This research study aims to evaluate the effect of a 6-month adapted physical activity program (APA) on the endurance capacities (evaluated as the maximum oxygen consumption [VO2 peak]) of children and adolescents with Osteogenesis Imperfecta.

Osteogenesis Imperfecta (OI) is a rare genetic disease characterised mainly by bone fragility, decreased bone mass and a susceptibility to fractures of varying severity. Different forms have been described according to the severity of the bone manifestations. Although it is a genetically heterogeneous disease, approximately 90% of OI patients have a mutation in the gene encoding gene encoding type 1 collagen, a major component of the extracellular matrix.

Chronic fatigue and decreased physical endurance are almost constant complaints of patients with OI (more than 95% according to some studies), which impacts the activities of daily living and quality of life of these patients. The causes of this decrease in endurance are multifactorial involving prolonged immobilisation secondary to fractures, chronic osteoarticular pain, but also primary muscle damage.

Mechanography studies carried out in children with OI have shown a significant deficit in muscle function in terms of both strength and power.

In healthy adults, physical inactivity is an important predictor of feeling of tired. In addition, in some chronic diseases (such as multiple sclerosis, rheumatoid arthritis or systemic lupus erythematosus), physical activity and training have been shown to be effective in improving muscle strength and functional capacity as well as fatigue and quality of life. In OI, it has been reported that physical activity improves muscle function and bone mass. Patients with OI should therefore benefit from a regular exercise programme taking into account their risk of fracture.

This study aims to evaluate the effect of a life-skills physical activity (LSPA) programme on the endurance capacities and quality of life of children and adolescents with OI.

The VO2 peak evolution will be evaluated after 6 months of program. This is a recognized parameter for the evaluation of endurance and has been validated in children. The hypothesis of this study is that the implementation of a physical activity program adapted to the daily life and interests of the child with OI will efficiently improve endurance, prevent deconditioning and promote long term benefits.

Inclusion Criteria:

• Diagnosed Osteogenesis Imperfecta
• Informed and written consent signed by at least one of the two holders of parental authority
• Patient affiliated to a social security scheme or equivalent

Exclusion Criteria:

• Non-walking children (unable to perform the effort test)
• Pregnant or breastfeeding
• Participation in other interventional research