The construct of attachment was originally used to characterize the close emotional bond between a child and his or her caregiver (e.g., usually the parents). John Bowlby (1977) defined attachment as “the propensity of human beings to make strong affectional bonds to particular others” (p. 201). Mary Ainsworth et al. (1978) employed the “Strange Situation” procedure to investigate individual differences in infant attachment to primary caregivers. This research led to the identification of distinct attachment styles.

Ainsworth et al. (1978) established a link between consistent, attentive, responsive, and supportive caregiving and the development of secure attachment in infants. Conversely, consistently unresponsive, distant, and aloof caregiving was associated with the development of an insecure-avoidant attachment style (Ainsworth et al., 1978). Furthermore, unpredictable and inconsistent caregiving behaviors were found to promote an insecure-anxious attachment style (Ainsworth et al., 1978).

The attachment system, initially conceptualized by Bowlby (1977) and Ainsworth et al. (1978), has been subsequently broadened to encompass relationships beyond infancy, extending into adolescence and adulthood (Fraley et al., 2005). This perspective has spurred substantial research over the past two decades (see Mikulincer & Shaver, 2013, for a review). More recently, numerous self-report measures have been developed to assess attachment styles across various relational contexts (see Justo-Núñez et al., 2022, for a review), including romantic relationships (e.g., Experiences in Close Relationships Scale, Brennan et al., 1998) and adolescent friendships (e.g., Adolescent Friendship Attachment Scale, Wilkinson, 2008).

Within organized sport, it has been suggested that athletes’ relationships with their coaches may become an important aspect of development and growth (Jowett & Cockerill, 2003), and that attachment theory can supply a sound theoretical framework for studying individual differences within the interpersonal relational context formulated by the coach and the athlete (Davis & Jowett, 2010).

To expedite research on coach-athlete attachment, and to address limitations of existing instruments designed for different contexts (e.g., adolescence) and attachment figures (e.g., romantic partners), Louise Davis and Sophia Jowett (2013) developed the Coach-Athlete Attachment Scale (CAAS). This instrument measures athletes’ attachment to their coaches across the three mentioned primary attachment styles.

The CAAS (19 items) was designed to measure athletes’ secure (5 items, e.g., “I know I can rely on my coach”), anxious (7 items, e.g., “I worry that I won’t fulfill my coaches’ expectations”), and avoidant (7 items, e.g., “I do not turn to my coach for reassurance”) attachment styles. Although the original study focused on measuring the three attachment styles (secure, anxious, and avoidant), Davis and Jowett (2013) also derived a measure of attachment security based on athletes reporting low levels of both attachment avoidance and anxiety. This approach to inferring security from low avoidance and anxiety has precedent in adult attachment measures (e.g., the Experiences in Close Relationships Scale; Brennan et al., 1998).

As noted by Davis and Jowett (2013), the development of the Coach-Athlete Attachment Scale (CAAS) as a new instrument for measuring attachment within the sport context was carried out in three phases. In the first phase, items were generated based on pre-existing self-report attachment instruments, adapted specifically for the sporting context to reflect the attachment styles of both coaches and athletes. In the second phase, a panel of experts evaluated the content validity of the items, which allowed for the construction of a final version of the scale.

Finally, in the third phase, the CAAS was administered to a sample of 703 participants (405 coaches and 298 athletes), and a confirmatory factor analysis (CFA) was conducted to determine the final structure of the scale.

The bifactorial structure comprising 14 items, assessing insecure-anxious and avoidant attachment in both athletes and coaches, showed satisfactory goodness-of-fit indices (athletes; SRMR = 0.06, RMSEA = 0.05, RCFI = 0.96, RNNFI = 0.95), (coaches; SRMR = 0.06, RMSEA = 0.06, RCFI = 0.94, RNNFI = 0.89), as did the three-factor model of 19 items assessing secure, anxious, and avoidant attachment in athletes (SRMR = 0.06; RMSEA = 0.04; RCFI = 0.97; RNNFI = 0.97), and in coaches (SRMR = 0.06; RMSEA = 0.06; RCFI = 0.90; RNNFI = 0.89).

