Extreme prematurity is constantly increasing according to the World Health Organization. However, methods to train premature infants at risk of disability is sorely lacking. The goal of this project is to overcome this problem. In previous studies, the investigators discovered that promoting the crawling of typical newborns on a mini skateboard, the Crawliskate (a new tool that the investigators designed and patented EP2974624A1), is an excellent way to stimulate infants' motor and locomotor development. This method is a promising way to provide early interventions in infants at heightened risk for developmental delay, such as premature infants. The specific objective of this study is to determine if early training in crawling on this mini skateboard will accelerate motor (particularly locomotor) and/or neuropsychological development in very premature infants identified as high risk for developmental delay. Methodology: The investigators will study and follow two groups of very premature infants born between 24 and 26 weeks of gestational age or born between 26 and 32 with major brain lesions. These infants will be recruited before their hospital discharge at the NICU. After their discharge from the hospital, one group of infants will be trained at home by their parents under the supervision of physiotherapists to crawl on the Crawliskate every day for 2 months (Crawli group), and one group of infants will receive regular medical care (Control group). All infants will be tested for: 1)their crawling proficiency on the Crawliskate at term-equivalent age (just before training for the trained groups) and at 2 and 6 months corrected age (CA, i.e., age determined from the date on which they should have been born), 2) their motor proficiency between 2 and 12 months CA (2D and 3D recording of head control, sitting, crawling, stepping, walking) and 3) their neurodevelopmental, motor and neuropsychological development between 0 and 28 months CA: BSID III edition, ASQ-3, Amiel-Tison's Neurological Assessment, Prechtl Assessment of general movements. One more ASQ-3 questionnaire will be provided at five years. Expected results: The first research hypothesis is that premature infants trained daily to crawl (for two months after discharge from the NICU) will acquire proficient crawling patterns and develop earlier and more effective motor and neuropsychological development than premature infants who receive no training.