Identifying core elements of professional identity among Japanese physiotherapists: a scale revision and validation

Identifying core elements of professional identity among Japanese physiotherapists: a scale revision and validation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Identifying core elements of professional identity among Japanese physiotherapists: a scale revision and validation Kayoko Nonaka, Maiko Ishino, Takafumi Saito, Takuro Ikeda, Akihiro Shimiya, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8260003/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Objectives: To develop a revised version of the Professional Identity Scale for Physiotherapists and clarify core elements of professional identity among Japanese physiotherapists. Design: A nationwide cross-sectional web-based survey. Setting: The survey was conducted across 499 institutions employing physiotherapists in Japan. Participants: A total of 1 037 physiotherapists participated in the study (mean age = 32.3 years; 68.5% male, 31.0% female, and 0.5% unspecified gender). Main outcome measures: Primary outcome measures were the factor structure and internal consistency of the newly developed Professional Identity Scale for Physiotherapists. Secondary outcome measure included correlations between this scale and the Burnout Scale to assess criterion-related validity. Results: Exploratory factor analysis yielded a five-factor structure (“Development of and Contribution to the Professional Group,” “Practical Skills,” “Client-Centered Support,” “Sense of Adaptability,” and “Orientation Toward Contributing to Interprofessional Collaboration”) comprising 28 items, after excluding 9 items from the original 37-item version. Cronbach’s α coefficient ranged from 0.85 to 0.92 for the five factors, with an overall value of 0.96. Criterion-related validity was evidenced by significant correlations with the Burnout Scale: the total identity score was negatively correlated with emotional exhaustion ( r = -0.322, p < 0.001) and depersonalization ( r = -0.281, p < 0.001) and positively correlated with personal accomplishment ( r = 0.498, p < 0.001). Conclusions: The revised Professional Identity Scale for Physiotherapists is a reliable and valid instrument for assessing professional identity among physiotherapists. It provides a practical framework for research and educational initiatives aimed at fostering professional identity and mitigating burnout. In addition, the scale may contribute to curriculum development, competency-based training, and international comparative studies focused on professional identity within the health professions. Professional identity Physiotherapists Scale development Factor analysis Psychometric properties Burnout Contribution of the Paper This study developed a revised version of the professional identity scale tailored for physiotherapists in Japan, improving its clarity, structure, and psychometric properties. Exploratory factor analysis identified a robust five-factor structure with high internal consistency, providing a clear conceptual framework for understanding professional identity in physiotherapists. Demonstration of criterion-related validity through significant correlations with burnout dimensions, highlighting potential utility in identifying professionals at risk of burnout and informing interventions. Introduction Professionalism refers to the external expectations placed on professionals, including codes of conduct, ethical standards, appropriate behaviors, attitudes, and relationships required in the practice of a profession [ 1 ]. The American Physical Therapy Association identifies seven core values that constitute professionalism in physiotherapists: accountability, altruism, compassion, excellence, integrity, professional duty, and social responsibility [ 2 ]. While professionalism reflects externally endorsed standards and expectations, professional identity involves the internalization of these values. It is defined as an individual’s understanding and acceptance of the beliefs, values, attitudes, and roles associated with their professional group [ 3 , 4 ]. In this sense, professional identity captures how individuals perceive themselves as professionals, moving beyond external norms to construct an internal sense of professional self. Understanding professional norms and adopting core values are essential in developing a professional identity [ 5 ]. In addition, professionalism and professional identity are closely linked, with the latter enhanced through educational efforts that promote professional values. Individuals with a strong professional identity tend to exhibit higher stress tolerance and are less susceptible to burnout, indicating the need to focus on education that enhances professional identity [ 6 , 7 ]. Since the early 2000s, research on professional identity has grown [ 4 ]. However, a scoping review revealed limited focus on rehabilitation professionals, with only 19% ( n = 10) of studies addressing physiotherapists [ 8 ]. Among these, only two studies [ 9 , 10 ] examined practicing physiotherapists, emphasizing the role of professional socialization, while the others focused on students [ 11 , 12 ]. Regarding research on healthcare professional identity in Japan, most scale development efforts have focused on nurses, with only three studies addressing occupational therapists [ 13 ]. Notably, there are still few reliable and valid scales specifically designed to assess the professional identity of physiotherapists [ 14 – 16 ]. An exception is Nonaka et al. [ 17 ] who developed a professional identity scale specifically for physiotherapists in Japan, reflecting their occupational values, roles, and interprofessional collaboration within Japanese clinical contexts. This 37-item measure was developed through a literature review and expert consensus and demonstrated high reliability and a clear factor structure. However, to enhance its practical utility in clinical settings, the scale must be refined into a more concise and practical form. Accordingly, following the guidelines proposed by DeVellis [ 18 ], we combined statistical criteria—such as factor loadings and cross-loadings—with expert review to ensure both content validity and conceptual clarity. This study evaluates the reliability and validity of the revised version of the Professional Identity Scale for Physiotherapists. Given the limited international research on professional identity among physiotherapists, this newly developed instrument represents a novel contribution to the field and is expected to serve as a valuable tool for both educational and research purposes, in Japan and beyond. Methods The dataset was obtained from a questionnaire survey originally conducted to develop the initial version of the scale [ 17 ]. We adopted a snowball sampling approach using professional networks to recruit participants, and data were collected via a web-based questionnaire (Google Forms) between June 1 and September 30, 2023. Most widely accepted guidelines for factor analysis generally consider a minimum of 200–300 participants as necessary to obtain stable factor solutions [ 19 ]. To ensure stable factor loadings and a reliable psychometric evaluation, we set our target sample size at 500 participants. The survey was distributed to 499 institutions nationwide that employ physiotherapists, and ultimately, valid responses were obtained from 1 037 physiotherapists, exceeding the recommended threshold. As the web-based questionnaire required responses to all items before submission, no missing data were generated. The questionnaire included the following components: gender, age, years of clinical experience, final educational level (specialized training college, four-year college, master’s or doctoral degree), job position (general staff/others, unit chief/team leader, section chief, executive level), the initial version of the Professional Identity Scale for Physiotherapists [ 18 ], and the Japanese version of the Burnout Scale [ 21 ]. Professional Identity Scale for Physiotherapists The preliminary psychometric properties of the original 37-item Professional Identity Scale for Physiotherapists have already been reported in [ 17 ]. Given that the original publication is in Japanese, we briefly outline the development process here for the benefit of international readers. A scale to assess the professional identity of physiotherapists was developed and validated through a three-phase process. In the first phase, focus group interviews were conducted with 13 physiotherapists working in clinical and educational settings. Through these interviews, an initial pool of 50 items was generated and subsequently refined. Based on expert reviews, 10 items were deleted, resulting in a provisional 40-item version. In the second phase, a preliminary survey was conducted with 186 physiotherapists to examine the scale’s reliability and factor structure. Based on item-total correlation analysis, 3 items were removed, resulting in a 37-item version. Exploratory factor analysis identified a four-factor structure; Cronbach’s α was 0.95 for the total scale