Subsequently, the CAAS has been adapted to other languages and cultures and has been validated in Chinese (Peng et al., 2020), Swedish (Davis et al., 2022), and Turkish (Bastık & Gümüşdağ, 2022). The Chinese version (Peng et al., 2020) consisted of only two subscales (anxiety and avoidance), and its reduced version exhibited good psychometric properties, including reliability and validity. The Swedish (Davis et al., 2022) and Turkish (Bastık & Gümüşdağ, 2022) versions of the CAAS kept all three subscales (with 19 items), and their analysis further confirmed the reliability and validity of the questionnaire. However, to date and to our knowledge, there has been no research that has attempted to validate a Spanish version of the CAAS.

In relation to the structure of the CAAS, the literature has proposed two models of measurement. On the one hand, the bifactorial model, composed of anxious and avoidant attachment, allows security to be inferred from low scores in both dimensions, in line with adult attachment measures such as the ECR (Brennan et al., 1998). On the other hand, the trifactorial model directly evaluates the three attachment styles (secure, anxious, and avoidant), consistent with Ainsworth et al. (1978) classification and with Davis and Jowett (2013) initial validation of the CAAS. Both structures have shown acceptable psychometric properties in international adaptations (Peng et al., 2020; Davis et al., 2022; Bastık & Gümüşdağ, 2022). Therefore, it is relevant to contrast both models in the Spanish adaptation, to determine which provides a more robust measurement in this context.

In addition, a recent systematic review compiling 16 international studies has highlighted that the CAAS is the most widely used instrument for assessing attachment in the sporting context, showing how secure attachment in athletes directly impacts their subjective psychological well-being through variables such as vitality, performance, and self-esteem. It also reports higher satisfaction rates with the athlete-coach relationship and has a positive impact on physical and psychological health, preventing burnout, recovery from injuries, or eating disorders in athletes, while insecure-anxious and avoidant styles represent a challenge in the sports context due to their excessive emotional dependence on the coach or, conversely, their distancing and marked autonomy from the coach and technical staff (See more in Valls-Barberá & Magallares, 2025).

Likewise, the same review shows how language represents a barrier to the assessment of attachment style in athletes. For example, in the study by Nayara Caruzzo et al. (2021), it is indicated that some of the participants in the beach volleyball world championship were unable to participate in the study because they did not understand English, which reinforces the need to validate the CAAS in as many languages as possible so that all athletes can participate in the measurements. Therefore, considering the usefulness of a self-report instrument specifically designed to assess athletes’ attachment styles, the objective of this research was to adapt the CAAS to Spanish (Sp-CAAS) in a sample of soccer players.

In this sense, validating the CAAS in Spanish not only addresses a linguistic gap but also allows researchers to advance the study of how attachment shapes the coach–athlete relationship, a central relational context in sport. Moreover, by incorporating longitudinal measurement invariance and test–retest reliability analyses—approaches that have not been applied to the CAAS so far—this study provides a novel methodological contribution that strengthens the evidence for the instrument’s psychometric properties.

Considering the utility of a self-report instrument designed to assess athletes’ attachment styles, the aim of this research was to adapt the CAAS to Spanish (Sp-CAAS) in a sample of football players. Given the global prevalence of Spanish, with approximately 600 million speakers worldwide (Eberhard et al., 2022), and the significant number of football players in Spanish-speaking countries, such as Spain’s 1,248,511 federated players (Ministry of Education, 2024), we believe that measures developed specifically for Spanish-speaking populations, for athletes and, in the context of this study, for soccer players, are very valuable. Therefore, the main objective of this research was to adapt the CAAS into Spanish to develop a Spanish version while maintaining the same factor structure and number of items as the original scale, resulting in the Sp-CAAS using the translation/back-translation methodology and following the guidelines for cross-cultural adaptations (Hernández et al., 2020).

In addition, taking into account the variability in the factor structure of the scale, we set out to evaluate the two original factor structures of the scale proposed by Davis and Jowett (2013), the two-factor scale of insecure attachment (anxious and avoidant) and the three-factor scale (secure, anxious, and avoidant).

