Impact of a Physical Activity Program to Reduce Long-term Cancer-related Fatigue in Metastatic Testicular Germ Cell Tumor Patients

At the baseline, all participants will receive the international recommendations in terms of physical activity for promoting health in the general population.

At baseline, all participants will receive a connected activity tracker to wear 24 hours a day during one year. Patients will be asked to download an application, dedicated to the study so that the physical activity data (ie. number of steps per day) will be synchronized in the application.

"The intervention will last 1 year and will have 2 phases. Phase 1: At each cycle of chemotherapy, patients will be proposed to perform 2-4 sessions per week. This program will be individual, supervised, performed at a moderate intensity. Between cycles, patients will be asked to perform 1-2 supervised collective live online physical activity sessions per week, proposed by a partner specialized in online PA.~Phase 2: After chemotherapy, patients will be asked to perform 2-3 PA sessions per week at a moderate intensity. Patients will be offered 2 options of PA practice: in the supervised collective live online PA session (as already performed in the phase 1), and/or in a fitness center (this practice will take place in a classic environment with a 9-month free access for patients thanks to a partnership).~In addition, patients will benefit from 4 individual motivational interviews, conducted by videoconference and/or by phone call with a professional."