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The Consumer of Low-cost Fitness Centers in Spain: Longitudinal Analysis of the Profile and Typology of Use
iD
Moisés Grimaldi-Puyana2
iD
Salvador Angosto3
iD
Ainara Bernal-García2
iD
Authors Info & Affiliations
Abstract
Introduction
Since its emergence in 2010, the low-cost business model has experienced one of the greatest growths in recent years in the fitness sector, placing Spain as one of the leading countries in terms of consumer base and business volume. The purpose of this study was to analyse longitudinally the profile and typology of users of low-cost fitness centres in Spain over the past five years (2014-2018).
Methods
A total of 42,867 sports consumers (22,985 women and 19,882 men) from different chains of low-cost fitness centres participated in the study. The analysis focused on demographic variables, usage patterns, and loyalty indicators.
Results
Results show that most users are young, primarily aged between 21 and 30 years. However, there was a notable increase in the number of consumers aged between 41 and 60. On average, users attended the centre twice a week and had a membership duration of one to two years. In terms of loyalty, most users were classified as neutral based on the Net Promoter Score (NPS).
Discussion
The study reveals changes in the profile of low-cost fitness centre users in Spain (2014-2018), with more users aged 41-60, increased usage frequency, and longer retention. While this suggests greater adherence, the NPS decline indicates rising expectations. Findings underscore the need to adjust loyalty and segmentation strategies to enhance user experience in this model.
Conclusion
Low-cost fitness centres in Spain mainly attract young users, though middle-aged participation is rising. Usage is moderately frequent and sustained, while loyalty remains neutral, indicating opportunities to improve retention through targeted strategic enhancements.
1. INTRODUCTION
Sport is a phenomenon of global relevance and a notable aspect of current consumption culture [1], with its economic and social significance continually growing [2]. The practice of physical activity is expanding, and the fitness sector specifically is a rapidly growing industry [3]. This growth is evident in the significant increase in gyms, fitness clubs, and their memberships over the last decade [4].
Fitness centres are service organisations that provide sports activities and sell experiences [5, 6]. Within the highly competitive sports services sector, understanding user behaviours, interests, and needs is crucial [7]. In Spain, the fitness sector saw a membership increase of 3.3% and a 14.19% growth in new openings in 2019 [8]. While European fitness attracted around 7 million new subscribers in 2022, this is still below pre-pandemic levels [9]. The Anuario de Estadísticas Deportivas 2025 [10] shows that 31.2% of people engaging in weekly sports activities choose gyms, with private fitness centres being more popular (21.9%) than public ones (11.1%). This aligns with findings that show a majority of recreational sports participants prefer private gyms [11].
Given the large number of consumers and sports facilities, and their significant economic impact, it is essential to understand the characteristics and behaviour of individuals using these services [12]. Segmenting these groups will enhance understanding of their preferences and facilitate decision-making, both for service marketing and for designing tailored proposals based on their needs [13].
2. THEORETICAL FOUNDATION
2.1. The Low-cost Model in Fitness in Spain
The emergence of the low-cost model in fitness centres stems from two key turning points. On the one hand, the economic crisis that began in late 2007 led to price and cost reductions, increasing competition. On the other hand, the rise in value-added tax (VAT) in 2012 from 8% to 21% prompted a transformation in the fitness sector, driving specialisation and differentiation. Currently, the low-cost model has been the fastest growing in recent years [14], aiming to make fitness accessible to the entire population. This approach seeks to achieve a dual objective: maximising membership volume to boost revenue while minimising both fixed and variable costs to generate profits [15].
Various authors have highlighted the distinctions between different business models in fitness centres [12, 16-18], which can be categorised into five groups: low-cost, public centres, medium-tier centres, premium centres, and personalised studios. Organizations that adopted the low-cost business model based their strategy on (1) cost leadership, allowing them to offer highly affordable prices, (2) market segmentation, targeting a very specific population, (3), an innovative service offering, clearly tailored to their potential audience, (4) a value proposition focused on a high volume of weekly activities and extended operating hours, and (5) a strong emphasis on customer acquisition rather than retention, through continuous promotions and no minimum contract requirements.
These characteristics have had two key effects: increased customer attraction [19] and a larger number of clients who, before the rise of this model, had never been members of fitness centres [20]. According to the EuropeActive & Deloitte report [9], Spain continues to maintain its position as one of the main European powers, consolidating its third place. The total number of users in Spanish gyms has increased, reaching 5.4 million subscribers, surpassing the 4.8 million at the end of 2021, i.e., people who purchase products or use certain sports services for their own use or sale [21].