and between 0.81 to 0.90 for the four subscales. Notably, during this preliminary stage, the authors prioritized comprehensive content coverage over strict statistical criteria, resulting in a 37-item version that included some items with factor loadings below 0.4 or with cross-loadings. The goal was to ensure that the initial scale comprehensively captured the full range of professional identity concepts identified in their qualitative research. In the third phase, a large-scale web-based survey was conducted with 1 037 physiotherapists to further validate the scale. Exploratory factor analysis using the scree plot criterion confirmed a five-factor structure. The cumulative variance explained by these five factors was 62.62%. The five factors were: Development of and Contribution to the Professional Group (8 items), Professional Perspective (8 items), Practical Skills (8 items), Sense of Adaptability (4 items), and Orientation Toward Contributing to Interprofessional Collaboration (9 items). The factor labels were determined by consensus among a panel of 10 expert physiotherapists with more than 10 years of clinical experience. Cronbach’s α was 0.97 for the total scale and between 0.85 to 0.94 for the five subscales, indicating high internal consistency. Japanese version of the Burnout Scale To assess criterion-related validity, the scale was compared with the Japanese version of the Burnout Scale, which comprises three independent subscales: emotional exhaustion—psychological fatigue and feelings of being emotionally drained, depersonalization—detachment or indifference toward others (e.g., avoiding bothersome interpersonal interactions), and personal accomplishment—a sense of competence and successful achievement in one’s work. Each subscale is measured using a 5-point Likert scale from 1 ( never ) to 5 ( always ) [ 20 ]. Statistical analyses We conducted an item reduction process to develop a revised version of the original 37-item Professional Identity Scale for Physiotherapists based on the criteria of both statistical and content validity. Specifically, exploratory factor analysis was employed to assess the factor structure, and items with factor loadings below 0.4 or cross-loadings exceeding 0.3 were excluded. Content validity was assessed by an expert panel, leading to the removal of items that were conceptually ambiguous or redundant. This process was carried out in accordance with the guidelines proposed by DeVellis [ 18 ], who emphasizes that item selection should be guided by both statistical indicators and expert judgment to ensure content validity and conceptual clarity. We conducted exploratory factor analysis using the revised version of the scale. The maximum likelihood estimation method with promax rotation was used for factor extraction, and the number of factors was determined based on the scree plot. Sample adequacy was verified using the Kaiser-Meyer-Olkin test and Bartlett’s test of sphericity. Items were selected based on eigenvalues ≥ 1, factor loadings ≥ 0.4, and minimal cross-loading (loadings < 0.3 on other factors). Cronbach’s α coefficients were calculated to assess internal consistency. Criterion-related validity was evaluated by Spearman’s rank correlation coefficient between the total score and five factors of the revised version of the Professional Identity Scale for Physiotherapists and the three subscales of the Japanese version of the Burnout Scale. A panel of 10 experienced physiotherapists, each with more than 10 years of clinical experience, interpreted the factor analysis results and named the factors through consensus. Statistical analyses were performed using IBM SPSS Statistics for Windows version 29. The statistical significance was defined as a 2-tailed p-value < 0.05. Results Participant characteristics A total of 1 037 valid responses were included in the analysis. The sample consisted of 710 males (68.5%), 322 females (31.0%), and 5 respondents (0.5%) whose gender was not reported. The mean age of the participants was 32.3 ± 8.8 years. The average number of years of experience as a physiotherapist was 9.5 ± 7.6 years. Regarding educational level, 68.1% of participants had graduated from a specialized training college, 23.9% from a four-year college, and 8.0% held a master’s or doctoral degree. The distribution of job positions was as follows: 69.5% general staff/others, 23.0% unit chiefs/team leaders, 2.2% section chiefs, and 5.3% executive level (Table 1). Factor analysis of the Professional Identity Scale for Physiotherapists Exploratory factor analysis resulted in items 5, 8, 10, 13, 15, 18, 20, 21, and 31 being excluded from the original 37 items, leading to 28 items being extracted (Table 2). A five-factor structure was deemed appropriate based on scree plot criteria. Sample adequacy was confirmed with a Kaiser-Meyer-Olkin measure of 0.96 and Bartlett’s sphericity test ( p < 0.001). The cumulative contribution rate of the five factors was 63.91%. As a result of applying factor extraction using the five factors that were determined, Factor 1 contained 8 items (α = 0.92), Factor 2 contained 7 items (α = 0.92), Factor 3 contained 5 items (α = 0.87), Factor 4 contained 3 items (α = 0.85), and Factor 5 contained 5 items (α = 0.91). Cronbach’s α for the overall scale was 0.96, indicating high reliability. The numbering and labelling of factors in the revised version have been changed due to item reductions and content revisions. Items 5, 10, and 21, which were originally part of the second factor (Professional Perspective) in the 37-item version, were deleted during the revision process. Item 31, which had previously belonged to the third factor (Practical Skills), was excluded during the refinement process, although this factor is now labeled as the second factor in the final scale. Item 13, formerly associated with the fourth factor (Sense of Adaptability), was also excluded due to low factor loading. In addition, Items 8, 15, 18, and 20 had originally belonged to the fifth factor (Orientation Toward Contributing to Interprofessional Collaboration) but were excluded due to cross-loadings or weak associations in the updated factor structure. Criterion-related validity Table 3 presents the results of Spearman’s rank correlation coefficients between the total score and five factors of the revised Professional Identity Scale for Physiotherapists and the three subscales of the Japanese version of the Burnout Scale. The total score was negatively correlated with emotional exhaustion ( r = -0.322, p < 0.001) and depersonalization ( r = -0.281, p < 0.001) but positively correlated with personal accomplishment ( r = 0.498, p < 0.001). In addition, a corresponding trend was observed in the correlation between each factor and the burnout subscales. Discussion This study evaluated the reliability and validity of the revised Professional Identity Scale for Physiotherapists. The revised 28-item scale, comprising five factors, demonstrated sufficient reliability and validity and may serve as a practical tool for assessing the professional identity of physiotherapists. The first factor, “Development of and Contribution to the Professional Group,” reflects physiotherapists’ aspirations for professional growth and their contributions to the field, such as mentoring and career advancement. It also encompasses pride in the profession and a desire for personal and professional development. Given its high cumulative contribution rate (47.11%), this factor can be interpreted as a core element of physiotherapists’ professional identity. This element aligns with the ethical guidelines of the Japanese Physical Therapy Association, which emphasize responsibilities related to education, training, and professional development [ 21 ]. Joseph et al. [ 22 ] highlighted that mentoring junior professionals is essential to professionalism, while Hammond et al. [ 9 ] noted that a well-developed sense of professionalism enhances beliefs, values, and knowledge, thereby strengthening professional identity. Furthermore, the importance of professionalism and mentoring has been widely recognized [ 23 ], suggesting that opportunities to support the development of future professionals play a crucial role in shaping professional identity. Similar factors are also found in professional identity scales for other occupations, including occupational therapists [ 16 ], nurses [ 24 ], and physicians [ 25 ]. From these perspectives, fulfilling professional responsibilities—such as mentoring and contributing to the growth of the profession—can be considered fundamental components in the formation of professional identity. The second factor, “Practical Skills,” consists of seven items: observation and analysis, problem-solving, evidence-based physiotherapy, risk management, preventive physiotherapy, clear explanations, and interpersonal skills. These items represent key aspects of the practical competencies that characterize the professional roles of physiotherapists. They are consistent with prior qualitative findings that highlight the importance of applying specialized knowledge, analyzing movement, planning individualized