[Purpose] The purposes of this study were to investigate differences between patients
with chronic stroke and age matched healthy controls in trunk stability, by assessing the
kinematics of the center of mass and moving body segments during voluntary limb and trunk
movement, and the relationship between trunk stability and clinical measurements.
[Subjects and Methods] Fifteen stroke patients and 15 age- and gender-matched healthy
subjects participated. Each subject performed flexion of the hip and shoulder of the
non-paretic or matched side as fast as possible, as well as trunk flexion and extension at
a self-selected speed. A Qualisys motion system was employed to track the kinematics of
the trunk and limbs. [Results] Patients presented larger mediolateral displacement of the
center of mass during all limb and trunk movements, and larger velocity of center of mass
during hip flexion movement. Healthy subjects showed greater movement velocity during
shoulder flexion, trunk flexion and extension. Patients’ clinical measurements only
correlated with movement characteristics during voluntary trunk motions. [Conclusion]
Trunk stability in patients with chronic stroke was compromised during voluntary trunk as
well as non-paretic limb movements, and the voluntary trunk movements reflected the trunk
deficits measured using clinical measurements. Rehabilitation of patients with chronic
stroke should include programs to improve trunk stability.