1. Department of Rehabilitation Medicine, University of Minnesota, MMC 388, 420 Delaware St SE, Minneapolis, MN 55455 (USA). Address all correspondence to Dr Nemanich at: nemanich@umn.edu
2. Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Kowloon, Hong Kong
3. Department of Psychiatry and Behavioral Sciences, University of Minnesota
4. Department of Pediatrics, University of Minnesota
5. Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
6. Department of Pediatrics; and Institute of Child Development, College of Education and Human Development, University of Minnesota
7. Department of Exercise Sciences, University of Auckland, Auckland, New Zealand
8. School of Public Health, Division of Biostatistics, University of Minnesota
9. Department of Rehabilitation Medicine, University of Minnesota