Individual Factors and the Context of Physical Activity in Exercise ...

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physical activity could be applied to exercise dependence, and that exercise ... Physical activity (i.e., exercise) can be defined as a health-related behaviour ...
Int J Ment Health Addiction (2007) 5:233–243 DOI 10.1007/s11469-007-9081-9

Individual Factors and the Context of Physical Activity in Exercise Dependence: A Prospective Study of ‘Ultra-Marathoners’ Benjamin Allegre & Pierre Therme & Mark Griffiths

Received: 6 September 2006 / Accepted: 12 April 2007 / Published online: 1 May 2007 # Springer Science + Business Media, LLC 2007

Abstract Although there is a growing body of literature examining determinants and correlates of exercise dependence, there has been a lack systematic measures of individual factors combined with the context of physical activity characteristics. The aim of this prospective study was therefore to examine the relative influence of individual factors and environmental context of physical activity on exercise dependence. This study examined a group of 95 ‘ultra-marathoners’ of a 100 km race. Each participant completed a questionnaire that assessed individual factors (e.g., sex, age, BMI, marital status, etc.), context of the physical activity (e.g., environmental and social context of practice), and the effect on the body as a result of physical activity (e.g., body control and modification). For participants in this study, the strongest predictors of exercise dependence were individual factors (age and BMI), and exercising in the city in an unstructured space. It is concluded that an ecological model of physical activity could be applied to exercise dependence, and that exercise dependence could provide interesting insights into the promotion of physical activity as a health-related behaviour. Keywords Exercise dependence . Exercise addiction . Physical activity . Social and environmental context

Introduction Physical activity (i.e., exercise) can be defined as a health-related behaviour (Biddle and Fox 1989) because of its capacity to yield both physiological and psychological benefits (US Department of Health and Human Services 1996). For example, research has shown that physical activity is inversely related to the incidence of cardiovascular diseases, B. Allegre (*) : P. Therme UPRES EA 32 94, Faculté des Sciences du Sport, 163 Avenue de Luminy-CP 910F, Marseille 13288, France e-mail: [email protected] M. Griffiths Division of Psychology, Nottingham Trent University, Burton Street, Nottingham, NG1 4BU, UK