Due to the progressive expansion in the number of facilities and users, market penetration and turnover, academic literature has reported an increase in research in recent years that seeks to understand more specifically what is happening in the fitness sector [e.g., 14, 22, 23]. Additionally, there is a growing number of sector reports prepared by specialised consultancies [e.g., 8, 24] or by equipment and machinery companies within the industry. These companies obtain data through technological systems integrated into the fitness equipment used by users [16]. Furthermore, some equipment companies collaborate with consultancies by sponsoring studies, such as those conducted by Matrix [25] or Precor [26]. Reports from companies like Les Mills International [27, 28] or Peloton Interactive [29] also contribute to this body of knowledge. However, despite the positive evolution in the practice of physical activity in fitness centres, there is little information on how consumers evolve and what their behaviours are, with one of the biggest problems in the sector being the high turnover of consumers and, therefore, their low loyalty [30].
2.2. Fitness Centres Consumers and the Decisive Variables for Management
The fitness sector in Spain is still nascent and rapidly evolving, adapting to new business and activity proposals, more functional facility designs, and sports equipment with a greater technological presence. However, understanding user typology and characteristics is also essential, as it facilitates grasping their needs and demands, reasons for use and leaving, and overall usage behaviour.
According to a study by Life Fitness [16] in which 255 fitness centre managers and directors participated, recommendations were the main reason for signing up, while lack of time was identified as the main reason for leaving. Several recent studies have shown their concern about customer loyalty and abandonment in fitness centres [23, 31]. Thus, the importance of understanding these reasons stems from users' perceptions of the service, highlighting the critical role of measuring perceived quality within management systems and strategies [32].
Among the variables that have been shown to have a positive influence on consumer loyalty or behavioural intentions in fitness centres, perceived quality, perceived value and satisfaction stand out [33], being the most studied in recent years as antecedents of loyalty. Perceived quality, as defined by Zeithaml [34], is 'the judgment of the consumer on the excellence or superiority of a product/service' (p. 3). Its study is crucial because it is understood to be the precursor to loyalty [35]. For this reason, various studies have analysed the importance of quality in fitness services both in Spain [32, 36] and in other countries such as the United Kingdom [37], Greece [38], Portugal [39], Cyprus [40], Turkey [41], Canada [42], Ecuador or Colombia [1], among others. Regarding value, it is a consequence of perceived quality and has even been considered key in research on management and marketing in sports organisations [43]. Zeithaml [34] defines it as 'the global evaluation that the consumer makes of the usefulness of a product based on the perceptions of what he receives and what he gives' (p. 14). This broader characterisation, understood as a comparison between benefits and sacrifices [44], implies that orienting available resources toward the client can significantly improve customer management. Finally, satisfaction would be the evaluation made regarding a product or service about the fulfilment of needs and expectations [45]. It is therefore considered a primary aspect as it is a post-consumption response or evaluation [46, 47] that has a positive impact on the positive perception of the organization, that is, it facilitates the recommendation of the service to potential clients [48] and on the other hand increases the probability of being considered loyal, thus becoming an antecedent of future behavioural intentions.
However, recently studies have been carried out that included new variables as part of the loyalty chain, such as service convenience [14], service experience [49], emotions [50], or servicescape [51], which indicates the importance of knowledge of consumer behaviour.
The growing and significant concern for understanding and valuing the perception that users have of different sports organisations leads those responsible for these services to seek the opinions of their users to improve their management [52]. Understanding user evaluations is one of the main ways to enhance satisfaction [53], which translates into an increase in loyalty and retention of users [54].
Although there are longitudinal studies such as the Anuario de Estadísticas del Deporte prepared by the Ministerio de Educación, Cultura y Deporte [10] on the profile of physical activity practitioners in general, to date, no work to date has examined the evolution of low-cost fitness centre consumers, despite this being a growing business model. For this reason, the objective of this study has been to longitudinally analyse the profile and behaviour of the consumer of low-cost fitness centres in Spain during the years 2014 to 2018.
