Keywords

1 Introduction

For a long time, the combination between the medical mechanism of traditional Chinese medicine (TCM) massage and modern science and technology has been widely studied. For instance, Gao et al. [1] used sensor information fusion technology, human-computer interaction technology, and three-dimensional simulation to implement TCM massage with robots as a carrier. They developed a robotic system, which consists of a multi-functional massage mechanical arm integrating multiple massage techniques, a vision system for judging the acupoint position, and a control and monitoring system for real-time monitoring. It realized the intelligentization of multiple massage techniques as well as the timely monitoring and feedback of user data. Firouzeh and Bozena [2] from Simon Fraser University of Canada designed a smart massage patch model based on the hot stone massage mechanism to transfer heat to the body. Especially for tight muscles or injured bodies, it could relieve body pain or relax the body. Based on reflexology and electro-acupuncture of foot massage, Felix and Gerald [3] of Applied Science University in Austria developed an electronic foot-reflex therapy stimulation device and stimulated the acupoints of the foot via microcurrent. In this way, it achieved massage effect, thereby enhancing the physical health of the user. Lu [4] of Dalian University of Technology designed and implemented a multifunctional electric pulse physiotherapy instrument, and proposed the method of using a switching power supply step-down circuit to improve power efficiency and ensure output power. He also designed a user-defined mode to meet the special needs of different users by adjusting the efficiency of the switching power supply and forming a therapeutic waveform. The waveform showed a significant TCM massage effect. As above mentioned, in most of the existing studies, TCM massage was mainly achieved with heat conduction technology, automated machinery, electric pulse technology, etc. However, little attention has been paid to the application of TCM massage into product design. Herein, microelectronic technology was used to realize the function of TCM massage. In combination with TCM massage theory, foot scanning data, and design methodology, we built a design model and then applied it to the design project to improve the user’s health and use experience.

2 TCM Foot Massage Theory

Foot massage as an external treatment of TCM belongs to the category of traditional TCM massage and modern Chinese medicine. The feet to a human being is just like the roots to a tree; roots dry up before a tree gets withered, and the feet exhaust before a human being gets old. Foot massage means to compress, rub, shove and knead in the acupoint reflection area of the foot to achieve yin-yang balance, dredge the meridian, promote blood circulation to remove blood stasis, and regulate viscera. It is aimed to promote the transition from the sub-healthy state to healthy state. The theory of foot massage is still under discussion. The mainstream theories are summarized below: ① Theory of meridians: Chinese medicine believes that the foot connects viscera through the meridian; while the meridian passing through viscera and connecting limbs serves as the channel for blood circulation. Foot massage can act on the meridians and acupoints to dredge the meridians, balance the internal organs, improve the healthy level, and enhance immunity. ➁ Theory of nerve reflex: Each organ of the human body has a corresponding reflexion area on the foot, and it realizes regulation mainly by neuromodulation. When the massage is performed in a reflexion area of the foot, the effect is conveyed to the organ via nerve reflexion, thereby achieving the regulation of the corresponding body part. ➂ Qi and blood circle theory: The foot is farthest from the heart and subject to the slowest blood flow. Metabolites and unused minerals in the blood are easily deposited on the foot. When the human body or organs are in a bad state, the circulation of Qi and blood on the foot at one tip is poor, making it easier to deposit waste. Foot massage can help expel these deposits, thus promoting qi-blood circulation and bringing the deposits back to the organs for elimination. ➃ Holographic biomedicine: This theory holds that each body is composed of a number of holographic embryos. The feet are a holographic embryo, where each area has similar biological characteristics to those of corresponding organs. Massaging the reflexion areas on the feet corresponding to the organs can regulate and improve the functions of organs, thus contributing to the mitigated diseases and enhanced health [5].

