title: Comparison between successful and failed sit-to-stand trials of a patient after traumatic brain injury.
abstract: OBJECTIVE
  To compare the peak whole-body center of mass (COM) velocities and joint angular contributions in successful and unsuccessful sit-to-stand (STS) trials in a subject with traumatic brain injury (TBI).
  
  
  METHODS
  Single-case study.
  
  
  METHODS
  Motion research laboratory.
  
  
  METHODS
  A 24-year-old man who was 3.5 years post-TBI.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Peak horizontal and vertical velocities of the whole-body COM and peak angular velocities of the ankle, knee, hip, and shoulder joints.
  
  
  RESULTS
  The peak whole-body COM vertical velocity was significantly lower in the unsuccessful STS trials. Angular velocities at the hip, knee, ankle, and shoulder joints in successful trials exceeded those in unsuccessful trials (P<.001). The subject's peak knee extension velocity was the single major predictor of the peak whole-body COM vertical velocity (r(2)=.90). Knee extension angular velocities greater than 3.25 radian/s were associated with successful STS trials. Knee extension angular velocities between 2.75 and 3.25 radian/s were associated with successful rising 50% of the time; the subject had no success in rising when velocities were less than 2.75 radian/s.
  
  
  CONCLUSIONS
  For this subject, sit-back failures occurred in STS attempts characterized by peak whole-body COM vertical velocities that were lower than those generated in successful rising trials. These unsuccessful rising attempts were primarily the result of the subject's inability to generate sufficient knee extension angular velocity.
authors.affiliation: Department of Physical Therapy, Ithaca College-University of Rochester, NY 14623, USA. czablotny@ithaca.edu
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Zablotny
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Nawoczenski
authors.forename: Bing
authors.initials: B
authors.lastname: Yu
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D001930:Brain Injuries / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D017211:Treatment Failure; D014741:Video Recording