About 5% of breast cancers are metastatic at diagnosis and 20-30% of localized breast cancer become secondarily metastatic.Thanks to recent therapeutic advances, the median survival ranges between 12 months in 1970 and 18 to 24 months in 2000. However, patients suffer from many detrimental symptoms such as fatigue, pain related to treatment and metastasis. The physical, biological, psychological and clinical benefits of physical activity (PA) during treatment in patients with localized breast cancer have been widely demonstrated. Numerous studies investigated the effect of PA in non-metastatic breast cancer, but to our knowledge, only four interventional studies worldwide focused on the implementation of PA in patients with metastatic breast cancer.It seems appropriate to investigate the feasibility of PA intervention with patients with metastatic breast cancer to see if the observed effects in localized breast cancer are confirmed in metastatic breast cancer population. The ABLE study is an interventional cohort designed to assess the feasibility of a 6-month adapted physical activity intervention, performed under real life conditions in patients with metastatic breast cancer.