3 Positioning and Function of Tai-Chong and Yong-Quan Acupoints

3.1 Tai-Chong Acupoint

Taichong acupoint was first proposed in “Lingshu **g Bensu”. It is the original point of the foot Jueyin and liver meridian, and the place where the original Qi of the liver passes and stays. The body surface of Taichong acupoint is located in the depression before the 1st and 2nd metatarsal joints on the dorsal side of the foot, as shown in Fig. 1. Acupuncture and massage on Taichong acupoint can achieve the functions of clearing channels, promoting circulation of qi and blood, nourishing blood, softening the liver, and nourishing liver and kidney. It has a good therapeutic effect on the diseases of limb meridians, qi and blood fluid, the heart system, the kidney system, gynecology and face [6]. For the mitigation of diseases, Tai-chong acupoint is usually found according to the meridians. Acupoint matching treatment not only expands its use range, but also displays the synergistic effect [7].

Fig. 1.
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Location map of Tai-chong acupoint

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3.2 Yong-Quan Acupoint

Yongquan acupoint was derived from “Lingshu Bensu”: “Yong-quan acupoint is the origin of kidney and located at the heart of feet, just like the supporting wood under a well.” Yong-quan acupoint, also known as “Juexin”, “Dichong” or “Diqu”, is one of the commonly used acupoints in foot-Shaoyin kidney meridian. It is located at the bottom of the foot, specifically, the depression in the front of the foot when the foot is stomped, the point of intersection between the first 1/3 and the second 2/3 of the connection line between the head end of the 2nd and 3rd plantar toe seam and the heel of the foot, as shown in Fig. 2 [8]. Yong-quan acupoint is the first acupoint of the kidney meridian. As we know, the kidney not only is the innate foundation and the root of life, but is closely related to the internal organs. Therefore, it can be used to adjust qi in the kidney meridian and enhance the health throughout the whole body [9]. In medicine, it can not only mitigate acute conditions but also benefit the treatment of chronic diseases. Massaging Yong-quan acupoint is found to strengthen the kidney, unblock the yin meridian and the kidney meridian and also regulate Qi and blood of the kidney, thereby improving various functions of the kidney. Existing research has shown that TCM Yong-quan acupoint massage has a very obvious effect in improvement of appetite and sleep, as well as the prevention and treatment of sub-health [10].

Fig. 2.
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Location map of Yong-quan acupoint

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4 The Application Model of the Massage Therapy Instrument on Tai-Chong and Yong-Quan Acupoints

The purpose of the design is not to develop products, but to meet people’s needs [11]. Thus, the application model was built based on the three levels of user needs, which were obtained from the analysis by the Kano model. Then, the TCM acupoint theory, foot scanning image, novel technology, design methodologies and other tools were combined to solve existing demand problems. Finally, the corresponding functions were determined to meet three levels of needs. The application model of the massage physiotherapy instrument on Tai-chong and Yong-quan acupoints is depicted in the figure below (Fig. 3).

Fig. 3.
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The application model of the massage therapy instrument on Tai-chong and Yong-quan acupoints

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4.1 User Analysis

Foot massage is found to be significantly effective in improving human health [12]. Therefore, sub-healthy people are the main target users of the foot massage physiotherapy instrument. Since both Tai-chong and Yong-quan acupoints are located on the feet, this study specifically focused on the young, middle-aged and elderly people in the sub-health state and having no change in foot size.

4.2 Kano Model-Based Demand Analysis of Massage Therapy Instrument on Tai-Chong and Yong-Quan Acupoints

The Kano model was officially proposed by Noriaki Kano, a professor of Tokyo Institute of Technology, at the 12th Japan Quality Management Conference in 1982. This model is a useful tool for categorizing and prioritizing user needs, which analyzes the impact of user needs on user satisfaction and reflects the non-linear relationship between the extent to which user needs are met and user satisfaction [13]. The Kano model divides user needs into three levels: basic needs, expectation needs, and excitement needs. Basic needs refer to the needs that the product function must meet. If this level of needs is satisfied, user satisfaction is guaranteed; otherwise, the user satisfaction will decrease. Expectation needs means that the user expects the product to have certain function; the extent to which the user’s demand is meet has a linear relationship with the level of user satisfaction. The more satisfied this level of needs is, the higher the user satisfaction is, and vice versa. Excitement needs refer to an attribute or function that is unexpected by users. When this level of needs is met, it will surprise users; if not, user satisfaction will not decrease at any time.

