The Effect of Mind-Body Exercise on Sustainable Psychological Wellbeing Focusing on Pilates

The purpose of this study was to analyze the theoretical model of mind–body exercise and to examine its effect on psychological wellbeing focusing on Pilates. A total of 219 surveys from Pilates participants were analyzed using structural equation modeling. The result of this study indicated service quality has a significant direct effect on participation satisfaction (+). Service quality does not have a significant direct effect on sustainable participation intention. Participation satisfaction has a significant direct effect on positive emotion (+). Participation satisfaction has a significant direct effect on negative emotion (−). Participation satisfaction has a significant direct effect on sustainable participation intention (+). Service quality has a significant indirect effect on sustainable participation intention mediated by participation satisfaction (+). The findings of this study will be valuable data for healthcare experts to establish more effective mental health strategies concerning mind–body exercise.


Needs of Study
As maintaining positive emotions plays a central role in mental health [1,2], many previous studies have analyzed the effects of physical exercise and sports on mental health.However, few studies have focused on the effectiveness of mind-body exercise.Mind-body exercise can be referred to as physical activity that includes unique characteristics such as internal attention and a mindful component [3].Mind-body exercise focuses on the inner training of the body and tends to have mild physical activity level compared to other competitive sports, resulting in less chance of injury.In other words, mind-body exercise is an effective method to increase psychological wellbeing by focusing on the mind through physical activity.Recently, Pilates has gained popularity as a mind-body exercise which draws over 9 million participants in the U.S. [4].The psychological benefits of Pilates, in particular, have already been verified in previous studies.Studies have reported that participation in Pilates significantly increased self-esteem and positive emotion [5].This positive psychological effect increased as the participation frequency and intensity increased [5,6].Therefore, to maximize the advantage of Pilates, the sustainable participation needs to be ensured.
Thus, if a theoretical model explaining the effects of Pilates and its effects on psychological wellbeing with the sustainable participation is identified, it might provide valuable data for healthcare experts to establish more effective mental health strategies through mind-body exercise.

The Pilates as the Mind-Body Exercise
Mind-body exercise can be referred to as a physical activity which is linked to the temporary self-contemplative mental state through internally-directed mind attention [3,5,6].This internal attention and mindful component are distinctive characteristics from conventional body-centered aerobic or muscular exercise [3,5,6].A mind-body-oriented approach is related to the activation of intrinsic energy and maximizes self-control and empowerment by being aware of breathing and proprioceptive sensations with low intensity physical movement [3,5,6].Mind-body exercise makes participants feel the conscious connection of mind, body and emotions that increases their ability and capacity to control negative mental states [7].In this line of definition, Pilates was recently suggested as one of the effective mind-body exercises [8].Pilates was originally founded by Joseph Pilates during the 1920s and involves both floor-based and the use of specialized equipment [8].The basic elements of Pilates consist of breathing, core stability, flexibility, muscle control, mind-body connection, posture, and strength [8].Particularly, the core concept of Pilates is control of the physical body by the mind.Therefore, Pilates might fit into the category of mind-body exercise, and this study investigated participants from a local Pilates center to analyze the effectiveness of mind-body exercise.

