BMC Public Health 2007, 7:230 http://www.biomedcentral.com/1471-2458/7/230 Interpretations The finding that more acculturated migrants were more physically active during their leisure time, is in line with results from other acculturation-studies among several ethnic minority populations, such as the Latino-, and Asian Americans in the US [17,18,20,51,52]. This positive association is often explained by the greater exposure to health promotion campaigns by people who speak the native language and who have many contacts with the host population. As a results their attitudes and norms towards physical activity become more similar to those in the host population. These people might also be better informed about the opportunities for physical activities, for example, how and where they can obtain access to sport facilities. In addition to these studies, the results of the present study indicate that under certain conditions this positive effect of acculturation is not present. We illustrated that barriers such as having children (e.g. time barrier), living in al less attractive environment and participation in occu- pational physical activity modify the association between acculturation and physical activity during leisure time. Although several social cognitive theories that aim to explain behavioural practices, incorporated 'perceived barriers' in their model, this is often indirectly [53,54]. According to these theories, behaviour will only be per- formed when a person perceives no barriers that could inhibit his/her behaviour. However, none of the accultur- ation studies we found paid attention to the role of barri- ers in the association between acculturation and physical activity. This is in line with the conclusion of Hunt et al. (2004) and Salant et al. (2003), who found, in their review-study, that acculturation-studies in general, do not include contextual factors [55,56]. We suggest further study is necessary to unravel more of the potential contex- tual barriers that moderate the effect of acculturation on physical activity. In contrast to most other studies we used a broader meas- ure of acculturation than language use or language profi- ciency alone, instead we included items on shopping preferences, media use, and emancipation as well, in an attempt to cover a more general 'cultural orientation'. The use of 'language proficiency' or 'language use' as indica- tors of acculturation has been criticized by others as it would not necessarily reflect the migrants' adherence to the values and norms within the majority culture [57]. However, the majority of studies on acculturation use these indicators as they seem to be strongly related to sev- eral health related outcomes [58]. Nevertheless, we sug- gest that measuring different domains in which people acculturate might be a better reflection of the process of acculturation, than measuring only language use or lan- guage proficiency. We assume that the pattern of varying influence of accul- turation depending on the presence of contextual barriers, might also apply to other migrant populations. The posi- tive association of acculturation with physical activity (during leisure time) has already been observed among different ethnic minorities and the barriers we included are acknowledged as important constraints for being physically active [17,18,20,33,34,51,52]. We further expect that our results could be generalized to older pop- ulations than those included in our study, as the barriers that we studied are in general more prevalent among adults. The majority of the older migrant adults, belong to the first generation and have on average a greater number of children and a lower socioeconomic position (e.g. more job related physical activity and living in less attrac- tive neighbourhoods) than the young population that we studied [59]. Implications for health promotion Our findings provide indications to suggest that the level of physical activity during leisure time in non-Western migrant populations will not necessarily increase as a con- sequence of greater 'integration' in the host society among people with children, who participate in occupational physical activity or who are living in a less attractive neigh- bourhood. Therefore, we suggest that interventions aimed at specific ethnic groups with high prevalence rates of physical inactivity remain necessary. More specifically, our findings might imply that interventions aimed at pro- moting physical activity among migrants, should not only focus on the least integrated. Instead, effectiveness will probably be enhanced when interventions are sensitive to the social and environmental barriers, especially among low-income migrant populations. Conclusion In conclusion, our study suggest that the influence of cul- tural factors, such as acculturation, might be minimized because of more dominating contextual barriers that inhibit a particular behaviour, which we illustrated with regard to physical activity during leisure time. Therefore, we recommend that in exploring the effect of the process of acculturation on physical activity, it might be necessary to take the social and physical environment into account. Competing interests The author(s) declare that they have no competing inter- ests. Authors' contributions KH carried out the data-collection, performed the data- analysis and drafted the manuscript. NSK was involved in the design of the study and commented on earlier drafts of the manuscript. KS contributed to the conception and design of the study, participated in interpretation of the Page 7 of 9 (page number not for citation purposes)