the two groups. Gonda and Katayama (2006) reported that the Tongans had significantly longer and wider feet than the Japanese, French, Australian Aborigines and West Africans. Received 20 February 2015; accepted 12 June 2015
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More recently, Lee and Wang (2014) classified the Taiwanese female’s feet into three foot types including NL (narrow foot with low arch height), SH (short instep length, with high arch height) and LW (long instep length with wider foot and average arch height) types and indicated that instep length, foot breadth and arch height were the three principal foot dimensions for classifying Taiwanese female foot shapes. In real world practice, some Taiwanese shoemakers used the Japanese shoe sizing system (JIS S5037, 1998) as a basic reference, and made some modifications based on their own experiences. It seems that there is a lack of information about the foot shape differences between the two groups. Using the shoe last design with inadequate shape and an inadequate sizing system may lead to a poor fitting problem. Hence, this study aims to compare foot shape between Taiwanese and Japanese females by analyzing 3D foot homologous models and provide some specific information to the practitioners. METHODS
Subjects Three dimensional foot scanning data of 100 Taiwanese females and 100 Japanese females were randomly sampled from the foot database of 1000 Taiwanese and 410 Japanese. The Taiwanese data were collected in the Digital Ergonomics Laboratory, National Tsing Hua University, Taiwan. The Japanese data were collected in the Digital Human Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Japan. None of the subjects had any history of visible foot abnormalities or foot illnesses. The 3D scanning data were collected from February 2011 to June 2012. The protocol for Taiwanese data collection was approved by the Institutional Ethics Committee of National Tsing Hua University. The Japanese experimental protocol was reviewed and approved by an Institutional Ethics Committee of AIST. The basic demographic data and foot dimensions of the Taiwanese and Japanese female subjects are presented in Table 1. The average age was 22.2 years for the Taiwanese females and 23.7 years for the Japanese females. The mean height and weight was 1612.4 mm and 52.0 kg for the Taiwanese females, and was 1579.3 mm and 49.2 kg for the Japanese females, respectively. Table 1. The means and standard deviations of the body dimensions of the Japanese and Taiwanese females and the t-test results. ID Measurement item Age (year) Stature (mm)
Japanese (n=100) 23.7±3.1
Taiwanese (n=100) 22.2±2.9
1579.3±48.3 1612.4±52.1
Difference† t-test 1.5
***
-33.1
***
Weight (kg)
49.2±4.4
52.0±6.4
-2.8
**
BMI (kg/m2)
19.7±1.6
20.0±2.3
-0.27
n.s.
1 Foot length (mm)
230.2±8.6
235.3±10.2
-5.1
***
2 Instep length (mm)
168.8±6.5
172.6±7.8
-3.8
***
3 Fibular instep length (mm)
149.0±5.8
153.9± 7.0
-4.9
***
4 Foot breadth diagonal (mm)
93.8±4.0
93.7±5.0
0.1
n.s.
5 Foot breadth horizontal (mm)
91.4±3.9
91.5±4.8
-0.1
n.s.
6 Heel breadth (mm)
58.7±2.8
59.5±3.2
-0.8
*
7 Ball girth (mm)
224.2±9.2
224.2±10.9
0.0
n.s.
8 Instep girth (mm)
221.6±8.2
223.3±10.7
-1.7
*
9 Heel girth (mm)
291.8±10.8
295.6±12.2
-3.8
*
47.5±3.9
47.8±3.8
-0.3
n.s.
10 Sphyrion height (mm) 11 Fibular sphyrion height (mm)
61.3±4.8
61.2±5.4
0.1
n.s.
12 Instep height (mm)
57.9±3.6
58.8±3.9
-0.9
*
13 Toe 1 angle (°)
13.2±4.6
11.6±4.8
1.6
14 Toe 5 angle (°)
9.9±4.9
10.9±5.4 -1.0 †: Japanese – Taiwanese; *: p