Service Quality of the Mind-Body Exercise
The quality of services of the sport center is one of the most important factors affecting various psychological variables [9].Service quality has been identified in several ways by previous studies.For example, Parasuraman, Zeithaml, and Berry [10] defined service quality as the perceived degree toward the actual service that they are provided compared to user expectations.Bitner and Hubbert [11] defined service quality as "the consumer's overall impression of the relative inferiority/superiority of the organization and its services" (p.77).Zeithaml, Parasuraman, and Berry [10] defined service quality as "the extent of discrepancy between customers' expectations or desire and their perceptions" (p.19).Based on the definitions above, the decreased gap between customer's expectation and perception would increase service quality.Service quality can be divided into two dimensions which are intangible services and tangible services [10].Intangible services include reliability, responsiveness, competence, courtesy, credibility, security, access, communication, and understanding.Intangible services have the unique characteristics that customers cannot see service quality before they purchase, customers consume it at the same time it is produced, and customers cannot store after consuming it [11,12].On the other hand, tangible services including the appearance of physical facilities and equipment, feature the opposite characteristics to intangible services [11,12].Since intangible services are delivered in tangible physical surroundings, both tangible and intangible services interact with one another [13].So, it is reasonable to measure both tangible and intangible services.
Based on the concept of tangible and intangible services, SERVQUAL was developed, which is one of the widely adopted scales in service quality studies and is considered as almost the first attempt to measure the service quality [14].SERVQUAL is intended to measure the gap between customers' expectation and perception toward the service which they are provided [14].Although SERVQUAL adequately assesses the service quality in a variety of industries and research fields, sport researchers might need a more focused scale on sport.For this reason, Kim and Kim [15] developed QUESC (QUality Excellence of Sports Centers) which measures service quality in sport specifically.Kim and Kim [15] analyzed the customers from sport centers and found 11 distinct dimensions of service quality in sports including ambiance, employee attitude, reliability, information, programming, personal consideration, privileges, price, ease of mind, stimulation, and convenience.This QUESC scale has been widely adopted by various service quality studies in sport [16].Therefore, this study investigated the service quality of the Pilates center with the factors such as employee reliability, ambiance, program offered, and price based on the QUESC.

Participation Satisfaction of the Mind-Body Exercise
Oliver [17] defines customer satisfaction as "a judgment that a product or service feature, or the product or service itself, provides a pleasurable level of consumption-related fulfillment" (p.13).Based on this definition, leisure satisfaction can be interpreted as the degree of perceived positive evaluation derived from participation in leisure activities [18].Satisfaction can be divided into the two dimensions of transaction-specific and overall satisfaction [19,20].Transaction-specific satisfaction refers to satisfaction derived from each separate service encounter even if it is provided by the same service provider, company or organization.Overall satisfaction, on the other hand, refers to the aggregation of each transaction-specific satisfaction [19,20].As a result, transaction-specific satisfaction changes with each service encounter while overall satisfaction is relatively consistent since it is the average of each service encounter [21].Hence, this study treats participation satisfaction of mind-body exercise as participants' overall satisfaction with Pilates.

Sustainable Psychological Wellbeing
To examine the concept of sustainable psychological wellbeing more effectively, this study divided it into the two parts of psychological wellbeing and sustainable participation.First, the World Health Organization (WHO) identified mental health as "a state of well-being in which the individual realizes his or her own abilities, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to his or her community" [22].In addition, psychological well-being can be explained as one's subjective feelings of pleasure and happiness, which is the presence of a positive mood and the absence of negative mood [23,24].Thus, maintaining positive emotions plays a central role in mental health [25].It is well known that positive emotions make people more optimistic and confident, and individuals tend to get along well with others in a society [1,2].Therefore, happier people with positive emotions might have a healthier lifestyle and more positive social relationships with more friends [24,26].Especially, when people set specific personal goals, positive and negative emotions arise as the goal is achieved or not [27,28].These positive and negative emotions can be analyzed separately since they are negatively correlated yet clearly differentiated [27,28].Thus, this study focuses on positive emotions and negative emotions as indicators of the psychological wellbeing state.
Second, sustainable participation is a crucial factor to extend the psychological wellbeing state derived from physical exercise.As most participants who first tried leisure sports quit within 6 months, sustainable participation has been continually studied in the sport research field [29].Sustainable participation was studied by measuring the level of future intention of sustainable participation based on the concept of behavioral intention [29].Behavioral intention is explained as the willingness to perform specific behaviors, and measuring behavioral intention can be a reliable predictor of actual future behavior, as a stronger intention to perform a behavior indicates a higher possibility of performing the behavior [30].Thus, this study also measures the level of sustainable participation intention to explain the sustainable participation in mind-body exercises such as Pilates.