interventions, and communicating effectively in clinical practice [ 26 ]. Previous research has also emphasized that these practical abilities are essential for clinical reasoning and the delivery of patient-centered care. The third factor, “Client-Centered Support,” captures physiotherapists’ commitment to respectful, empathetic, and collaborative engagement with their clients. In the original 37-item scale, this factor included items related to self-awareness and professional growth, such as having one’s own perspective on physiotherapy, personal development through work, and the desire to contribute to society [ 17 ]. Based on these contents, it was initially labeled “Professional Perspective.” However, these items were excluded during the refinement process due to low factor loadings or conceptual overlap. The revised factor comprises items that emphasize respect for the individuality of clients, support for their autonomy, shared goal setting, and sensitivity to subtle changes in their condition. These elements consistently reflect physiotherapists’ intention to support clients in a holistic and collaborative manner. Accordingly, the factor was renamed “Client-Centered Support” to more accurately reflect its content. This domain is particularly noteworthy because such a focus on direct client support has not been explicitly identified in previous professional identity scales for other healthcare professions. Thus, the emergence of this factor suggests that client-centeredness represents a distinctive and meaningful component of professional identity in physiotherapists, offering a novel perspective that enriches the conceptual understanding of professional identity in the field. The fourth factor, “Sense of Adaptability,” reflects a physiotherapist’s perception of alignment between their professional role and personal identity. This factor highlights the importance of perceiving oneself as well-suited to one’s occupation as a key determinant of professional satisfaction. It encompasses a sense of career satisfaction, vitality, and long-term commitment to the profession. The items included—feeling that being a physiotherapist is authentic to oneself, wanting to continue in the profession throughout one’s life, and working with enthusiasm—suggest that this factor captures a positive, internalized sense of fit with the professional role. This concept is consistent with previous research on healthcare professionals, which has emphasized that perceiving one’s occupation as congruent with personal values contributes to motivation, resilience, and professional fulfillment [ 3 , 15 ]. While themes of self-occupation congruence have been conceptually addressed and sometimes incorporated into professional identity scales, the emergence of this factor in the current study reinforces its relevance for physiotherapists and highlights its importance as a distinct dimension of professional identity. The fifth factor, “Orientation Toward Contributing to Interprofessional Collaboration,” emphasizes the role of physiotherapists in teamwork and their expertise within interprofessional collaboration. This factor reflects the ethical responsibility to cooperate with other healthcare professionals to achieve optimal patient outcomes, consistent with the Code of Ethics of the Japan Physical Therapy Association [ 21 ]. Notably, items related to interprofessional collaboration do not typically appear in professional identity scales for nurses or physicians, whereas such items are included in scales for occupational therapists [ 16 ]. This suggests that the emphasis on interprofessional collaboration may represent a characteristic element of professional identity unique to rehabilitation professions. Moreover, qualitative studies examining the professional characteristics of physiotherapists have also highlighted interprofessional collaboration as a distinctive aspect, further supporting the idea that this factor reflects a rehabilitation-specific dimension of professional identity [ 27 ]. The relationship between professional identity and burnout showed a strong negative correlation with emotional exhaustion and depersonalization but a positive correlation with personal accomplishment. These findings suggest that higher professional identity may serve as a protective factor against burnout, which is consistent with previous studies in other healthcare professions [ 6 , 26 ]. Particularly, the fourth factor, “Sense of Adaptability,” showed a high correlation with the three subscales (emotional exhaustion : r = -0.493, depersonalization: r = -0.449, personal accomplishment : r = 0.523). This adaptability reflects the perception that one’s profession aligns with personal values and identity. These results suggest that a high sense of professional adjustment may prevent burnout among physiotherapists with professional identity. This study has several limitations. First, the same dataset ( n = 1 037) was used for both the item reduction process (driven by exploratory factor analysis) and the establishment of the final 28-item factor structure. Best practice in scale development often involves splitting a sample or using an independent sample for validation. Using a single dataset carries a risk of overfitting the model to the specific characteristics of our sample, which may limit the generalizability of the findings. Therefore, the five factors presented in this study should be considered promising but preliminary. To robustly establish the scale’s structural validity, future research must conduct a confirmatory factor analysis on a new, independent sample of physiotherapists. Second, all participants were physiotherapists practicing in Japan, and the scale may reflect cultural and professional norms specific to Japanese clinical settings. Therefore, caution is required when generalizing the findings to physiotherapists in other countries. Further validation using international samples is needed to assess the cross-cultural applicability of the scale. Third, this study employed a snowball sampling approach using professional networks to recruit participants. Although this method facilitated nationwide data collection, the sample may not fully represent the entire population of physiotherapists in Japan (approximately 142 500 licensed physiotherapists nationwide [ 28 ]). In particular, snowball sampling may introduce selection bias, as participants are more likely to be recruited from specific professional or social networks. Therefore, caution is warranted when generalizing the findings. Finally, although this study examined predictive validity using the Japanese version of the Burnout Scale, it would be desirable to further validate the scale by examining its relationships with additional factors such as occupational competence, job satisfaction, and work engagement. Conclusions The revised scale is a reliable and valid tool for assessing professional identity among Japanese physiotherapists. Its application can support educational planning, career development, and organizational strategies aimed at strengthening professional identity. Incorporating the scale into training and professional development programs may enhance job satisfaction, motivation, and resilience among physiotherapists. Future studies should explore the scale’s utility in diverse contexts and examine factors influencing professional identity formation. Declarations Reporting guidelines: This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for reporting cross-sectional studies. In addition, the development and validation of the Professional Identity Scale for Physiotherapists were conducted in accordance with the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) checklist for measurement properties. Data availability: The datasets generated and/or analyzed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request. Ethics approval and consent to participate This study was approved by the Ethical Review Committee of the International University of Health and Welfare (Approval No. 22-Ifh-047). All participants provided informed consent prior to completing the web-based questionnaire. Participation was voluntary, and all responses were anonymous. Consent for publication Not applicable. No identifiable personal data are included in this study. Availability of data and materials The datasets generated and/or analysed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Authors' contributions KN and TS drafted the main manuscript. MI, TI, AS, and NM contributed to the study design, data analysis, and interpretation. YH supervised the entire study and provided critical revisions. All authors reviewed and approved the final manuscript. Acknowledgements The authors would like to express their sincere appreciation to all physiotherapists who generously participated in the nationwide survey. We also extend our gratitude to the expert panel members who provided valuable insights during the item refinement process, as well as to the institutions that facilitated survey distribution. Their contributions were essential to the development and validation of the revised Professional Identity Scale for Physiotherapists. References ABIM Foundation, ACP-ASIM Foundation, European Federation of Internal Medicine. Medical professionalism in the new millennium: a physician charter. Ann Intern Med 2002;136(3):243–6. https://doi.org/10.7326/0003-4819-136-3-200202050-00012 American Physical Therapy Association. 