As primary outcome measure will be considered the 6-minute Walking Distance Test. As secondary outcomes measures will be considered Ten Meter Walking Test, Gross Motor Classification System, Child Health Questionnaire (CHQ-PF50) Italian version, Wee FIM and Energy Expenditure Index, Spatio-temporal parameter with GAITRite® System and measure of energy cost by COSMED K4b2. The allocation in the two groups will be done with simple randomisation.