Switching of movement direction is central to parkinsonian bradykinesia in sit-to-stand

Mov Disord. 2002 Nov;17(6):1188-95. doi: 10.1002/mds.10257.


Patients with Parkinson's disease (PD) are known to manifest slowness in movements. We sought to identify the particular kinematic and kinetic disorders that contribute to the slowness in performing sit-to-stand in these patients. Two inter-related studies were carried out. In the first study, 20 patients with PD and 20 control subjects were instructed to perform sit-to-stand at a natural speed. In the second study, 15 control subjects were instructed to simulate the slower speed of sit-to-stand of the patients identified in the first study. Kinematic and kinetic data were recorded by a PEAK motion analysis system and two force platforms. The results showed that patients with PD generated smaller peak horizontal and vertical velocities during the task. They took a longer time to complete each individual phase as well as the whole movement of sit-to-stand. Patients also produced smaller peak hip flexion and ankle dorsiflexion joint torques and had prolonged time-to-peak torques from sit-to-stand onset. When control subjects simulated the patients' speed of sit-to-stand, there was no difference in all the kinematic and kinetic data between groups. The only exception was that they exhibited a shorter transition time between peak horizontal velocity (flexion phase) and seat-off (extension phase) than the patients. This study demonstrated that the slowness of PD patients during sit-to-stand at a natural speed could be attributed to inadequate peak hip flexion and ankle dorsiflexion torques, a prolonged torque production, as well as a difficulty in switching from the flexion to extension direction during sit-to-stand. As the latter difficulty persisted when the control subjects performed the task at a speed similar to that of the patients, our findings suggest that a fundamental problem of patients with Parkinson's disease could be a switch between movement directions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Biomechanical Phenomena
  • Female
  • Humans
  • Hypokinesia / diagnosis*
  • Hypokinesia / physiopathology
  • Male
  • Middle Aged
  • Neurologic Examination
  • Orientation / physiology*
  • Parkinson Disease / diagnosis*
  • Parkinson Disease / physiopathology
  • Posture / physiology*
  • Reaction Time / physiology*
  • Reference Values
  • Weight-Bearing / physiology