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Tables Tables 1 to 3 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Table1.xlsx Table2.xlsx Table3.xlsx STROBEchecklist.docx SupplementaryA.docx Appendix A. Supporting information The 28-item Professional Identity Scale for Physiotherapists (PISP-28). SupplementaryB.docx Appendix B. Supporting information Supplementary Figure 1. Flowchart of study participants. Supplementary Figure 2. Flowchart of the scale development process for the 28-item Professional Identity Scale for Physiotherapists (PISP-28). Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8260003","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":587083414,"identity":"30d57d55-bcea-46ad-ac63-3bc6c6c1bc51","order_by":0,"name":"Kayoko 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Saito","email":"","orcid":"","institution":"Reiwa Health Sciences University","correspondingAuthor":false,"prefix":"","firstName":"Takafumi","middleName":"","lastName":"Saito","suffix":""},{"id":587083424,"identity":"fcaf9abb-8809-4aee-8ab8-2a401bb0ccaa","order_by":3,"name":"Takuro Ikeda","email":"","orcid":"","institution":"Fukuoka International University of Health and Welfare","correspondingAuthor":false,"prefix":"","firstName":"Takuro","middleName":"","lastName":"Ikeda","suffix":""},{"id":587083426,"identity":"0adf2731-33b0-4bc2-8bb9-d88b74271b6b","order_by":4,"name":"Akihiro Shimiya","email":"","orcid":"","institution":"Tomei Atsugi Hospital","correspondingAuthor":false,"prefix":"","firstName":"Akihiro","middleName":"","lastName":"Shimiya","suffix":""},{"id":587083430,"identity":"4106392a-751e-444b-9078-9512b5870e53","order_by":5,"name":"Norihisa Matsukawa","email":"","orcid":"","institution":"Sakai City Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Norihisa","middleName":"","lastName":"Matsukawa","suffix":""},{"id":587083432,"identity":"1aee016d-7936-427b-b80e-e1f083be5d5a","order_by":6,"name":"Yukari Horimoto","email":"","orcid":"","institution":"International University of Health and Welfare","correspondingAuthor":false,"prefix":"","firstName":"Yukari","middleName":"","lastName":"Horimoto","suffix":""}],"badges":[],"createdAt":"2025-12-02 11:38:29","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8260003/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8260003/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108806318,"identity":"b5a30863-1370-4097-8d1d-3ac669787675","added_by":"auto","created_at":"2026-05-08 15:28:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":215461,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/62f42bd5-9983-4baa-a362-4ccff5c796c2.pdf"},{"id":102229172,"identity":"1703854f-c415-48d4-855a-b82c2026543b","added_by":"auto","created_at":"2026-02-09 15:12:44","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":10143,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/62339663c7411aa82509303f.xlsx"},{"id":102229298,"identity":"f6776d1f-3472-435c-b37a-6a9f0cc337e6","added_by":"auto","created_at":"2026-02-09 15:13:01","extension":"xlsx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":13712,"visible":true,"origin":"","legend":"","description":"","filename":"Table2.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/cd4c7d78c7b59d8a8fb220da.xlsx"},{"id":102229141,"identity":"0b3211ec-8720-4659-9487-b2addf2a3945","added_by":"auto","created_at":"2026-02-09 15:12:40","extension":"xlsx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":10335,"visible":true,"origin":"","legend":"","description":"","filename":"Table3.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/55b9f2c6e954d6a2a76ffed7.xlsx"},{"id":102229236,"identity":"ee549fcc-1cbe-4866-9af8-03c12725b023","added_by":"auto","created_at":"2026-02-09 15:12:54","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":41212,"visible":true,"origin":"","legend":"","description":"","filename":"STROBEchecklist.docx","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/7f39fa7f2ae1f7614c15716a.docx"},{"id":102229193,"identity":"1ae23faa-f4b3-4099-ac78-a54bf1462ef8","added_by":"auto","created_at":"2026-02-09 15:12:46","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":18602,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAppendix A. Supporting information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe 28-item Professional Identity Scale for Physiotherapists (PISP-28).\u003c/p\u003e","description":"","filename":"SupplementaryA.docx","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/8b023be0e2fa7f56518a6cba.docx"},{"id":102229216,"identity":"25d3be4a-b4fb-4a7c-9904-4c59599ee102","added_by":"auto","created_at":"2026-02-09 15:12:49","extension":"docx","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":30752,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAppendix B. Supporting information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSupplementary Figure 1. Flowchart of study participants.\u003c/p\u003e\n\u003cp\u003eSupplementary Figure 2. Flowchart of the scale development process for the 28-item Professional Identity Scale for Physiotherapists (PISP-28).\u003c/p\u003e","description":"","filename":"SupplementaryB.docx","url":"https://assets-eu.researchsquare.com/files/rs-8260003/v1/b2103a3fc042aa1c63afca9a.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Identifying core elements of professional identity among Japanese physiotherapists: a scale revision and validation","fulltext":[{"header":"Contribution of the Paper","content":"\u003cul\u003e\n \u003cli\u003eThis study developed a revised version of the professional identity scale tailored for physiotherapists in Japan, improving its clarity, structure, and psychometric properties.\u003c/li\u003e\n \u003cli\u003eExploratory factor analysis identified a robust five-factor structure with high internal consistency, providing a clear conceptual framework for understanding professional identity in physiotherapists.\u003c/li\u003e\n \u003cli\u003eDemonstration of criterion-related validity through significant correlations with burnout dimensions, highlighting potential utility in identifying professionals at risk of burnout and informing interventions.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Introduction","content":"\u003cp\u003eProfessionalism refers to the external expectations placed on professionals, including codes of conduct, ethical standards, appropriate behaviors, attitudes, and relationships required in the practice of a profession [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. The American Physical Therapy Association identifies seven core values that constitute professionalism in physiotherapists: accountability, altruism, compassion, excellence, integrity, professional duty, and social responsibility [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhile professionalism reflects externally endorsed standards and expectations, professional identity involves the internalization of these values. It is defined as an individual\u0026rsquo;s understanding and acceptance of the beliefs, values, attitudes, and roles associated with their professional group [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In this sense, professional identity captures how individuals perceive themselves as professionals, moving beyond external norms to construct an internal sense of professional self.\u003c/p\u003e \u003cp\u003eUnderstanding professional norms and adopting core values are essential in developing a professional identity [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. In addition, professionalism and professional identity are closely linked, with the latter enhanced through educational efforts that promote professional values. Individuals with a strong professional identity tend to exhibit higher stress tolerance and are less susceptible to burnout, indicating the need to focus on education that enhances professional identity [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSince the early 2000s, research on professional identity has grown [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. However, a scoping review revealed limited focus on rehabilitation professionals, with only 19% (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;10) of studies addressing physiotherapists [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Among these, only two studies [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] examined practicing physiotherapists, emphasizing the role of professional socialization, while the others focused on students [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRegarding research on healthcare professional identity in Japan, most scale development efforts have focused on nurses, with only three studies addressing occupational therapists [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Notably, there are still few reliable and valid scales specifically designed to assess the professional identity of physiotherapists [\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAn exception is Nonaka et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] who developed a professional identity scale specifically for physiotherapists in Japan, reflecting their occupational values, roles, and interprofessional collaboration within Japanese clinical contexts. This 37-item measure was developed through a literature review and expert consensus and demonstrated high reliability and a clear factor structure. However, to enhance its practical utility in clinical settings, the scale must be refined into a more concise and practical form. Accordingly, following the guidelines proposed by DeVellis [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], we combined statistical criteria\u0026mdash;such as factor loadings and cross-loadings\u0026mdash;with expert review to ensure both content validity and conceptual clarity.