3. MATERIALS AND METHODS
A descriptive, longitudinal, non-probabilistic, and convenience study was conducted. For data collection, a self-administered online questionnaire was used during the period from January to February in the years 2014, 2015, 2016, 2017, and 2018. Specifically, in 2014 (n = 1,314), two companies participated with a total of ten facilities; in 2015 (n = 8,462), there were nine companies with a total of 60 facilities; in 2016 (n = 15,820), ten chains participated with 65 facilities; in 2017 (n = 6,903), there were seven companies and a total of 60 facilities; and in 2018 (n = 10,368), the same companies participated, and the total number of facilities was 65. The inclusion criteria of the sample were (i) 18 years old or more and (ii) belonging to the fitness or sports centre considered in the study population. The exclusion criteria applied to determine the final sample of participants were: (i) individuals under 18 years of age, (ii) users who were not affiliated with any of the participating low-cost fitness centre chains during the data collection period, (iii) incomplete questionnaire responses, (iv) duplicate entries identified through consistency checks. As this study was based on anonymised secondary data collected through client management systems and self-administered surveys voluntarily distributed by the fitness centres to their registered users, the researchers did not access any personally identifiable information. Therefore, ethical approval and informed consent were not applicable, in accordance with national and institutional guidelines for observational research using anonymised datasets.
The sample of this study consists of 42,867 participants (22,985 women and 19,882 men) from low-cost fitness centre chains in Spain, of which 77.3% reported having some previous experience in a sports centre, compared to 22.7% who were accessing a sports centre for the first time. Regarding age, 36.2% (n = 15,546) were under 30 years old, 52.1% (n = 22,351) were between 31 and 50 years old, and 11.7% (n = 4,970) were over 50 years old. Very similar percentages were obtained for the age ranges of 21-30 (31.3%) and 31-40 (29.5%), which had the highest participation in the study.
An ad hoc questionnaire was designed with questions related to the demand for physical activity offerings in low-cost fitness centres by subscribers, focusing on consumer characteristics (gender, age, previous experience, length of membership, and frequency of attendance), including a measure of loyalty behaviour (Net Promoter Score, NPS) (Reichheld & Markey, 2011). This scale, used to measure loyalty, has an 11-point Likert-type response format where 0 means that the consumer would not recommend these sports services to another potential consumer, and 10 means that they would recommend them. Responses are grouped into three types of consumers: those who respond between 0 and 6 are called detractors, those who respond 7 or 8 are called neutrals, and those who respond between 9 and 10 are considered promoters. Additionally, a loyalty indicator is established by calculating the total percentage of promoters minus the total percentage of detractors. Appendix 1 shows the items of the variable analysed.
Each year, the fifteen main chains in terms of the number of low-cost fitness centres in Spain were contacted to explain the study's objectives and their potential participation. The sample selection was based on the accessibility of the fitness centres. Considering that these types of centres use customer management software in addition to customer relationship management (CRM) systems, a data collection procedure was chosen through online surveys, with the fitness centres themselves responsible for mass sending to their databases, ensuring users' confidentiality of information as well as voluntary participation, asking for maximum sincerity and honesty as there were no correct or incorrect answers. The time taken to complete all items of the questionnaire ranged from 7 to 8 minutes.
Data analysis involved a descriptive approach, using absolute frequency distributions and percentages for sociodemographic variables. This analysis was segmented by the following recorded variables: gender (female and male), age range in years (under 20, 21-30, 31-40, 41-50, 51-60, and over 61), previous experience (whether they had been previously registered at a fitness centre or not), length of membership at the fitness centre in months (up to 3, 4-6, 7-12, 13-24, and more than 25), and weekly attendance frequency in days (1, 2, 3, 4, and 5 or more). The Sex and Gender Equity in Research (SAGER) Guidelines were followed by the authors.
4. RESULTS
The data analyses conducted showed how participation has remained very stable by gender, with women accounting for over 50%, and the average percentage for women (53.6%) being higher than that of men (43.4%). In terms of age, while users aged between 21 and 30 represent the group with the highest percentage of participation (31.3%), it is noteworthy that their presence has decreased by 14.3% during the observed period, presenting in 2018 a similar percentage (26.8%) to users aged between 41 and 50 years (26.5%) and slightly below the age range of 31 to 40 years (28.6%). On the other hand, there was an increase since 2014 in the percentage of users aged between 31 and 40 years (+2.9%), between 41 and 50 (+8.8%), and between 51 and 60 years (+4.1%). This change coincides with the trends reported in official statistics and studies on the increase in sports practice among adults over 40 years of age [10, 11]. Most users reported having previously attended another sports centre (n = 33,154; 77.3%), while 22.7% (n = 9,713) were first-time users of such services, without significant variation in the evolution of the percentages obtained during the observed period (Table 1).