Relationship among Service Quality, Participation Satisfaction, Psychological Wellbeing, and Sustainable Participation Intention
The purpose of this study is to provide a theoretical model of sustainable psychological wellbeing through mind-body exercise by identifying the relationship among service quality, participation satisfaction, psychological wellbeing, and sustainable participation intention in Pilates.First, previous studies [9,16,31] indicated the positive effect of service quality on customer satisfaction.Second, service quality has been identified as positively affecting sustainable participation intention [9].Third, Theodorakis, Kaplanidou, and Karabaxoglou [16], Kim, Sung, Park, and Dittmore [32], and Mancini [33] found the positive relationship between satisfaction of leisure activities and psychological wellbeing.Fourth, prior studies [9,29] found that participation satisfaction has a positive effect on sustainable participation intention.Fifth, Wakefield and Blodgett [34] found that service quality has an indirect effect on behavioral intentions mediated by satisfaction.Kuo, Wu, and Deng [35] also found that customer satisfaction mediates the effect of service quality on behavior intention.Based on these prior findings, we propose the following hypotheses: Hypothesis 1. Service quality will have a positive effect on participation satisfaction.Hypothesis 2. Service quality will have a positive effect on sustainable participation intention.Hypothesis 3. Participation satisfaction will have a positive effect on the positive emotion.Hypothesis 4. Participation satisfaction will have a negative effect on the negative emotion.
Hypothesis 5. Participation satisfaction will have a positive effect on sustainable participation intention.Hypothesis 6. Service quality will have an indirect effect on sustainable participation intention mediated by participation satisfaction.

Participants
We used convenience sampling to approach participants of this study.A total of 350 surveys were distributed (a self-administered questionnaire with the presence of researchers) in nine different Pilates centers in Seoul, South Korea between June 11 and 22, 2018.A total of 262 surveys were returned.However, 43 were discarded due to excessive missing values, resulting in 219 usable surveys.Of the participants, 72.6% were female and 27.4% were male.Most participants were aged 20 to 29 (58.0%)followed by 30-39 (19.6%).The majority of subjects participated in Pilates two times weekly (60.8%).Table 1 presents the participants' demographic information.

Instruments
The survey distributed to participants consisted of five sections including service quality, participation satisfaction, psychological wellbeing, sustainable participation intention, and demographic information.Kim and Kim's [15] QUESC (QUality Excellence of Sports Centers) was adopted and modified to measure service quality.QUESC was translated and used in previous studies in Korea [36,37].In this study, we measured service quality with the four attributes of 1: employee reliability encompassing adequate knowledge, skills, and consistent services.2: ambiance representing adequate space, comfortable temperature, cleanliness, and modern equipment.3: program offered considering level-specific programs, well-organized program, and variety of program.4: price indicating resealable price and cost-effectiveness.A five-point Likert scale was used ranging from 1 (strongly disagree) to 5 (strongly agree).A higher score indicates that the respondent experienced higher service quality from the Pilates center.Participation satisfaction was measured using satisfaction items from Reynolds and Beatty [38].A translated version of Reynolds and Beatty's [38] satisfaction items were used by previous studies in Korea [39][40][41] and reliability and validity were ensured.A total of four items were used for measuring participation satisfaction.A five-point Likert scale was adopted ranging from 1 (strongly disagree) to 5 (strongly agree).A higher score indicates that the respondent features a higher participation satisfaction of Pilates exercises.Psychological wellbeing was estimated by measuring the level of positive and negative emotions.A positive emotions (four items) and negative emotions (four items) scale was adopted and modified from a Korean version of the anticipated emotion scale.Anticipated emotion scale was originally developed by Perugini and Bagozzi [28] and previous studies in Korea [42][43][44] translated this scale from English to Korean and verified the reliability and validity of the translated version.A five-point Likert scale was used ranging from 1 (strongly disagree) to 5 (strongly agree).Concerning positive emotion, a higher point indicates that the respondent has a higher positive anticipated emotion toward overall life.Regarding negative emotion, a higher point indicates that the respondent has a higher negative anticipated emotion toward overall life.To assesses sustainable participation intention, we adopted three items from previous studies of sustainable participation on leisure sports [29,45].The items measured respondent's intention to continue participation in Pilates.A five-point Likert scale was used ranging from 1 (strongly disagree) to 5 (strongly agree).A higher score indicates that the respondent has a higher continuous participation intention for Pilates.