\u003c/p\u003e \u003cp\u003eThis study evaluates the reliability and validity of the revised version of the Professional Identity Scale for Physiotherapists. Given the limited international research on professional identity among physiotherapists, this newly developed instrument represents a novel contribution to the field and is expected to serve as a valuable tool for both educational and research purposes, in Japan and beyond.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThe dataset was obtained from a questionnaire survey originally conducted to develop the initial version of the scale [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. We adopted a snowball sampling approach using professional networks to recruit participants, and data were collected via a web-based questionnaire (Google Forms) between June 1 and September 30, 2023.\u003c/p\u003e \u003cp\u003eMost widely accepted guidelines for factor analysis generally consider a minimum of 200\u0026ndash;300 participants as necessary to obtain stable factor solutions [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. To ensure stable factor loadings and a reliable psychometric evaluation, we set our target sample size at 500 participants. The survey was distributed to 499 institutions nationwide that employ physiotherapists, and ultimately, valid responses were obtained from 1 037 physiotherapists, exceeding the recommended threshold. As the web-based questionnaire required responses to all items before submission, no missing data were generated.\u003c/p\u003e \u003cp\u003eThe questionnaire included the following components: gender, age, years of clinical experience, final educational level (specialized training college, four-year college, master\u0026rsquo;s or doctoral degree), job position (general staff/others, unit chief/team leader, section chief, executive level), the initial version of the Professional Identity Scale for Physiotherapists [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], and the Japanese version of the Burnout Scale [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eProfessional Identity Scale for Physiotherapists\u003c/h2\u003e \u003cp\u003eThe preliminary psychometric properties of the original 37-item Professional Identity Scale for Physiotherapists have already been reported in [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Given that the original publication is in Japanese, we briefly outline the development process here for the benefit of international readers.\u003c/p\u003e \u003cp\u003eA scale to assess the professional identity of physiotherapists was developed and validated through a three-phase process. In the first phase, focus group interviews were conducted with 13 physiotherapists working in clinical and educational settings. Through these interviews, an initial pool of 50 items was generated and subsequently refined. Based on expert reviews, 10 items were deleted, resulting in a provisional 40-item version.\u003c/p\u003e \u003cp\u003eIn the second phase, a preliminary survey was conducted with 186 physiotherapists to examine the scale\u0026rsquo;s reliability and factor structure. Based on item-total correlation analysis, 3 items were removed, resulting in a 37-item version. Exploratory factor analysis identified a four-factor structure; Cronbach\u0026rsquo;s α was 0.95 for the total scale and between 0.81 to 0.90 for the four subscales. Notably, during this preliminary stage, the authors prioritized comprehensive content coverage over strict statistical criteria, resulting in a 37-item version that included some items with factor loadings below 0.4 or with cross-loadings. The goal was to ensure that the initial scale comprehensively captured the full range of professional identity concepts identified in their qualitative research.\u003c/p\u003e \u003cp\u003eIn the third phase, a large-scale web-based survey was conducted with 1 037 physiotherapists to further validate the scale. Exploratory factor analysis using the scree plot criterion confirmed a five-factor structure. The cumulative variance explained by these five factors was 62.62%. The five factors were: \u003cem\u003eDevelopment of and Contribution to the Professional Group\u003c/em\u003e (8 items), \u003cem\u003eProfessional Perspective\u003c/em\u003e (8 items), \u003cem\u003ePractical Skills\u003c/em\u003e (8 items), \u003cem\u003eSense of Adaptability\u003c/em\u003e (4 items), and \u003cem\u003eOrientation Toward Contributing to Interprofessional Collaboration\u003c/em\u003e (9 items). The factor labels were determined by consensus among a panel of 10 expert physiotherapists with more than 10 years of clinical experience. Cronbach\u0026rsquo;s α was 0.97 for the total scale and between 0.85 to 0.94 for the five subscales, indicating high internal consistency.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eJapanese version of the Burnout Scale\u003c/h3\u003e\n\u003cp\u003eTo assess criterion-related validity, the scale was compared with the Japanese version of the Burnout Scale, which comprises three independent subscales: emotional exhaustion\u0026mdash;psychological fatigue and feelings of being emotionally drained, depersonalization\u0026mdash;detachment or indifference toward others (e.g., avoiding bothersome interpersonal interactions), and personal accomplishment\u0026mdash;a sense of competence and successful achievement in one\u0026rsquo;s work. Each subscale is measured using a 5-point Likert scale from 1 (\u003cem\u003enever\u003c/em\u003e) to 5 (\u003cem\u003ealways\u003c/em\u003e) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eStatistical analyses\u003c/h3\u003e\n\u003cp\u003eWe conducted an item reduction process to develop a revised version of the original 37-item Professional Identity Scale for Physiotherapists based on the criteria of both statistical and content validity. Specifically, exploratory factor analysis was employed to assess the factor structure, and items with factor loadings below 0.4 or cross-loadings exceeding 0.3 were excluded. Content validity was assessed by an expert panel, leading to the removal of items that were conceptually ambiguous or redundant. This process was carried out in accordance with the guidelines proposed by DeVellis [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e], who emphasizes that item selection should be guided by both statistical indicators and expert judgment to ensure content validity and conceptual clarity.\u003c/p\u003e \u003cp\u003eWe conducted exploratory factor analysis using the revised version of the scale. The maximum likelihood estimation method with promax rotation was used for factor extraction, and the number of factors was determined based on the scree plot. Sample adequacy was verified using the Kaiser-Meyer-Olkin test and Bartlett\u0026rsquo;s test of sphericity. Items were selected based on eigenvalues\u0026thinsp;\u0026ge;\u0026thinsp;1, factor loadings\u0026thinsp;\u0026ge;\u0026thinsp;0.4, and minimal cross-loading (loadings\u0026thinsp;\u0026lt;\u0026thinsp;0.3 on other factors). Cronbach\u0026rsquo;s α coefficients were calculated to assess internal consistency. Criterion-related validity was evaluated by Spearman\u0026rsquo;s rank correlation coefficient between the total score and five factors of the revised version of the Professional Identity Scale for Physiotherapists and the three subscales of the Japanese version of the Burnout Scale. A panel of 10 experienced physiotherapists, each with more than 10 years of clinical experience, interpreted the factor analysis results and named the factors through consensus. Statistical analyses were performed using IBM SPSS Statistics for Windows version 29. The statistical significance was defined as a 2-tailed p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eParticipant characteristics\u003c/h2\u003e \u003cp\u003eA total of 1 037 valid responses were included in the analysis. The sample consisted of 710 males (68.5%), 322 females (31.0%), and 5 respondents (0.5%) whose gender was not reported. The mean age of the participants was 32.3\u0026thinsp;\u0026plusmn;\u0026thinsp;8.8 years. The average number of years of experience as a physiotherapist was 9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6 years. Regarding educational level, 68.1% of participants had graduated from a specialized training college, 23.9% from a four-year college, and 8.0% held a master\u0026rsquo;s or doctoral degree. The distribution of job positions was as follows: 69.5% general staff/others, 23.0% unit chiefs/team leaders, 2.2% section chiefs, and 5.3% executive level (Table\u0026nbsp;1).