The data in Table 2 reveal a clear shift in user retention patterns from 2014 to 2018. In the earlier years, shorter-term stays, particularly those lasting up to 6 months, were more common. However, over time, a noticeable transition toward longer durations has occurred. The category of 13 to 24 months consistently represented the largest group overall (25.5%), demonstrating steady growth. Particularly notable is the significant increase in users staying more than 24 months, which rose from 5.8% in 2014 to 28.1% in 2018. These trends indicate a marked improvement in user retention and long-term engagement [14].
| Variables |
2014 (n=1,314) |
2015 (n=8,462) |
2016 (n=15,820) |
2017 (n=6,903) |
2018 (n=10,368) |
Total (42,867) |
|---|---|---|---|---|---|---|
| - | n (%) | n (%) | n (%) | n (%) | n (%) | n (%) |
| Gender | - | - | - | - | - | |
| Woman | 713 (54.3) |
4,303 (50.9) |
8,462 (53.5) |
3,643 (52.8) |
5,864 (56.6) |
22,985 (53.6) |
| Man | 60 (45.7) |
4,159 (49.1) |
7,358(46.5) | 3,260 (47.2) |
4,504 (43.4) |
19,882 (46.4) |
| Age | - | - | - | - | - | - |
| < 20 | 85 (6.5) |
518 (6.1) |
908 (5.7) |
219 (3.2) |
388 (3.8) |
2,118 (4.9) |
| 21-30 | 540 (41.1) |
3,068 (36.3) |
5,313 (33.6) |
1,726 (25.0) |
2,781 (26.8) |
13,428 (31.3) |
| 31-40 | 338 (25.7) |
2,516 (29.7) |
4,698 (29.7) |
2,124 (30.8) |
2,970 (28.6) |
12,646 (29.5) |
| 41-50 | 233 (17.7) |
1,585 (18.7) |
3,316 (21.0) |
1,821 (26.4) |
2,750 (26.5) |
9,705 (22.6) |
| 51-60 | 94 (7.2) |
601 (7.1) |
1,275 (8.1) |
804 (11.6) |
1,168 (11.3) |
3,942 (9.3) |
| > 60 | 24 (1.8) |
174 (2.1) |
310 (2.0) |
209 (3.0) |
311 (3.0) |
1,028 (2.4) |
| Previous experience | - | - | - | - | ||
| Yes | 1,048 (79.8) |
6,760 (79.9) |
12,118 (76.6) |
5,317 (77.0) |
7,911 (76.3) |
33,154 (77.3) |
| No | 266 (20.2) |
1,702 (20.1) |
3,702 (23.4) |
1,586 (23.0) |
2,457 (23.7) |
9,713 (22.7) |
| - | 2014 | 2015 | 2016 | 2017 | 2018 | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | n | % | n | % | |
| LM | - | - | - | - | - | - | - | - | - | - | ||
| 0-3 | 239 | 18.2 | 2,033 | 24.0 | 3,466 | 21.9 | 864 | 12.5 | 1,469 | 14.2 | 8,071 | 18.8 |
| 4-6 | 331 | 25.2 | 2,228 | 26.4 | 2,308 | 14.6 | 1,302 | 18.9 | 1,810 | 17.4 | 7,979 | 18.6 |
| 7-12 | 376 | 28.6 | 1,453 | 17.2 | 3,040 | 19.2 | 858 | 12.4 | 1,510 | 14.6 | 7,237 | 16.9 |
| 13-24 | 292 | 22.2 | 2,102 | 24.8 | 4,111 | 26.0 | 1,773 | 25.7 | 2,668 | 25.7 | 10,946 | 25.5 |
| >24 | 76 | 5.8 | 646 | 7.6 | 2,895 | 18.3 | 2,106 | 30.5 | 2,911 | 28.1 | 8,634 | 20.1 |
| Total | 1,314 | 100 | 8,462 | 100 | 15,820 | 100 | 6,903 | 100 | 10,368 | 100 | 42,867 | 100 |
| WA | - | - | - | - | - | - | - | - | - | - | - | |
| 2 or fewer | 220 | 16.8 | 1,854 | 21.9 | 3,408 | 21.5 | 1,549 | 22.4 | 2,649 | 25.5 | 9,680 | 22.6 |
| 3 | 418 | 31.8 | 3,003 | 35.5 | 5,310 | 33.6 | 2,289 | 33.2 | 4,236 | 40.9 | 15,256 | 35.5 |
| 4 | 676 | 51.4 | 3,605 | 42.6 | 7,102 | 44.9 | 3,065 | 44.4 | 3,483 | 33.6 | 17,931 | 41.9 |
| Total | 1314 | 100 | 8,462 | 100 | 15,820 | 100 | 6,093 | 100 | 10,368 | 100 | 42,867 | 100 |
| NPS | - | - | - | - | - | - | - | - | - | - | - | |
| D | 181 | 13.8 | 2,920 | 34.5 | 7,349 | 46.5 | 1,750 | 25.4 | 2,586 | 24.9 | 14,786 | 34.5 |
| N | 568 | 43.2 | 2,898 | 34.2 | 4,823 | 30.5 | 2,873 | 41.6 | 4,206 | 40.6 | 15,368 | 35.9 |
| P | 565 | 43.0 | 2,644 | 31.2 | 3,648 | 23.1 | 2,280 | 33.0 | 3,576 | 34.5 | 12,713 | 29.7 |
| NPSI | - | 29.2 | - | -3.3 | - | -23.4 | - | 7.6 | - | 9.6 | - | -4.8 |
| Total | 1,314 | 100 | 8,462 | 100 | 15,820 | 100 | 6,903 | 100 | 10,368 | 100 | 42,867 | 100 |
Weekly attendance patterns show a high level of user engagement. The most frequent pattern observed over the years was four times per week, accounting for 41.9% of the total. This was followed by users attending three times per week (35.5%). Those attending two times or fewer per week constituted the smallest proportion (22.6%). This distribution suggests that most users maintain a consistent and frequent routine, likely reflecting strong commitment and a desire to achieve measurable results [16, 20].
