ABSTRACT
Osteogenesis Imperfecta (OI) is a congenital connective tissue disorder characterized by increased bone fragility and osteopenia. The biochemical basis in most cases involves a quantitative abnormality, qualitative abnormality, or both in the biosynthesis of type I collagen, the principal organic component of the skeleton (Sillence, 1994). Severity varies in a wide range, reaching from intrauterine fractures and perinatal lethality to very mild forms with incidental fractures (Plotkin et al., 2003). Children with mild and moderate forms of OI are in general walkers, varying from household to community walkers (Engelbert et al., 2000). Among these children, fatigue, diminished exercise capacity and exercise intolerance is a frequently reported limitation in their activities of daily living (Engelbert et al., 2004). Takken et al. (2004) studied cardiopulmonary function in 17 children with OI type I. They found that heart and lung abnormalities in rest were absent. However, they also reported that exercise capacity and muscle force were significantly lower when compared to healthy peers. Complaints of fatigue were related to proximal muscle weakness and a reduced peak oxygen uptake (V˙O2peak). It was unclear whether the reduced V˙O2peak and muscle force were a consequence of a hypoactive lifestyle or a specific consequence of the impaired muscle collagen synthesis. Takken et al. (2004) suggested that a physical intervention study in patientswithOImight improve exercise capacity andmuscle force. To our knowledge, no physical intervention studies have been performed in children with OI. Exercise might have no effect on the disease itself, but possibly may improve the performance level of activities of daily living, selfesteem, and fitness inmany of these children.Therefore, we designed a randomized controlled trial to study the effects of a physical training programme on exercise capacity,muscle force, and subjective fatigue in patients with themild tomoderate forms of OI.
