Allogeneic haematopoietic stem cell transplantation (aHSCT) is the only curative treatment for many paediatric and young adult haematological pathologies (acute leukaemia, myelodysplastic syndromes haemoglobinopathies, bone narrow aplasia, severe combined immunodeficiency). Despite the major therapeutic progress made over the last 50 years, particularly in terms of supportive care, post-transplant morbidity and mortality remain high. Infectious complications, whose incidence varies between 30 and 60%, are the first cause of mortality in the immediate post-transplant period.

In order to protect the patient from the occurence of severe infectious episodes, aHSCT must be performed in a highly protected environment (positive pressure chambers).

This has consequences for the experience and impact of hospitalization on the patient and family. This is particularly true in pediatrics, with children, adolescents or young adults, where it is not only the patient's quality of life that is at stake, but also his emotional and psychomotor development. In this specific population, prolonged hospitalization (at least 6 weeks) in a sterile room will be responsible for physical deconditioning accompanied by a decrease in muscle mass. Patients often experience an deteriorated quality of life.

Today, the benefits of physical activity (PA) during and after cancer treatment have been widely demonstrated.

The objective of the study is to assess the feasibility of an adapted physical activity program during the isolation phase for achieving aHSCT in children, adolescents and young adults. This is a prospective, interventional, monocentric cohort study conducted at the institute of Paediatric Haematology and Oncology in Lyon. The intervention will take place during the isolation phase and will be based on an adapted physical activity (APA) program defined at inclusion, integrating supervised sessions with an APA teacher, as well as autonomous sessions performed by means of a connected bike in the sterile room. The program will be individualized according to age, aerobic capacities, and PA preferences. Sessions will also be tailored to the biological, psychological, and social parameters of patients.

The total duration of the intervention is 3 months. To date, no PA studies have been performed in patients under 21 years old requiring aHSCT during the sterile isolation phase. EVAADE will therefore be the first study in this population to offer an innovative procedure with a connected device.

Inclusion Criteria:

• 8 years ≤ Age ≤ 21 years
• Height ≥ 110 cm
• Histologically or cytologically confirmed malignant or non-malignant haemopathy
• Indication for hematopoietic stem cell transplantation
• Hospitalization in a sterile room in the investigating center
• Certificate of no contraindicatication to practice an APA, issued by the oncologist or the attending physician
• Having a smartphone available in the sterile room (iOS version 12 (iPhone/Apple) or 6 under Android at least) for playing connected games
• Signed and dated written consent (patient or parents of minor patients with obtaining the minor's acceptance)

Exclusion Criteria:

• Severe heart disease and uncontrolled cardiovascular disease

Temporary contraindications

• Severe anemia (hemoglobin ≤ 8 g/dl) will need to be treated (transfusion of red blood cells [RBCs]) before resuming the physical activity program.
• Severe infectious syndrome in progress and/or febrile feeling with accompanying signs (productive cough, muscle pain).

Inclusion criteria for relatives :

• Person visiting the patient in a sterile room during the hospital stay
• At least 8 years old
• Height ≥ 110 cm
• Have a smartphone (iOS version 12 (iPhone/Apple) or 6 under Android at least) for the realization of the connected games.
• Not having any contraindication to physical activity.
• Signed and dated written consent (minor's relative or parents with the minor's acceptance).