Affiliations: [a] Department of Rehabilitation Medicine, Skåne
University Hospital, Lund, Sweden | [b] Department of Health Sciences, Lund University, Lund,
Sweden
Note: [] Address for correspondence: Ulla-Britt Flansbjer, PhD,
Department of Rehabilitation Medicine, Skåne University Hospital, 221 85
Lund, Sweden. Tel.: +46 413 55 66 35; Fax: +46 413 55 67 09; E-mail:
ulla-britt.flansbjer@med.lu.se
Abstract: The aim of this study was to assess knee extensor and flexor muscle
torque in individuals with hemiparesis after stroke and determine the
relationship with muscle tone. Fifty individuals (mean age 58 ± 6.4
years), 6 to 48 months after stroke, participated in the study. Maximal
concentric knee extension and flexion torque at 60°/s and 120°/s and
maximal eccentric knee extension contractions at 60°/s were measured with a
Biodex dynamometer. Muscle tone was assessed with the modified Ashworth Scale.
The relative weakness in the paretic knee muscles ranged from 30% to 42% and
was greater for the flexors and at higher velocities (p< 0.05). The knee
flexion/extension torque ratio in the non-paretic lower limb was 0.53 for both
velocities and significantly lower (p< 0.01) for the paretic lower limb
(0.44 at 60°/s and 0.39 at 120°/s). The eccentric/concentric ratio in
the paretic lower limb (1.66) was significantly higher (p< 0.05) than in the
non-paretic lower limb (1.31). Concentric torque in the paretic lower limb was
significantly correlated (p< 0.05) with muscle tone. In conclusion,
post-stroke weakness of the knee muscles was most prominent in the flexors and
at higher velocities, whereas eccentric strength seemed to be preserved.
Strength was also associated with the spasticity that can occur after stroke.
This post-stroke muscle weakness pattern could be of importance for gait
performance and should therefore be accommodated when planning rehabilitation
interventions.
