Biomechanic modeling of sit-to-stand to upright posture for mobility assessment of persons with chronic stroke.
OBJECTIVE
To test the suitability of using biomechanic measures associated with a minimum measured input model (MMIM) approach to assess mobility of people with chronic stroke during the execution of a sit-to-stand (STS) to upright posture motor task.


METHODS
Single group, observational.


METHODS
Institutional settings in the United States and Italy.


METHODS
Twenty-nine subjects with chronic unilateral lower-limb impairments and resultant mobility limitations secondary to stroke.


METHODS
Not applicable.


METHODS
Manual measurement of lower-limb strength; performance-based tests including repeated chair standing, walking speed, and standing balance; and ground reactions measured with a force platform during STS and upright posture. The ground reactions were fed to a telescopic inverted pendulum model of the musculoskeletal system. Parameters representing the model outputs were compared with performance-based and strength measures to assess, respectively, motor ability and impairment-related changes in subjects' motor strategies.


RESULTS
The parameters derived from the model effectively differentiated between motor strategies associated with different performance-based scores, and allowed the identification of relevant difficulties encountered in STS execution. These difficulties could be associated with different strength scores. This was also true for subjects scoring the maximum in both performance-based and strength tests.


CONCLUSIONS
The MMIM is a relatively inexpensive and noninvasive approach that enhances mobility assessment of hemiparetic subjects with different motor ability levels. It provides information that correlates well with performance-based and strength scores and, in addition, it allows for subject-specific motor strategy identification.
Mazzà
Claudia
C
Department of Human Movement and Sport Sciences, Istituto Universitario di Scienze Motorie, Rome, Italy. mazza@iusm.it
Stanhope
Steven J
SJ
Taviani
Antonio
A
Cappozzo
Aurelio
A
D000368:Aged; D001696:Biomechanical Phenomena; D002908:Chronic Disease; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D008954:Models, Biological; D009043:Motor Activity / Q000502:physiology; D011187:Posture / Q000502:physiology*; D020521:Stroke / Q000503:physiopathology*; D013647:Task Performance and Analysis