NPS trends exhibit an inconsistent pattern over the five years. While the score was positive in 2014 (29.2b), a sharp decline occurred in 2015 and especially in 2016, reaching a negative peak of 23.4. This drop can be attributed to a surge in detractors, who comprised 46.5% of respondents in 2016, coupled with a significant decrease in promoters (down to 23.1%). A partial recovery began in 2017, with the NPS improving to 7.6 and then to 9.6 in 2018, as the share of detractors gradually declined. However, the score has not yet returned to the levels observed in 2014, suggesting that although improvements have been made, there are still relevant areas for enhancing the user experience. These results may reflect a deterioration in the perceived quality of the service, a key aspect for satisfaction and recommendation, according to several studies [23].
5. DISCUSSION
This discussion focuses on the key findings derived from the longitudinal analysis of consumer profile evolution in low-cost fitness centres over the past five years (2014-2018), contrasting them with existing literature. We have structured this section to address the core results related to consumer profile and consumer behaviour, aligning with the study's objectives.
Our study reveals a significant shift in the demographic profile of users in low-cost fitness centres. A central finding is the increase in the number of users aged between 41 and 60. This observation is crucial, and while a five-year study period might not be sufficient to establish a definitive generational migration, it does suggest an emerging trend that warrants further investigation. This could be interpreted as a combination of factors: on one hand, a possible maturation of the younger user base who have remained within the low-cost model, and on the other, a growing interest among the adult population in physical activity and health, driven by increased social awareness and the availability of accessible facilities. This trend aligns with general reports and surveys confirming an increase in the practice of healthy habits and physical activity among adults and older individuals, directly impacting the demographic composition of low-cost gyms.
This change in consumer profile reinforces the need for fitness centre operators to adjust their offerings. While studies like those by Valgo [55-58] provide valuable reports on user profiles in Spain, our findings suggest that a deeper understanding is required not only of demographic profiles but also of the specific motivations and needs of these age segments. This is fundamental for proper segmentation and for adapting value propositions, as highlighted by Funk et al. [59] regarding the importance of improving quality and user satisfaction by more effectively meeting their needs.
Regarding consumer behaviour, the study shows greater exercise adherence among users of low-cost fitness centres, evidenced by an increase in weekly usage frequency and longer monthly retention. Specifically, we observe an upward trend in the percentage of users visiting centres two or three times a week, which promotes adherence and thus solidifies healthy habits. The average user lifespan in these types of fitness centres has also increased, ranging from 13 to 24 months, with a notable increase for those with retention periods exceeding 24 months. This data could be a consolidation of the low-cost model and its ability to foster continuity in sports practice.
However, a significant finding that requires deeper discussion is the negative trend in the NPS, with an increase in detractors and neutral users and a decrease in promoters. A possible explanation for this decline in net user satisfaction, despite greater adherence and retention, could lie precisely in accumulated experience. As users spend more time in these centres and become more established in their practice, they develop a greater familiarity with the service and, consequently, higher expectations regarding personalisation and adaptation to their needs. The initial value proposition of low-cost, focused on accessibility and basic equipment, might not be enough to satisfy these more sophisticated demands from long-term users. This phenomenon suggests that perceived quality and value evolve over time, and low-cost centres must consider how to meet these growing needs to maintain loyalty and convert users into promoters.