As a novelty, and to advance our understanding of the psychometric properties of the CAAS, we conducted a test-retest reliability analysis. Moreover, to assess the temporal stability of the CAAS, we employed Longitudinal Measurement Invariance (LMI). This innovative approach, previously unexplored with the CAAS, allowed us to examine the extent to which the attachment construct measured by the CAAS remained invariant over time (Millsap & Cham, 2012).

Finally, to study the convergent and discriminant validity of the CAAS, the Basic Needs Satisfaction in Sport Scale (Jowett & Ntoumanis, 2004) and the Coach-Athlete Relationship Questionnaire (Ng et al., 2011) were measured, as previous research has found that the CAAS was positively related to athletes’ basic psychological needs satisfaction (Davis et al., 2021) and to athletes’ meta-perceptions of the quality of the coach-athlete relationship (Davis et al., 2022).

The aim of this study was to investigate the psychometric properties of the CAAS with a sample of Spanish athletes for its adaptation into Spanish, allowing Spanish-speaking athletes to participate in the measurement of attachment styles, thus overcoming the language barrier that has conditioned studies with international athletes such as that of Caruzzo et al. (2021). In addition to contributing its Spanish version, the availability of the Sp-CAAS in Spain provides literature and support to Spanish-speaking countries, being at the forefront with the results obtained in the systematic review by María Valls-Barberá and Alejandro Magallares (2025), which showed that this instrument is the most widely used internationally for the assessment of attachment styles as a relational personality variable, joining the English, Chinese, Swedish, and Turkish versions.

Likewise, in fulfilling our objective of adapting the coach-athlete attachment scale, this study contributes to current and future lines of research aimed at promoting the use of specific attachment measurement instruments in the field of sports (Davis & Carr, 2024).

Based on the theoretical evidence related to Bowlby’s attachment theory (1977) and Ainsworth et al.’s (1978) classification of attachment into two broad clusters, which include two styles of insecure attachment (anxious and avoidant) and secure attachment, two measurement models were tested to assess the three styles. First, the findings from the CFA of the two-factor model, which includes the dimensions of anxiety and avoidance, showed an acceptable fit, meeting the criteria of several goodness of fit indexes and aligning with measures that assess adult attachment in close and romantic/marital relationship contexts such as the Experiences in Close Relationships Scale (Brennan et al., 1998). Specifically, the two-dimensional Sp-CAAS focuses on directly assessing insecure attachment styles (avoidant and anxious), whilst the secure attachment style is inferred by athletes rating low scores on both the anxious and avoidant attachment dimensions.

Furthermore, the CFA from the three-factor model, which includes the dimensions of avoidance, anxiety, and security, also revealed an acceptable fit to the data. Although the two-factor model allows for inferring attachment security, the three-dimensional measure (avoidant, anxious, and secure styles) allows for the direct measurement of all three attachment styles that underline individual differences in terms of relating, communicating, and interacting within the dyadic coach-athlete context. This follows the work of Ainsworth and colleagues (1978), and Davis and Jowett’s (2013) initial validation of the CAAS. Together, both the two-factor and three-factor models illustrate an acceptable means of tapping into the three dimensions of attachment.

However, considering that the three-factor model allows for the direct assessment of secure attachment, rather than inferring it from low anxiety and avoidance, it may provide a more comprehensive measurement of athletes’ attachment styles. Therefore, although both models are supported, the trifactorial structure appears to be the most suitable option for the Spanish adaptation of the CAAS.

In line with the model respecification reported in the results section, the correlated residuals between items 1 and 2 within the avoidant attachment factor likely reflect their conceptual overlap rather than a misunderstanding of item meaning. During the pilot testing, none of the football players reported any difficulty distinguishing between the two statements, supporting this interpretation. Nevertheless, because this adjustment was specific to the Spanish sample, future studies should examine whether it replicates across other Spanish-speaking populations to further support the cross-cultural validity of the Sp-CAAS.