According to literature review, expert interviews and questionnaire surveys, the demand analysis of the massage therapy instrument on Tai-chong and Yong-quan acupoints is shown in Table 1.

Table 1. Demand analysis of Massage Therapy Instrument on Tai-chong and Yong-quan Acupoints
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4.3 Function Definition

According to the above three levels of needs, three levels of functions can be defined correspondingly: basic functions, expectation functions, and excitement functions.

  1. 1.

    Basic Functions

(1) Massage positioning

The massage therapy instrument on Tai-chong and Yong-quan acupoints is a product related to the human foot. Therefore, it is necessary to conduct research on the feet of mature youth, middle-aged and older users in a sub-health state. Middle-aged men and women in China belong to mature user groups, so the foot scanning data of this group are applied to this product design research. Figure 4 and Table 2 show the foot size and characteristics of Chinese middle-aged men and women, which are as the reference data. Then, the TCM theory was used to locate Tai-chong and Yong-quan acupoints, and find out the approximate size range of acupoints. According to the above theory and foot scanning data, the location of Tai-chong acupoint can be acquired from 95% of male data and 5% of female data, so as to meet the needs of most people. According to the above data and principle, the location of Yong-quan acupoint is 51.33 mm–56.66 mm from the line connecting the 2nd and 3rd toe seam heads with the heel. Thus, the Yong-quan acupoint massage head should cover a 2.7 mm radius circle centered on the 54.0 mm from the line connecting the 2nd and 3rd toe seam heads with the heel. Similarly, the location of Yong-quan acupoint is 50.00 mm–60.00 mm from the 1st and 2nd metatarsal joints along the depression at an inclination of 10°–15°. Therefore, the Yong-quan acupoint massage head should cover the three-dimensional space area of a sphere with a radius of 2.7 mm from the 55.0 mm from the 1st and 2nd metatarsal joints along the depression with a slope of 12.5°.

Fig. 4.
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13 Foot features and schematics

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Table 2. 13 Foot characteristic parameters
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(2) Massage Techniques

TMC massage techniques refer to specific standardized technical movements of hands or other parts of the limbs, which rub on specific acupoints to produce a benign stimulus and hence prevent or mitigate diseases. There are many types of massage techniques, which can be divided by kinematic characteristics to rolling, vibrating, rubbing, friction, hitting, pinching, and pressing. Various stimulation modes can be set on kneading, tap**, acupuncture, and massage [14]. At present, the technical methods applying these stimuli include the physical stimulation of the mechanical arm and the electronic stimulation of the microelectronic electrical pulse. The mechanical arm simulates the human hand to perform a specific standard massage technique. The electric pulse of microelectronic technology simulates the stimulation of massage through different current waveforms.

  1. 2.

    Expectation Functions

(1) Portable and Beautiful

The product designed must be portable. A small-size product is easy to carry. Since the designed instrument is aimed at the two acupoints of Tai-chong and Yong-quan, the required functional parts should meet the miniaturization to make it convenient for users to take. Good products need not only internal and practical functions, but also external aesthetics. Product appearance reflects practical functions and emotional functions. The instrument designed in this study is a medical care product, and users have soft, safety, peace and other emotional needs. Therefore, the shape of the instrument should be round and soft in a curved way.