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osteoporosis and diabetes (Vuori 1998), and the decrease of depression or anxiety (Salmon 2001). Despite beneficial health effects, research has indicated that exercise can become an unhealthy activity in some individuals, and may produce several negative outcomes (Biddle 1995). For example, research studies have shown that exercise can interfere with family work or social responsibilities (Bamber et al. 2003; Terry et al. 2004; Veale 1995), and produce withdrawal symptoms in some individuals when they cannot exercise (Griffiths 1997; Szabo 1995, 1998). Furthermore, some individuals will continue to exercise despite a persistent and/or recurrent physical and/or psychological problem that has been caused or exacerbated by the exercise itself (Adams et al. 2003; Griffiths 1997). Consequently, exercise may be viewed as a continuum. This can range from a healthy and sociable habit, to one that is potentially pathological and addictive (Delatorre 1995). Exercise dependence has been defined as “a craving for leisure-time physical activity that results in uncontrollable excessive exercise behaviour and that manifests itself in physiological and/or psychological symptoms” (Hausenblas and Downs 2002a; p.90). Definitions and measures of exercise dependence have been influenced by a biomedical addiction model (Cox and Orford 2004). To measure and define excessive exercise within this biomedical model, diagnostic criteria for substance dependence outlined in the most recent Diagnostic and statistical manual of mental disorders (DSM-IV; American Psychiatric Association 1994) could be applied to exercise dependence (Adams et al. 2003; Hausenblas and Downs 2002b). This application allows identification of pathological and excessive exercise as an addiction. From an exercise dependence perspective, studies have examined correlates or predictors of exercise dependence. Studies concentrating on exercise dependence have independently examined two different types of determinants—individual factors and characteristics of physical activity. This first group of studies has examined the relationship between individual factors and exercise dependence. Some studies have shown that women display significantly higher levels of exercise dependence than men (e.g., Masters and Lambert 1989; Pierce et al. 1997; Summers et al. 1983), although others have found no such difference (e.g., Furst and Germone 1993). Further studies have reported no association between age and exercise dependence (e.g., Furst and Germone 1993; Klein et al. 2004). In addition to the examination of age and gender, other studies have demonstrated that individuals who exercise excessively risk their social life, marriage and/or close friends (Dishman et al. 1985). A commitment to serious running can be a source of strain in families (Fick et al. 1996). Another relevant variable in relation to exercise dependence is the meaning of the exercise itself to the individual. For instance, a qualitative study by Cox and Orford (2004) showed that the concept of gaining a sense of control through using the body and creating a distinct body shape were two dominant themes. All of these studies appear to show that some individual variables correlate with exercise dependence. However, no study has examined all of these individual factors as an explanation of exercise dependence. A second group of exercise dependence studies has examined the characteristics of physical activity associated with exercise dependence (e.g., frequency, duration, intensity, etc.). Unsurprisingly, exercise dependence has been positively associated with the frequency and duration of exercise (Adams et al. 2003; Furst and Germone 1993). Furthermore, a linear relationship has been reported between participating in competitions of increasing distances and exercise dependence (Pierce et al. 1993.) In one study, ‘ultra marathoners’ showed significantly higher exercise dependence scores when compared to recreational runners or to traditional marathoners (Pierce et al. 1993). The data support habituation effects consistent with acquired dependence behaviour. It has also been demonstrated that intensity is an important correlate of exercise dependence. Using the Leisure Time of Exercise Questionnaire (Godin et al. 1986),

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Hausenblas and Downs (2002b) reported that exercise dependence was associated with strenuous exercise, but not with mild or moderate exercise. These studies showed that frequency of physical activity and intensity were important factors associated with exercise dependence. However, physical activity is also contextual (Marttila et al. 1998). For instance, it has been show that the accessibility and the safety of facilities are associated with physical activity (Humpel et al. 2002). Moreover, exercising with others had an effect on adherence behaviour (Carron et al. 1996). The environmental and social contexts (i.e., where an individual exercises and who they do it with) may be relevant when examining the association between exercise dependence and physical activity. This brief overview shows that there are many studies that have examined the determinants and correlates of exercise dependence. However, there has been a systematic lack of research that has simultaneously examined individual factors, and contextual measures of physical activity characteristics. Furthermore, no study has examined an association of these different levels of determinants in an attempt to explain exercise dependence as defined by diagnostic criteria. Ecological models of physical activity posit that multiple levels of influence determine individual behaviour (Spence and Lee 2003). Such models aim at providing an integrated account of the complex patterns of possible determinants (Humpel et al. 2002). Therefore, the aim of this study is to examine the interaction between both individual variables and characteristics of physical activity in an attempt to explain more fully the concept of exercise dependence. It was hypothesized that there would be a pattern of predictors that explain exercise dependence. This pattern of predictors would be composed of individuals factors (age, gender and BMI) and characteristics of physical activity (total amount of physical activity, and environmental context of physical activity). A second hypothesis was that the characteristics of the physical activity itself would be stronger predictors of exercise dependence than individual factors.