Data Analysis
SPSS Version 20.0 was used to compute descriptive statistics, Cronbach's alpha and squared correlations.The two-step approach for structural equation modeling (SEM) was employed based on Anderson and Gerbing's [46] suggestion.Therefore, confirmatory factor analysis (CFA) assessing the psychometric properties of the measurement model was performed in the first step, and the SEM was examined to investigate the relationship among variables using AMOS version 20.0.The overall model fit was assessed based on the following fit indices [47]: Chi square (χ 2 ), chi square/degrees of freedom (χ 2 /df) (<5.0), comparative fit index (CFI) (>0.90), root mean square error of approximation (RMSEA) (<0.08), root mean square residual (RMR) (<0.08), and the standardized root mean square residual (SRMR) (<0.08).The reliability of constructs and their corresponding indicators were evaluated based on Cronbach's alpha [48].The convergent validity was evaluated by the construct reliability (CR) with a 0.70 threshold and average variance extracted (AVE) with a cutoff value of 0.50 [48].Discriminant validity was evaluated based on Lichtenstein, Netemeyer, and Burton [49] which stated that if AVE for all latent variables are larger than its squared correlations, discriminant validity is possessed.A bootstrapping procedure using 5,000 bootstrap samples and a 95% confidence interval (CI) was conducted to test the indirect effect of service quality on sustainable participation intention mediated by participation satisfaction [50].