(2) Humanization

The humanization of the Tai-chong and Yong-quan acupoint acupressure massage therapy instrument is mainly reflected in the use of the product, materials, operation interface and other aspects. In terms of use, since the Tai-chong and Yong-quan acupoint are located on the upper and lower sides of the foot, respectively, it is possible to consider the use of the foot toe clamp. The clam** use should meet the comfort of the user. The shape of the clam** part and the contact part of the foot should be closely fitted, and the material should be soft. In terms of materials, different materials can give users different visual and tactile sensations. Foot acupressure massage therapy device is a medical care product that needs to be used in contact with the human foot. Therefore, the material in contact with the human body should be selected to be soft and not harmful to the skin. Soft products are easy to make people feel comfortable, and soft materials can also cushion the pressure of interaction forces when users use the products. Materials that are harmless to the skin would guarantee the health and safety of users. The operation interface should be consistent with the user’s basic usage habits, and keep it simple. For example, set the commonly used function key requirements in an obvious location to facilitate the user’s use.

  1. 3.

    Excitement Functions

Excitement functions involve health detection, Bluetooth technology, and voice functions. Sub-healthy people are at the tip** point of health and disease, physically and mentally unhealthy. For example, to increase the humanization of the product by, it is advisable to provide the functions of health detection and voice reminders, or to connect the instrument to the user’s mobile phone terminal via Bluetooth technology. This connection will allow to record and analyze the health status and give corresponding suggestions. It eventually helps the user to maintain a positive mental state from the aspects of vision and hearing.

5 Product Design of the Foot Microelectronics Physiotherapy Instrument on Tai-Chong and Yong-Quan Acupoints

5.1 Foot Microelectronics Physiotherapy Instrument on Tai-Chong and Yong-Quan Acupoints

The acupoint massagers in the market can be mainly divided into non-energy-consuming and energy-consuming types, which rely on physical power and electric power respectively. In the energy consumption category, most of the foot massagers are household multi-acupoints massagers, which can perform deep-level massage, but are not portable. Non-energy-consuming foot massage devices require users to have a certain knowledge of TCM acupoints; in addition, the use mode is not modern enough. As a result, foot massage devices cannot achieve good results in most cases. It is urgent to develop a small massage product that can accurately act on fixed acupoints and realize the professionalization and convenient use of acupoint massage.

In the specific design, the foot microelectronics physiotherapy instrument on Tai-chong and Yong-quan acupoints consists of 1) the pulse generator end body, 2) the massager connector with a toe grip in the middle, 3) the Tai-chong acupoint massage head, and 4) the Yongquan acupoint massage head, as shown in Fig. 5. According to the above analysis, the fixed position of the massage head is determined to realize the massage positioning, and different radio waves of the microelectronic technology are used to implement the massage technique. In terms of aesthetics, the instrument mainly has a simple and round shape with the off-white as the main color, making users feel comfortable visually. In terms of portability and humanization, the overall instrument is small and the massager connector with a toe grip in the middle is easy to take. In addition, the left and right sides of the middle toe grip are inwardly curved and concave, in order to maintain the comfort of the clam** between the first toe and the second toe. Also, the instrument is a plastic shell outside and a circuit inside which connects the massage heads of Tai-chong and Yong-quan acupoints. A model of the designed instrument is given in Fig. 6.

Fig. 5.
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Product schematic

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Fig. 6.
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Product physical map

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5.2 Evaluation of the Designed Instrument

  1. 1.

    Fuzzy Evaluation Model

    1. (1)

      Determine the evaluation indicator set and the weight matrix. Evaluation indicator set U={u1, u2,…, un}. Each indicator data is kept as parallel as possible, so that there is no crossover factor. A weighting coefficient is assigned to each indicator to obtain a weight matrix A = [a1, a2,…, an], which satisfies \( \sum\limits_{i = 1}^{n} {a_{i} = 1} \). The level of the user’s recognition and satisfaction with the indicators are expressed by fuzzy concepts such as excellent, good, general, and poor. The evaluation indicators are evaluated to obtain the evaluation set V = {v1, v2,…, vm}. In the following evaluation schemes, the satisfaction level of V = (100, 75, 50, 0) is extracted.

