title: Control of fast squatting movements after stroke.
abstract: OBJECTIVE
  Little is known about how residual motor impairments after stroke affect the motor control of fast movements, particularly those that combine postural control and limb movement. The purpose of this study was to examine the influence of stroke on the motor control of fast squatting movements.
  
  
  METHODS
  Seventeen individuals with hemiparesis and seventeen age- and sex-matched controls performed fast squatting movements. Force platform data, knee acceleration, and electromyographic activity from rectus femoris, biceps femoris, tibialis anterior, soleus, were collected.
  
  
  RESULTS
  Subjects after stroke performed the squats asymmetrically, with reduced velocity and acceleration compared to controls. Subjects with low motor recovery depended on the non-paretic leg to compensate for poor paretic muscle activation whereas subjects with high motor recovery activated muscles in the paretic leg in an adaptive manner, making the movement more symmetrical. Difficulty with postural control was evident by reduced coupling of the timing of the knee movement with the center of pressure excursion.
  
  
  CONCLUSIONS
  Slow performance of squatting movements was accompanied by altered muscle activation, coupled with impaired postural control.
  
  
  CONCLUSIONS
  Fast squatting movements in standing require appropriate muscle activation and postural control, the latter of which can be measured easily with force platform and accelerometer data.
authors.affiliation: Graduate Program in Health and Rehabilitation Science, The University of Western Ontario, London, ON, Canada.
authors.forename: Vicki L
authors.initials: VL
authors.lastname: Gray
authors.forename: Tanya D
authors.initials: TD
authors.lastname: Ivanova
authors.forename: S Jayne
authors.initials: SJ
authors.lastname: Garland
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography / Q000379:methods; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D010291:Paresis / Q000503:physiopathology* / Q000534:rehabilitation; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D013997:Time Factors