Discussion
This study identified the relationship among service quality, participation satisfaction, psychological wellbeing, and sustainable participation intention in mind-body exercise, the Pilates in particular.First, service quality has a significant direct effect on participation satisfaction supporting research hypothesis 1.This result is consistent with previous studies [9,16].Previous studies indicated the importance of service quality on satisfaction including sporting events and sport participation [9,16].However, this study specifically showed the positive effect of service quality on participation satisfaction in Pilates which is one of the well-known mind-body exercises.This study included employee reliability, ambiance, program offered, and price as attributes of service quality and these attributes overall explained the influence of service quality on satisfaction.A previous study of Pilates participants also suggested instructor ability, quality of program, facility, and price as important factors affecting customer loyalty [51].Nevertheless, service quality does not have a significant direct effect on sustainable participation intention, which does not support research hypothesis 2. This result is not consistent with previous studies [9,52].This difference could be caused by type of exercise.This study solely used data from Pilates participants while previous studies [9] included participants from fitness centers which featured a greater portion of weight lifting and swimming (69.5%) among participants.In addition, the ethnic and cultural differences may affect results as this study used participants in Korea while Theodorakis and Alexandris [52] included participants in Greece.Therefore, to explain the different results between this study and previous studies [9,52], follow-up studies are required.
Second, participation satisfaction has a significant positive effect on positive emotion (Hypothesis 3) and a negative effect on negative emotion (Hypothesis 4).This result is consistent with previous studies [16,27,28,32,33].We found evidence that the satisfaction derived from mind-body exercise participation can be a valuable psychological factor maintaining positive emotions and eliminating negative emotions.Based on prior studies [53][54][55], less frequent and intense positive emotional experiences result in a higher level of social anxiety, which in turn, leads to less chance to develop proper problem-solving skills, social interactions and relationships.Therefore, the benefits of possessing positive emotions affects not only personal life but also society.Especially, mind-body exercise (yoga) is thought of as an effective exercise for enhancing positive emotions, psychological wellbeing and resilience to stress [56].According to Granath, Ingvarsson, von Thiele, and Lundberg [57], participation in a 10-week yoga class improved self-perceived quality of the life by decreasing stress, stress behavior, and exhaustion.Lavey, Sherman, Mueser, Osborne, Currier, and Wolfe [58] analyzed the effect of yoga class participation by focusing on psychiatric inpatients.They found participation in yoga classes make patients feel less tension, anxiety, depression, dejection, anger, and hostility.Brisbon and Lowery [59] studied the effect of long-term yoga classes (2-5 years) and also found positive effects on mental health by increasing mindfulness while decreasing stress.Among Pilates participants, individuals with higher participation frequency indicated a higher level of positive emotion compared to those with lower participation frequency [6].An eight-week participation in Pilates significantly increased participants' self-esteem [5].Thus, this study added further evidence of the psychological benefits of Pilates specifically.
Third, participation satisfaction has a significant direct effect on sustainable participation intention supporting research hypothesis 5.In addition, service quality has a significant indirect effect on sustainable participation intention mediated by participation satisfaction supporting research hypothesis 6.These results support previous studies [9,29,34,35].As the word sustainable indicates "able to be maintained at a certain rate or level" [60], continuous participation is an essential factor for sustainable psychological wellbeing by extending and maintaining the psychological benefits from participation in mind-body exercise.This study emphasizes the importance of participation satisfaction and service quality as the effective factors that increase the sustainable participation intention.In this study, service quality only has an influence on sustainable participation intention mediated by participation satisfaction while participation satisfaction directly affected sustainable participation intention.Therefore, participation satisfaction may be a stronger factor predicting sustainable participation intention compared to service quality.Prior research also suggested that consumer satisfaction is a more salient factor affecting repurchase intention compared to service quality [9].
Based on the finding of this study, the following practical implication can be suggested.The result of this study indicated that service quality increased participation satisfaction, and in turn, participation satisfaction increased both positive emotion and sustainable participation intention.Moreover, service quality indirectly affected the psychological wellbeing indicators such as positive emotion and negative emotion and was mediated by participation satisfaction.Therefore, two key factors for psychological wellbeing and sustainable participation intention might be service quality and participation satisfaction.Based on Jung, Lee, and Kim [61], the instructor's communication ability is one of the most important factors increasing the participation satisfaction of Pilates.Specifically, the use of effective transformational leadership including charisma and intellectual stimulation could make Pilates participants experience flow more effectively, in turn maximizing participation satisfaction [62].In addition, Pilates instructor's teaching skills and theoretical knowledge of physical training could also increase participation satisfaction [63].In terms of service quality, selecting and focusing on the four key factors of employee reliability, ambiance, program offered, and price would more effectively improve participation satisfaction when the Pilates center does not have sufficient resources to improve the service quality-related attributes.
This study is an initial attempt to analyze the relationships among service quality, participation satisfaction, psychological wellbeing, and sustainable participation intention for Pilates.Nevertheless, this study has some limitations that follow-up studies need to consider.First, this study included Pilates participants only in Korea.Since there might be cultural and ethnical differences between Korean and participants from other countries, future studies need to include participants from a wider range of countries.Second, this study did not analyze differences among demographic information such as age, gender, year of exercise, exercise frequency and intensity.In addition, there might be additional factors that affect sustainable participation intention, such as individual motivations or attitudes towards sport.Therefore, future studies need to include additional variables to provide further data for practical implications.

Conclusions
Although over 9 million people participate in Pilates [4], making it one of the most popular mind-body exercises, the psychological benefits of Pilates have not been adequately examined.The contribution of this study can be highlighted as providing a theoretical model of sustainable psychological wellbeing through mind-body exercise.This study supports the role of service quality and participation satisfaction on psychological wellbeing and sustainable participation intention in Pilates.In addition, this study identified four specific service quality attributes of employee reliability, ambiance, program offered, and price affecting participation satisfaction in Pilates.The findings of this study might be used for further research on both effective marketing strategies for Pilates and maximizing psychological benefits from mind-body exercise.

Figure 1 .
Figure 1.Proposed structural model.Solid lines indicate significant paths at p < 0.05.Dotted lines indicate insignificant paths.Values shown next to the solid lines are standardized regression coefficients.

Table 3 .
Result of structural equation modeling.