    2. (2)

      Determine the fuzzy relation matrix. The evaluation index ui(i = 1, 2,…, n) is evaluated accordingly, and the evaluation value rij (j = 1, 2,…, m) in the j-th semantic of the i-th index is obtained to satisfy \( \sum\limits_{j = 1}^{m} {r_{{_{ij} }} } = 1 \). Similarly, the fuzzy concepts such as excellent, good, average, and poor are used as the set of evaluation vocabulary j to evaluate each evaluation index ui. Then, the proportion of the number of people in the comment set in each indicator is got to generate the fuzzy relationship matrix:

$$ R = \left[ {\begin{array}{*{20}c} {r_{11} } & {r_{{_{12} }} } & \ldots & {r_{1m} } \\ {r_{{_{21} }} } & {r_{22} } & \ldots & {r_{2m} } \\ \ldots & \ldots & \ldots & \ldots \\ {r_{n1} } & {r_{n2} } & \ldots & {r_{nm} } \\ \end{array} } \right] $$

Calculate the decision matrix. Based on the fuzzy relation matrix and the weight matrix, the decision matrix is calculated as:

$$ B = AR = \left[ {\begin{array}{*{20}c} {a_{1} } & {a_{2} } & \ldots & {a_{{_{n} }} } \\ \end{array} } \right]\left[ {\begin{array}{*{20}c} {r_{11} } & {r_{12} } & \ldots & {r_{1m} } \\ {r_{21} } & {r_{22} } & \ldots & {r_{2m} } \\ \ldots & \ldots & \ldots & \ldots \\ {r_{n1} } & {r_{n2} } & \ldots & {r_{nm} } \\ \end{array} } \right] = \left[ {\begin{array}{*{20}c} {b_{1} } & {b_{2} } & \ldots & {b_{n} } \\ \end{array} } \right] $$

where \( bj = \sum\limits_{i = 1}^{n} {a_{i} a_{{_{ij} }} } \). Each evaluation result denotes the membership degree of each comment set.

  1. 2.

    Design Evaluation

A total of 50 senior product designers were invited to evaluate the product and score the specific functions according to the three functional categories above. From literature review and the above discussion, it can be concluded that the influence weight of the three functional categories on user experience is: A = [0.3, 0.5, 0.2] for basic, expectation and excitement functions respectively. In terms of the excitement function, the influence weight of health detection, Bluetooth function and Voice function is 0.6, 0.2 and 0.2, respectively. The user experience score of each category function is equal to the value of B • VT, as shown in Table 3.

Table 3. Evaluation score of the designed instrument
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From the above table, the score of basic function of the instrument developed in this study is 94.00, indicating an excellent satisfaction of basic needs. The score of expectation function is 85.10, suggesting a good satisfaction of expectation needs. The score of excitement function is 0.00, presenting a poor satisfaction of excitement needs. User experience is scored to be 70.70 points, in an average level. In terms of the excitement function, health detection, voice function and Bluetooth technology have not been applied in practice. Thus, the performance of the excitement function requires a further study.

6 Conclusion

Based on the Kano demand model, the three functions of the foot microelectronics therapy instrument on Tai-chong and Yong-quan acupoints were defined. The design model was established in a combination with the modeling design theory, man-machine engineering, color design theory, acupoint theory of TCM and foot scanning data. Finally, through the evaluation of the designed instrument, it is concluded that this acupoint physiotherapy device can improve the user experience from three functional levels and effectively perform deep-level massage on the acupoints, thereby enhancing the health of users. The evaluation results prove the validity of this model. Still, this study is subject to some limitation. The future study should examine the accuracy of the acupoint location. This paper not only expands the application of the Kano demand model, but also provides new insights into the innovative design of acupoint physiotherapy products.