As a novel contribution to the literature, we conducted the first-ever assessment of both the test-retest reliability and the longitudinal factorial stability of the CAAS using CFA. Unlike previous studies, neither the original (Davis & Jowett, 2013) nor adapted versions of the CAAS (Bastık & Gümüşdağ, 2022; Davis et al., 2022; Peng et al., 2020) have incorporated such rigorous longitudinal analyses. We believe that our findings demonstrate the instrument’s excellent temporal stability. We contend that LMI offers a robust and reliable foundation for longitudinal comparisons, as outlined by Roger Millsap and Heining Cham (2012).

The reliability of the three subscales (avoidant, anxious, and secure) was found to be high, consistent with the original English version (Davis & Jowett, 2013) and subsequent adaptations in Swedish (Davis et al., 2022) and Turkish (Bastık & Gümüşdağ, 2022). Specifically, the Chinese version of the CAAS-14 (excluding secure attachment items) also demonstrated comparable Cronbach’s alpha values (Peng et al., 2020). While the Cronbach’s alpha values for our adaptation ranged from .78 to .88, the Swedish CAAS (Davis et al., 2022) reported values between .88 and .89, the Turkish version (Bastık & Gümüşdağ, 2022) yielded values between .70 and .75, and the reduced Chinese CAAS-14 (Peng et al., 2020) exhibited satisfactory reliability with values ranging from .72 to .81. Lastly, it is important to highlight that as a novelty in this research, in addition to calculating Cronbach’s alpha, omega coefficients were also estimated to measure the reliability of the Sp-CAAS.

Finally, evidence of convergent and discriminant validity was established. The three dimensions of the Sp-CAAS were significantly correlated with athletes’ satisfaction of basic psychological needs (Davis et al., 2021) and their meta-perceptions of coach-athlete relationship quality (Davis et al., 2022), aligning with existing literature. These findings suggest that athletes’ secure attachment orientations towards their coaches play a crucial role in fostering feelings of autonomy, competence, and relatedness (measured by the BNSS; Davis et al., 2021), as well as closeness, commitment, and complementarity (assessed by the CART-Q; Davis et al., 2022).

Based on these results, the Sp-CAAS appears to be a useful tool for measuring athletes’ attachment styles. According to the results obtained in our study, the Sp-CAAS can be considered a valid and reliable tool that can be used successfully in Spain to assess athletes’ relational personality and thus provide sufficient information to enable coaching staff, sports psychologists, and other sports professionals involved to create an optimal sporting environment where athletes are treated with the caution required by anxious styles in terms of excessive emotional dependence and constant demand for attention, with the flexibility to provide the autonomy required by avoidant styles, as well as working with insecure styles to improve their overall well-being and create an environment of trust where the coach can become a secure base for the athlete and thus reduce their relational limitations. At the same time, it enhances the competence, relationship, autonomy, closeness, complementarity, and commitment of secure styles (Valls-Barberá & Magallares, 2025).

Despite the strengths of this study, several limitations should be acknowledged. First, there was a gender imbalance in the sample, with 78% of participants being male. However, although more girls are now participating in football, a significant gender gap remains (Martínez-Andrés et al., 2017).

Second, self-report measures may limit the accuracy of assessing attachment styles, although they do not require a full understanding of relational dynamics to be valid (Brennan et al., 1998).

Third, the study focused exclusively on athletes, and therefore psychometric properties of the coach version of the CAAS were not examined. Given the bidirectional nature of the coach–athlete relationship (Davis & Carr, 2024), future research should validate the coach version of the instrument.

In addition, the post hoc correlation between items 1 and 2 of the avoidant factor, although theoretically justified and improving model fit, requires replication in new samples as it was based on the same dataset. Finally, although the longitudinal CFA supported the stability of the instrument over time, replication with larger samples would strengthen the generalizability of the findings.

This research provides evidence that the Sp-CAAS is an appropriate tool for measuring the athletes’ attachment styles with Spanish speakers. The present study highlights only marginal differences between the English and the Spanish versions of the CAAS, suggesting that this scale can capture athletes’ attachment styles across diverse cultural contexts. Nevertheless, further studies are recommended to confirm its content validity and to test its psychometric performance across other Spanish-speaking populations to ensure its cross-cultural robustness.

This study was conducted in accordance with the Declaration of Helsinki and the Ethical Standards in Sport and Exercise Science Research.