1. O. Verschuren, PT, PhD, Rudolf Magnus Institute of Neuroscience and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, the Netherlands. Mailing address: Rehabilitation Centre De Hoogstraat, Rembrandtkade 10, 3583 TM Utrecht, the Netherlands.
2. M. Zwinkels, MSc, Rudolf Magnus Institute of Neuroscience and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation.
3. M. Ketelaar, PhD, Rudolf Magnus Institute of Neuroscience and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation.
4. F. Reijnders-van Son, PT, MSc, Child Expertise Centre, Tolbrug Specialistic Rehabilitation, 's-Hertogenbosch, the Netherlands.
5. T. Takken, PhD, Child Development and Exercise Center, Wilhelmina Children's Hospital, University Medical Center Utrecht.