Division of Physical Therapy, Department of Orthopedics, Duke University School of Medicine, Durham, NC 27710, USA.Division of Physical Therapy, Department of Orthopedics, Duke University School of Medicine, Durham, NC 27710, USA.Division of Physical Therapy, Department of Orthopedics, Duke University School of Medicine, Durham, NC 27710, USA.Division of Physical Therapy, Department of Orthopedics, Duke University School of Medicine, Durham, NC 27710, USA.Division of Physical Therapy, Department of Orthopedics, Duke University School of Medicine, Durham, NC 27710, USA.Division of Physical Therapy, Department of Orthopedics, Duke University School of Medicine, Durham, NC 27710, USA.