Doping has marked the world of competitive sport in the last years, with the Puerto case in 2006 or the Lance Armstrong case in 2012 being evident examples. The World Anti-Doping Agency (WADA) issued and periodically updates the Anti-Doping Code with the aims of protecting the athlete's fundamental right to participate in dopingfree sport and thus promotes health, fairness and equality for athletes worldwide, warranting harmonized, coordinated and effective anti-doping programmes at the international and national level relating to the detection, deterrence and prevention of doping (David, 2013).
Doping in sport has been studied by medical, physiological and social science researchers for many years with the purpose of developing a better understanding and prevention (Backhouse et al., 2007; Morente-Sanchez and Zabala, 2013). According to the Theory of Planned Behaviour (Ajzen, 1991) behaviour depends on people's plans of actions towards that behaviour (intentions), which are regulated by people's perceived behavioural control, their subjective norms, and attitudes. Lucidi et al. (2008) defined "attitudes" as "positive or negative evaluative appraisals of the behaviour" and, showed that attitudes towards doping are known to influence doping use and to play an important role as predictor of intention to use banned substances (doping behaviour). In a recent study (Barkoukis et al., 2013), it was stated that distal influences (self-determination, sportpersonship orientations and achievement goals) have an indirect effect on proximal influences such as situational temptation and perceived behavioural control, descriptive and subjective norms, and attitudes, and in turn these have a direct influence on doping intentions. Thus research aiming to investigate doping attitude can generate useful information to inform the fight against doping. Through the high profile doping cases, it has become evident that controlling doping only by tests is not sufficient. A profound change in the attitudes is needed, which should be continuously monitored (Alaranta et al., 2006).
In relation to the type of measurement tools used in the scientific literature to assess attitudes towards doping, just a few studies used validated tools while the majority of researchers used ad hoc bespoke measurements without psychometric testing, and thus potentially jeopardised the validity and reliability of the obtained data (Morente-Sanchez and Zabala, 2013). Furthermore, such bespoke measurements make direct comparisons and metaanalyses of independent studies impossible. In order to address this gap, Petroczi and Aidman (2009) proposed using the Performance Enhancement Attitude Scale (PEAS), originally developed by Petroczi (2002), as a standard general doping attitude measure in doping behaviour studies.
However, the applicability of this kind of measurement should be tested in different cultural contexts and languages than the ones in the original version, in which the scale showed good psychometric properties in both English and Hungarian speaking participants (Petroczi and Aidman, 2009). Therefore, the adaptation and psychometric validation of this scale to other widely spoken languages is an important issue to facilitate cross-cultural comparisons.
According to Lewis (2009), Spanish, also called-Castilian, is the second most spoken language worldwide, with 406 million of first-language speakers in 31 countries. In addition, regarding sport, Spanish is considered as an important and common language due to the fact that Spain is one the most main references in the sporting world in recent years, along with other Spanish speaking countries (e.g. in South-America). From this point of view, the cross-cultural adaptation of the PEAS for Spanish is an essential step in doping behaviour research, antidoping prevention and intervention and related decisionmaking. Although the PEAS has been already used in studies with samples comprised of Spanish participants (Morente-Sanchez et al., 2013), psychometric validation and cross-cultural adaptation of its Spanish version is not yet available in the scientific literature. Therefore, taking everything into account and considering the international view about the phenomenon of doping in Spanish sport, the aim of this study was to cross-culturally adapt and validate the Spanish version of the original Performance Enhancement Attitude Scale (Petroczi, 2002).
The sequential methodological approach proposed by Guillemin et al., (1993) and Beaton et al., (2000) was used for guiding the cross-cultural adaptation process of the PEAS. First, the 17 items were translated into Spanish by two independent native Spanish translators. A synthesis of the two was performed by an expert committee composed of a panel of experts (including the authors of this work). Then the resulting Spanish questionnaire was back-translated into English by two independent English-native translators and the two questionnaires obtained were reviewed by the expert committee. Finally, the Spanish-translated questionnaire (Table 1) was tested with 30 participants (pilot study) to ensure that the questionnaire was perfectly clear and understandable like they confirmed immediately after by means of an interview one by one.
This paper summarizes a series of studies that used the PEAS as a measure of doping attitudes. Eighteen independent datasets collected from different sporting contexts, mainly cycling and football, were considered for this study. Specifically, six samples from individual sports such as cycling and triathlon were assessed: high level cycling team managers, elite female cyclists and triathletes, elite male cyclists from Spanish national team, amateur cyclists or ciclotourists who participated in a long-distance (205 km) Spanish road cyclist event called "Quebrantahuesos" (2011 and 2012 editions). Similarly, seven samples related to a team sport such as football were evaluated: male players (under16, amateur, professionals and elite), female players (elite), coaches from different categories and a sample comprised of the so-called environment of footballers (doctor, physiotherapist, etc.). In addition, five sets of student samples were composed of undergraduates from different years of the Faculty of Sport Sciences of Granada (Spain). Details on different samples such as sample sizes, age (mean--standard deviation), gender distribution (expressed as ratio) and data collection, are given in Table 2.
In order to establish evidence for convergent validity, the questionnaire for amateur cyclists samples (2011 and 2012 editions) also included measures of variables expected to be related to doping attitudes (measured by PEAS) such as self-esteem, self-efficacy and projected use.
Self-esteem was assessed by the Rosenberg Self-Esteem Scale (RSES), which is made up of 10 items that refer to self-respect and self-acceptance rated on a 4-point Likert-type scale, ranging from 1 (totally disagree) to 4 (totally agree) (Rosenberg, 1965). Martm-Albo et al., (2007) cross-culturally adapted and validated the Spanish version of this scale (Cronbach a = 0.8-0.85) was used.
Following Bandura's guide for constructing self-efficacy scales (Bandura, 2006), self-efficacy beliefs were also measured with three statements rated on a 10-point scale ranging from "not certain at all" to "totally certain". The items were: a) You can achieve your best results without doping; b) You do not need doping to be a good cyclist, and c) You can succeed (win, beat records) without doping.
Descriptive norms were measured by asking participants to give a projected percentage of those using of doping is their respective sports.
Of the 18 datasets in total, 14 used paper-and-pencil instruments, whereas in 4 samples, an electronic version of PEAS...