Materials and Methods Participants The sample comprised 95 ‘ultra-marathoners’ who took part in a 100 km race. The total population age ranged from 22- to 79-years (mean age=43.46 years, S.D.=10.98 years). The majority of the participants were male (n=86 men [90.5%] ; n=9 women [9.50%]). The males had a mean age of 43.27 years (S.D.=11.29 years) and the women had a mean age of 43.22 years (S.D.=7.88 years). Measures Socio-demographic Information The questionnaire comprised several items concerning individual factors, items concerning the context of physical activity, and an exercise dependence scale. Individual characteristics items included gender, age, height, weight, marital status (i.e., living alone or living with a partner), and family (with or without children). Participants’ Body Mass Index (BMI) was computed by dividing a participant’s weight (kg) by their height (cm). Physical Activity Participants indicated the different types of physical activity that they engaged in during a typical week. For each physical activity, participants indicated the frequency per week and the mean duration of each session. Participants also indicated

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whether they believed the intensity of each physical activity was “mild,” “moderate,” or “strenuous.” From these data, the overall amount of physical activity was calculated (frequency times duration). In addition, the amount of physical activity was then calculated according to the different intensities (“mild,” “moderate” or “strenuous”). Context of Physical Activity The context of physical activity (i.e., exercise) measured environmental and social characteristics of the participants’ engagement. These contextual variables were based upon those outlined by Cohen-Mansfield et al. (2004) and by Titze et al. (2005). There were seven statements: “You exercise in the city, in a structured space (swimming pool, sport centre, etc,)” “You exercise in the city, in an unstructured space (street, public space and park, etc)” “You exercise in the countryside, in a structured space (railway, health running path, etc)” “You exercise in the countryside, in an unstructured space (forest, on the beach, etc)” “You exercise by yourself” “You exercise together with friends” “You exercise with some family members” Each statement had a 6-point Likert response option, which ranged from ‘1’ (never) to ‘6’ (always). Exercise Dependence Exercise dependence was assessed using the French version of the “Exercise Dependence Scale-Revised” (EDS-R, Downs et al. 2004), which is a 21-item scale using a 6-point Likert Scale from ‘1’ (never) to ‘6’ (always). EDS-R is an assessment of exercise dependence based on the DSM-IV criteria for substance dependence (American Psychiatric Association 1994). Questions on the scale refer to beliefs and behaviours that have occurred within the last three months. EDS-R allows the classification of individuals into three groups: (1) individuals at risk for exercise dependence, (2) non-dependent symptomatic individuals (i.e., individuals may have some exercise dependence symptoms, however these symptoms are not sufficient to classify them as at-risk for exercise dependence), and (3) non-dependent individuals. The total score for the Exercise Dependence Scale-Revised ranged from 21 to 126. Confirmatory factor analyses of original version of EDS-R provided support to present a measurement model (21 items loaded on seven factors) of EDS-R (Comparative Fit Index=0.97; Root Mean Square Error of Approximation (RMSEA)=0.05; Tucker-Lewis Index=0.96). The 7-day test–retest reliability of the EDS-R using the intraclass reliability method was excellent (R=0.95; subscale ranging from 0.75 to 0.95). Factor structure of the French version language of EDS-R was examined with confirmatory factor analysis (CFA). The results of CFA presented the model (with a seven-factor structure) as a good model and fit indices (X2/ddl=2.89, RMSEA= 0.061, Expected Cross Validation Index (ECVI)=1.20, Goodness-of-Fit Index (GFI)=0.92, Comparative Fit Index (CFI)=0.94, Standardized Root Mean Square (SRMS)=0.048). These results showed that the French version of EDS-R has an identical factor structure to the original. Therefore, the French version of EDS-R was an acceptable scale to measure exercise dependence and can be used with a French population.

Procedure All participants were randomly approached during the 2-h race registration procedure. The researcher explained to runners that he was interested in their behaviour and beliefs about

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their physical activities and exercise. They were then asked to complete a questionnaire. If the runners accepted, the participants were informed that the questionnaire was anonymous and were asked to answer the questions spontaneously and as sincerely as they could. Thirty percent of those approached refused to take part in this study because they did not have time. The questionnaire took approximately 20 min to complete. Analysis Data were analyzed with SPSS (Statistical Package for Social Sciences). Two levels of analysis were conducted. Firstly, Pearson correlations examined the association between the total exercise dependence score and other variables. Secondly, variables that were significant in the correlation analysis (where p