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eFactor analysis of the Professional Identity Scale for Physiotherapists\u003c/h2\u003e \u003cp\u003eExploratory factor analysis resulted in items 5, 8, 10, 13, 15, 18, 20, 21, and 31 being excluded from the original 37 items, leading to 28 items being extracted (Table\u0026nbsp;2). A five-factor structure was deemed appropriate based on scree plot criteria. Sample adequacy was confirmed with a Kaiser-Meyer-Olkin measure of 0.96 and Bartlett\u0026rsquo;s sphericity test (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The cumulative contribution rate of the five factors was 63.91%.\u003c/p\u003e \u003cp\u003eAs a result of applying factor extraction using the five factors that were determined, Factor 1 contained 8 items (α\u0026thinsp;=\u0026thinsp;0.92), Factor 2 contained 7 items (α\u0026thinsp;=\u0026thinsp;0.92), Factor 3 contained 5 items (α\u0026thinsp;=\u0026thinsp;0.87), Factor 4 contained 3 items (α\u0026thinsp;=\u0026thinsp;0.85), and Factor 5 contained 5 items (α\u0026thinsp;=\u0026thinsp;0.91). Cronbach\u0026rsquo;s α for the overall scale was 0.96, indicating high reliability.\u003c/p\u003e \u003cp\u003eThe numbering and labelling of factors in the revised version have been changed due to item reductions and content revisions. Items 5, 10, and 21, which were originally part of the second factor (Professional Perspective) in the 37-item version, were deleted during the revision process. Item 31, which had previously belonged to the third factor (Practical Skills), was excluded during the refinement process, although this factor is now labeled as the second factor in the final scale. Item 13, formerly associated with the fourth factor (Sense of Adaptability), was also excluded due to low factor loading. In addition, Items 8, 15, 18, and 20 had originally belonged to the fifth factor (Orientation Toward Contributing to Interprofessional Collaboration) but were excluded due to cross-loadings or weak associations in the updated factor structure.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eCriterion-related validity\u003c/h3\u003e\n\u003cp\u003eTable\u0026nbsp;3 presents the results of Spearman\u0026rsquo;s rank correlation coefficients between the total score and five factors of the revised Professional Identity Scale for Physiotherapists and the three subscales of the Japanese version of the Burnout Scale. The total score was negatively correlated with emotional exhaustion (\u003cem\u003er\u003c/em\u003e = -0.322, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and depersonalization (\u003cem\u003er\u003c/em\u003e = -0.281, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) but positively correlated with personal accomplishment (\u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.498, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In addition, a corresponding trend was observed in the correlation between each factor and the burnout subscales.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study evaluated the reliability and validity of the revised Professional Identity Scale for Physiotherapists. The revised 28-item scale, comprising five factors, demonstrated sufficient reliability and validity and may serve as a practical tool for assessing the professional identity of physiotherapists.\u003c/p\u003e \u003cp\u003eThe first factor, \u0026ldquo;Development of and Contribution to the Professional Group,\u0026rdquo; reflects physiotherapists\u0026rsquo; aspirations for professional growth and their contributions to the field, such as mentoring and career advancement. It also encompasses pride in the profession and a desire for personal and professional development. Given its high cumulative contribution rate (47.11%), this factor can be interpreted as a core element of physiotherapists\u0026rsquo; professional identity. This element aligns with the ethical guidelines of the Japanese Physical Therapy Association, which emphasize responsibilities related to education, training, and professional development [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Joseph et al. [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] highlighted that mentoring junior professionals is essential to professionalism, while Hammond et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] noted that a well-developed sense of professionalism enhances beliefs, values, and knowledge, thereby strengthening professional identity. Furthermore, the importance of professionalism and mentoring has been widely recognized [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e], suggesting that opportunities to support the development of future professionals play a crucial role in shaping professional identity. Similar factors are also found in professional identity scales for other occupations, including occupational therapists [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], nurses [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e], and physicians [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. From these perspectives, fulfilling professional responsibilities\u0026mdash;such as mentoring and contributing to the growth of the profession\u0026mdash;can be considered fundamental components in the formation of professional identity.\u003c/p\u003e \u003cp\u003eThe second factor, \u0026ldquo;Practical Skills,\u0026rdquo; consists of seven items: observation and analysis, problem-solving, evidence-based physiotherapy, risk management, preventive physiotherapy, clear explanations, and interpersonal skills. These items represent key aspects of the practical competencies that characterize the professional roles of physiotherapists. They are consistent with prior qualitative findings that highlight the importance of applying specialized knowledge, analyzing movement, planning individualized interventions, and communicating effectively in clinical practice [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Previous research has also emphasized that these practical abilities are essential for clinical reasoning and the delivery of patient-centered care.\u003c/p\u003e \u003cp\u003eThe third factor, \u0026ldquo;Client-Centered Support,\u0026rdquo; captures physiotherapists\u0026rsquo; commitment to respectful, empathetic, and collaborative engagement with their clients. In the original 37-item scale, this factor included items related to self-awareness and professional growth, such as having one\u0026rsquo;s own perspective on physiotherapy, personal development through work, and the desire to contribute to society [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Based on these contents, it was initially labeled \u0026ldquo;Professional Perspective.\u0026rdquo; However, these items were excluded during the refinement process due to low factor loadings or conceptual overlap. The revised factor comprises items that emphasize respect for the individuality of clients, support for their autonomy, shared goal setting, and sensitivity to subtle changes in their condition. These elements consistently reflect physiotherapists\u0026rsquo; intention to support clients in a holistic and collaborative manner. Accordingly, the factor was renamed \u0026ldquo;Client-Centered Support\u0026rdquo; to more accurately reflect its content. This domain is particularly noteworthy because such a focus on direct client support has not been explicitly identified in previous professional identity scales for other healthcare professions. Thus, the emergence of this factor suggests that client-centeredness represents a distinctive and meaningful component of professional identity in physiotherapists, offering a novel perspective that enriches the conceptual understanding of professional identity in the field.\u003c/p\u003e \u003cp\u003eThe fourth factor, \u0026ldquo;Sense of Adaptability,\u0026rdquo; reflects a physiotherapist\u0026rsquo;s perception of alignment between their professional role and personal identity. This factor highlights the importance of perceiving oneself as well-suited to one\u0026rsquo;s occupation as a key determinant of professional satisfaction. It encompasses a sense of career satisfaction, vitality, and long-term commitment to the profession. The items included\u0026mdash;feeling that being a physiotherapist is authentic to oneself, wanting to continue in the profession throughout one\u0026rsquo;s life, and working with enthusiasm\u0026mdash;suggest that this factor captures a positive, internalized sense of fit with the professional role. This concept is consistent with previous research on healthcare professionals, which has emphasized that perceiving one\u0026rsquo;s occupation as congruent with personal values contributes to motivation, resilience, and professional fulfillment [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. While themes of self-occupation congruence have been conceptually addressed and sometimes incorporated into professional identity scales, the emergence of this factor in the current study reinforces its relevance for physiotherapists and highlights its importance as a distinct dimension of professional identity.