The main objective of this thesis was to analyse the habits, motives and barriers to Leisure Time Physical Activity (LTPA) of adult women in Gipuzkoa. The sub-objectives were: to design an ad hoc questionnaire to analyse the habits, motives and barriers to LTPA of adult women in Gipuzkoa (18-65 years old); to analyse the content validity, ecological validity and internal consistency of the questionnaire; to describe the level of LTPA of adult women, young women, rural adult women and mothers with young children in Gipuzkoa according to the World Health Organization (WHO) physical activity (PA) time recommendations; and to identify and analyse the motives and barriers to LTPA according to feminist approaches and the socio-ecological model. This was a mixed methods study. Quantitative data were collected and analysed first, followed by qualitative data to support or challenge the data previously analysed. In the quantitative part, the ad hoc Gipuzkoan Women's Physical Activity Questionnaire (GWPAQ) was designed and validated. A total of 3595 adult women completed the questionnaire. Pearson's chi-squared test and independent samples test were used to compare the responses between active and inactive groups, with statistical representativeness set at p <, 05. Twenty-five women participated in the qualitative section. Five focus groups were conducted in four different regions of Gipuzkoa. After the verbatim transcription of the interviews, a content analysis was carried out and a categorical system of an inductive-deductive nature was constructed. When analysing the quantitative and qualitative sections, in addition to the group of adult women in Gipuzkoa as a whole, the data of young women (18-29 years old), rural women and rural mothers were also analysed. Indeed, the scientific literature stresses that inactivity tends to increase in these groups of women. Ethical aspects were considered when carrying out this research, which was approved by the Human Research Ethics Committee of the University of the Basque Country (UPV/EHU) (M10-2020-296). The results for content validity, ecological validity and internal consistency of the questionnaire were satisfactory. Among the whole group of respondents, 32% were inactive and 68% active; among the 526 young women, 24% were inactive and 76% active; among the 296 rural women, 37% were inactive and 63% active; and among the 129 rural mothers, 46% were inactive and 54% active. The intrapersonal, interpersonal and contextual motives and barriers varied widely among women in Gipuzkoa. The main motives were related to health, physical appearance and socialisation. The main barriers were lack of time, fatigue, laziness, overwork, the burden

of caregiving tasks and the lack of LTPA services adapted to their needs. In addition to the factors shared by the Gipuzkoan women, for some young women the existence of women's networks and the enjoyment of nature were important motives. In addition, for some young women, negative experiences of physical education and LTPA, feeling uncomfortable in LTPA spaces and experiencing sexist attitudes were major barriers. For some rural mothers, physical and mental fatigue associated with caregiving, lack of shared caregiving responsibilities between partners, guilt associated with care ethics, and health problems associated with pregnancy, postpartum and age were important factors. They also highlighted specific aspects related to the rural environment, such as the lack of adapted roads, the rugged terrain and the lack of services adapted to their needs. Therefore, the motives and barriers of women in this research showed that women have specific needs and that the patriarchal structure and gender roles and stereotypes of LTPA influence their habits, motives and barriers. It is important to meet women's needs and recognise their diversity in order to access and enjoy the benefits of LTPA. To do this, it is important to consider intrapersonal, interpersonal and contextual factors and to have a feminist approach, which is essential to identify gender discrimination. Finally, it is important to see women not as passive subjects but as agents of change, capable of empowering themselves and transforming gender power relations.