This study's findings underscore the dynamic evolution of consumers in the low-cost fitness sector. While greater adherence and retention are observed, the shift in demographic profile towards older age segments and the decline in NPS highlight the need for operators to re-evaluate and adjust their strategies to meet the changing expectations of their users.
In terms of management implications, this work addresses the evolution of the user profile in low-cost fitness centres, as well as the behaviour regarding physical activity practice in these types of centres. Currently, there are no studies in academic literature that have analysed the profile of consumers in low-cost fitness centres through sociodemographic variables, so the results obtained meet a market need and are especially valuable for the management teams of these centres. Therefore, the data obtained can be used to improve the service offerings as well as to adapt them according to the user types and consumption behaviour, which adds even more value considering that this is a business model with significant resource limitations for its management.
CONCLUSION
The evolution of consumers in low-cost fitness centres reflects a constantly changing sector driven by economic and social factors. The 2007 crisis and the VAT increase in 2012 facilitated the expansion of this model, attracting more users, especially adults aged 41 to 60. The increase in usage frequency and retention would indicate greater exercise adherence, though accumulated experience would lead to higher demands for personalisation and service quality. To remain competitive, fitness centres must adjust their offerings and improve segmentation. The growing interest in health and wellness will continue to strengthen this model, creating opportunities for service innovation and customer retention.
LIMITATIONS AND FUTURE RESEARCH
Finally, among this study's limitations, while variables capable of predicting consumer evolution in low-cost fitness centres were identified, their quantity is limited. Moreover, the non-probabilistic sampling limits the generalizability of the results to the broader population of users within the low-cost model. Therefore, future research should focus on analysing variables, services, or needs most demanded by users of low-cost fitness centres to increase their ratings and recommendation indices. This also suggests a potential area for future studies: analysing the evolution and statistics of user numbers in sports facilities based on age, particularly focusing on the adult or older population. Such research should explore their reasons and satisfaction indices to adapt activity offerings and equipment within these facilities. This would aim to increase loyalty rates since, despite it being a model that offers very low prices for customers, customer loyalty remains difficult to achieve [60].
AUTHORS’ CONTRIBUTIONS
The authors confirm their contribution to the paper as follows: G.R.P.: Conceptualization G.F.J.: Investigation A.S.: Analysis and interpretation of results: AS G.P.M., B.G.A.: Draft manuscript. All authors reviewed the results and approved the final version of the manuscript.
LIST OF ABREVIATIONS
| VAT | = Value added tax. |
| NPS | = Net Promoter Score. |
| CRM | = Customer Relationship Management. |
ETHICS APPROVAL AND CONSENT TO PARTICIPATE
As this study was based on anonymised secondary data collected through client management systems and self-administered surveys voluntarily distributed by the fitness centres to their registered users, the researchers did not access any personally identifiable information. Therefore, ethical approval was not applicable, in accordance with national and institutional guidelines for observational research using anonymised datasets.
CONSENT FOR PUBLICATION
As this study was based on anonymised secondary data collected through client management systems and self-administered surveys voluntarily distributed by the fitness centres to their registered users, the researchers did not access any personally identifiable information. Therefore, informed consent was not applicable, in accordance with national and institutional guidelines for observational research using anonymised datasets.
AVAILABILITY OF DATA AND MATERIALS
All data generated or analyzed during this study are included in this published article.
FUNDING
The publication is part of grant JDC2022-048886-I, funded by MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR.
CONFLICT OF INTEREST
The author Dr. Jerónimo García-Fernández is the Associate Editorial Board Member of TOSSJ.
ACKNOWLEDGEMENTS
Declared none.
APPENDIX 1
Questions collected in the questionnaire:
• Gender:
o Woman
o Man
• Age:
o Under 20 years
o 21-30 years
o 31-40 years
o 41-50 years
o 51-60 years
o Over 60 years
• Do you have previous experience as a client of gyms or fitness centers?"
o Yes
o No
• How long have you been a member of this fitness center?
o 0-3 months
o 4-6 months
o 7-12 months
o 13-24 months
o More than 24 months
• In a typical week, how often do you visit this fitness center?
o 2 or fewer times/week
o 3 times/week
o 4 times/week
• On a scale of 0 to 10, how likely are you to recommend this fitness center to a friend or colleague?