\u003c/p\u003e \u003cp\u003eThe fifth factor, \u0026ldquo;Orientation Toward Contributing to Interprofessional Collaboration,\u0026rdquo; emphasizes the role of physiotherapists in teamwork and their expertise within interprofessional collaboration. This factor reflects the ethical responsibility to cooperate with other healthcare professionals to achieve optimal patient outcomes, consistent with the Code of Ethics of the Japan Physical Therapy Association [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Notably, items related to interprofessional collaboration do not typically appear in professional identity scales for nurses or physicians, whereas such items are included in scales for occupational therapists [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. This suggests that the emphasis on interprofessional collaboration may represent a characteristic element of professional identity unique to rehabilitation professions. Moreover, qualitative studies examining the professional characteristics of physiotherapists have also highlighted interprofessional collaboration as a distinctive aspect, further supporting the idea that this factor reflects a rehabilitation-specific dimension of professional identity [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe relationship between professional identity and burnout showed a strong negative correlation with emotional exhaustion and depersonalization but a positive correlation with personal accomplishment. These findings suggest that higher professional identity may serve as a protective factor against burnout, which is consistent with previous studies in other healthcare professions [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Particularly, the fourth factor, \u0026ldquo;Sense of Adaptability,\u0026rdquo; showed a high correlation with the three subscales (emotional exhaustion : \u003cem\u003er\u003c/em\u003e = -0.493, depersonalization: \u003cem\u003er\u003c/em\u003e = -0.449, personal accomplishment : \u003cem\u003er\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.523). This adaptability reflects the perception that one\u0026rsquo;s profession aligns with personal values and identity. These results suggest that a high sense of professional adjustment may prevent burnout among physiotherapists with professional identity.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, the same dataset (\u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1 037) was used for both the item reduction process (driven by exploratory factor analysis) and the establishment of the final 28-item factor structure. Best practice in scale development often involves splitting a sample or using an independent sample for validation. Using a single dataset carries a risk of overfitting the model to the specific characteristics of our sample, which may limit the generalizability of the findings. Therefore, the five factors presented in this study should be considered promising but preliminary. To robustly establish the scale\u0026rsquo;s structural validity, future research must conduct a confirmatory factor analysis on a new, independent sample of physiotherapists. Second, all participants were physiotherapists practicing in Japan, and the scale may reflect cultural and professional norms specific to Japanese clinical settings. Therefore, caution is required when generalizing the findings to physiotherapists in other countries. Further validation using international samples is needed to assess the cross-cultural applicability of the scale. Third, this study employed a snowball sampling approach using professional networks to recruit participants. Although this method facilitated nationwide data collection, the sample may not fully represent the entire population of physiotherapists in Japan (approximately 142 500 licensed physiotherapists nationwide [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]). In particular, snowball sampling may introduce selection bias, as participants are more likely to be recruited from specific professional or social networks. Therefore, caution is warranted when generalizing the findings. Finally, although this study examined predictive validity using the Japanese version of the Burnout Scale, it would be desirable to further validate the scale by examining its relationships with additional factors such as occupational competence, job satisfaction, and work engagement.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe revised scale is a reliable and valid tool for assessing professional identity among Japanese physiotherapists. Its application can support educational planning, career development, and organizational strategies aimed at strengthening professional identity. Incorporating the scale into training and professional development programs may enhance job satisfaction, motivation, and resilience among physiotherapists. Future studies should explore the scale\u0026rsquo;s utility in diverse contexts and examine factors influencing professional identity formation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eReporting guidelines:\u0026nbsp;\u003c/strong\u003eThis study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines for reporting cross-sectional studies. In addition, the development and validation of the Professional Identity Scale for Physiotherapists were conducted in accordance with the COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) checklist for measurement properties.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability:\u0026nbsp;\u003c/strong\u003eThe datasets generated and/or analyzed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethical Review Committee of the International University of Health and Welfare (Approval No. 22-Ifh-047). All participants provided informed consent prior to completing the web-based questionnaire. Participation was voluntary, and all responses were anonymous.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable. No identifiable personal data are included in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available due to privacy and ethical restrictions but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKN and TS drafted the main manuscript. MI, TI, AS, and NM contributed to the study design, data analysis, and interpretation. YH supervised the entire study and provided critical revisions. All authors reviewed and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to express their sincere appreciation to all physiotherapists who generously participated in the nationwide survey. We also extend our gratitude to the expert panel members who provided valuable insights during the item refinement process, as well as to the institutions that facilitated survey distribution. Their contributions were essential to the development and validation of the revised Professional Identity Scale for Physiotherapists.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eABIM Foundation, ACP-ASIM Foundation, European Federation of Internal Medicine. Medical professionalism in the new millennium: a physician charter. Ann Intern Med 2002;136(3):243\u0026ndash;6. https://doi.org/10.7326/0003-4819-136-3-200202050-00012\u003c/li\u003e\n\u003cli\u003eAmerican Physical Therapy Association. Professionalism in physical therapy: core values. Alexandria, VA: American Physical Therapy Association; 2003. Available at: https://www.apta.org/apta-and-you/leadership-and-governance/policies/core-values-for-the-physical-therapist-and-physical-therapist-assistant [Accessed 21 September 2025].