James R. Gage MD (Medical Director Emeritus, Gillette Children's Specialty Healthcare, St Paul, Minnesota; Professor of Orthopaedics Emeritus, University of Minnesota, Minneapolis, Minnesota, USA) Michael H. Schwartz PhD (Director of Bioengineering Research, Gillette Children’s Specialty Healthcare, St Paul, Minnesota; Associate Professor, Orthopaedic Surgery Graduate Faculty, Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, USA) Steven E. Koop MD (Medical Director, Gillette Children’s Specialty Healthcare, St Paul, Minnesota; Associate Professor of Orthopaedics, University of Minnesota, Minneapolis, Minnesota, USA) Tom F. Novacheck MD (Director, Center for Gait and Motion Analysis, Gillette Children’s Specialty Healthcare, St Paul, Minnesota; Associate Professor of Orthopaedics, University of Minnesota, Minneapolis, Minnesota, USA)