\u003c/li\u003e\n\u003cli\u003eAdams K, Hean S, Sturgis P, Clark JM. Investigating the factors influencing professional identity of first-year health and social care students. Learning in Health and Social Care 2006;5(2):55\u0026ndash;68. https://doi.org/10.1111/j.1473-6861.2006.00119.x\u003c/li\u003e\n\u003cli\u003eRees CE, Monrouxe LV. Who are you and who do you want to be? Key considerations in developing professional identities in medicine. Med J Aust 2018;209(5):202\u0026ndash;3. https://doi.org/10.5694/mja18.00118 \u003c/li\u003e\n\u003cli\u003eCruess RL, Cruess SR, Boudreau JD, Snell L, Steinert Y. Reframing medical education to support professional identity formation. Acad Med 2014;89(11):1446\u0026ndash;51. https://doi.org/10.1097/ACM.0000000000000427\u003c/li\u003e\n\u003cli\u003eZhang T, Feng J, Jiang H, Shen X, Pu B, Gan Y. Association of professional identity, job satisfaction and burnout with turnover intention among general practitioners in China: evidence from a national survey. BMC Health Serv Res 2021;21(1):382. https://doi.org/10.1186/s12913-021-06322-6 \u003c/li\u003e\n\u003cli\u003eSabancıogullari S, Dogan S. Effects of the professional identity development programme on the professional identity, job satisfaction and burnout levels of nurses: a pilot study. Int J Nurs Pract 2015;21(6):847\u0026ndash;57. https://doi.org/10.1111/ijn.12330 \u003c/li\u003e\n\u003cli\u003eMak S, Hunt M, Boruff J, Zaccagnini M, Thomas A. Exploring professional identity in rehabilitation professions: a scoping review. Adv Health Sci Educ Theory Pract 2022;27(3):793\u0026ndash;815. https://doi.org/10.1007/s10459-022-10103-z\u003c/li\u003e\n\u003cli\u003eHammond R, Cross V, Moore A. The construction of professional identity by physiotherapists: a qualitative study. Physiotherapy 2016;102(1):71\u0026ndash;7. https://doi. 10.1016/j.physio.2015.04.002 \u003c/li\u003e\n\u003cli\u003eGrafton K. Indian physiotherapists\u0026rsquo; global mobility: a grounded theory journey of professional identity transformation. Doctoral dissertation. Sheffield: Sheffield Hallam University; 2013. Available at: http://shura.shu.ac.uk/10372/\u003c/li\u003e\n\u003cli\u003eHayward LM, Li L. Promoting and assessing cultural competence, professional identity, and advocacy in doctor of physical therapy (DPT) degree students within a community of practice. J Phys Ther Educ 2014;28(1):23\u0026ndash;36. https://doi.10.1097/00001416-201410000-00005\u003c/li\u003e\n\u003cli\u003eLindquist I, Engardt M, Garnham L, Poland F, Richardson B. Physiotherapy students\u0026rsquo; professional identity on the edge of working life. Med Teach 2006;28(3):270\u0026ndash;6. https://doi. 10.1080/01421590600605272\u003c/li\u003e\n\u003cli\u003eKatsura M. A literature review on professional identity in the fields of healthcare, public health, and social welfare. Bulletin of the Faculty of Social Welfare, Kochi Prefectural University 2023;72:73\u0026ndash;88. [in Japanese]\u003c/li\u003e\n\u003cli\u003eLandis T, Barbosa-Leiker C, Clark C, Godfrey N. Professional Identity in Nursing Scale 2.0: a national study of nurses\u0026rsquo; professional identity and psychometric properties. J Prof Nurs 2024;50:61\u0026ndash;5. https://doi.org/10.1016/j.profnurs.2023.11.004\u003c/li\u003e\n\u003cli\u003eSasaki M, Hariu T. Development of the Professional Identity Scale for Nurses (PISN). Journal of Japan Academy of Nursing Science 2006;26:34\u0026ndash;41. [in Japanese]\u003c/li\u003e\n\u003cli\u003eIshikura K. Development of a scale to measure professional identity in occupational therapists. Journal of the Japanese Society for the Study of Occupational Therapy 2020;23(1):1\u0026ndash;8. [in Japanese] \u003c/li\u003e\n\u003cli\u003eNonaka K, Ikeda T, Horimoto Y. Reliability and validity of the Professional Identity Scale for Physiotherapists with 37 items. Physiotherapy Education 2024;4(2):26\u0026ndash;36. [in Japanese]\u003c/li\u003e\n\u003cli\u003eDeVellis RF. Scale development: theory and applications. 4th ed. Thousand Oaks, CA: Sage Publications; 2017.\u003c/li\u003e\n\u003cli\u003eCostello AB, Osborne JW. Best practices in exploratory factor analysis: four recommendations for getting the most from your analysis. Pract Assess Res Eval 2005;10(7):1\u0026ndash;9. https://doi.org/10.7275/jyj1-4868\u003c/li\u003e\n\u003cli\u003eKubo M, Tao M. Measurement of burnout. Japanese Psychological Review 1992;35(3):361\u0026ndash;76. [in Japanese]\u003c/li\u003e\n\u003cli\u003eJapanese Physical Therapy Association. Code of ethics. Tokyo: Japanese Physical Therapy Association; 2022. Available at: https://www.japanpt.or.jp/pt/announcement/pt/ethics/202201CodeofEthics.pdf [Accessed 9 September 2023].\u003c/li\u003e\n\u003cli\u003eJoseph A, Chidozie E, Adetutu O, Oladipo B, Adeyemi T, Olatunji A, et al. Development and evaluation of the readability, stability and internal consistency of a psychometric instrument designed to assess physiotherapists\u0026rsquo; knowledge and attributes of professionalism. Int J Med Health Sci Res 2017;4(6):102\u0026ndash;17. https://doi.org/10.18488/journal.9.2017.46.102.117\u003c/li\u003e\n\u003cli\u003eKrishna LK, Kwok HYF, Ravindran N, Tan XY, Soh J, Wan DWJ, et al. A systematic scoping review of mentoring support on professional identity formation. BMC Med Educ 2024;24(1):1380. https://doi.org/10.1186/s12909-024-06357-3\u003c/li\u003e\n\u003cli\u003eMoola S. Crafting, constructing and developing a Nurses\u0026rsquo; Professional Identity Scale (NPIS). Glob J Health Sci 2017;9(8):21. https://doi.10.5539/gjhs.v9n8p21\u003c/li\u003e\n\u003cli\u003eTagawa M. Development of a scale to evaluate medical professional identity formation. BMC Med Educ 2019;19:63. https://doi.org/10.1186/s12909-019-1499-9\u003c/li\u003e\n\u003cli\u003eNonaka K, Ishino M, Harada S, Yamashita J. Horimoto Y. An exploratory study on professional characteristics of physical therapists using Steps for Coding and Theorization (SCAT). Physiotherapy Education 2024;4(1):38\u0026ndash;57. [in Japanese]\u003c/li\u003e\n\u003cli\u003eEdwards H, Dirette D. The relationship between professional identity and burnout among occupational therapists. Occup Ther Health Care 2010;24(2):119\u0026ndash;29. https://doi.org/10.3109/07380570903329610 \u003c/li\u003e\n\u003cli\u003eJapanese Physical Therapy Association. Statistics of physiotherapists. Tokyo: Japanese Physical Therapy Association; 2025. Available at: https://www.japanpt.or.jp/activity/data/ [Accessed 23 August 2025].\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Professional identity, Physiotherapists, Scale development, Factor analysis, Psychometric properties, Burnout","lastPublishedDoi":"10.21203/rs.3.rs-8260003/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8260003/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives:\u003c/strong\u003e To develop a revised version of the Professional Identity Scale for Physiotherapists and clarify core elements of professional identity among Japanese physiotherapists.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDesign:\u003c/strong\u003e A nationwide cross-sectional web-based survey.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSetting:\u003c/strong\u003e The survey was conducted across 499 institutions employing physiotherapists in Japan.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eParticipants:\u003c/strong\u003e A total of 1\u003cstrong\u003e \u003c/strong\u003e037 physiotherapists participated in the study (mean age = 32.3 years; 68.5% male, 31.0% female, and 0.5% unspecified gender).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMain outcome measures: \u003c/strong\u003ePrimary outcome measures were the factor structure and internal consistency of the newly developed Professional Identity Scale for Physiotherapists. Secondary outcome measure included correlations between this scale and the Burnout Scale to assess criterion-related validity.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Exploratory factor analysis yielded a five-factor structure (“Development of and Contribution to the Professional Group,” “Practical Skills,” “Client-Centered Support,” “Sense of Adaptability,” and “Orientation Toward Contributing to Interprofessional Collaboration”) comprising 28 items, after excluding 9 items from the original 37-item version. Cronbach’s α coefficient ranged from 0.85 to 0.92 for the five factors, with an overall value of 0.96. Criterion-related validity was evidenced by significant correlations with the Burnout Scale: the total identity score was negatively correlated with emotional exhaustion (\u003cem\u003er\u003c/em\u003e = -0.322, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001) and depersonalization (\u003cem\u003er\u003c/em\u003e = -0.281, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001) and positively correlated with personal accomplishment (\u003cem\u003er\u003c/em\u003e = 0.498, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e The revised Professional Identity Scale for Physiotherapists is a reliable and valid instrument for assessing professional identity among physiotherapists. It provides a practical framework for research and educational initiatives aimed at fostering professional identity and mitigating burnout. In addition, the scale may contribute to curriculum development, competency-based training, and international comparative studies focused on professional identity within the health professions.\u003c/p\u003e","manuscriptTitle":"Identifying core elements of professional identity among Japanese physiotherapists: a scale revision and validation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-09 15:12:05","doi":"10.21203/rs.3.rs-8260003/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"af64201a-be31-41d7-aafe-4f2fe1443333","owner":[],"postedDate":"February 9th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-07T09:36:50+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-04T13:36:16+00:00","index":52,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-07T09:40:38+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-09 15:12:05","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8260003","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8260003","identity":"rs-8260003","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}