Conclusions : Age-related differences support the impact of stroke-related sarcopenia as a contributor to hemiparetic muscle dysfunction .
Abstract Background : Despite extensive study of the impact of stroke on muscle and functional performance , questions remain regarding the extent to which changes are due to the neurological injury vs. age-related loss of morphology and force production .
Objectives : To synthesize available evidence describing post-stroke changes in lower extremity muscle size and strength compared to healthy adults .
Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip flexors.
OBJECTIVE To determine , using the Muscular Utilization Ratio ( MUR ) method , whether plantarflexor weakness is among the factors preventing stroke subjects from walking at faster speeds . Potential compensations by the hip flexors were also examined . DESIGN A convenience sample of 17 chronic stroke subjects in a context of a descriptive study . BACKGROUND Gait speed is correlated with the residual strength of the muscles involved in gait in stroke subjects . However , it has not been established if this residual strength limits gait speed . METHODS  Kinetic and kinematic data for comfortable and maximal gait speeds were collected on the paretic side , and were used to determine the  moments in plantarflexion ( mechanical dem and : MUR numerator ) during the push-off phase . The maximal potential moment ( MUR denominator ) of the plantarflexors during gait was predicted using an equation derived from dynamometric data collected with a Biodex system . The MURs of the plantarflexors  were then calculated at every 1 % interval of the push-off phase . The pull-off phase of gait and the hip flexor strength were also examined . RESULTS Ten subjects of the sample had a MUR value between 80 and 150 % at maximal gait speed . These subjects produced the lowest peak torques in plantarflexion . Each of the four fastest subjects of this group had a large hip flexion moment during the pull-off phase of gait and produced high hip flexion torque values on the dynamometer . Each of the seven remaining subjects had a MUR value under 70 % when they walked at maximal speed . CONCLUSIONS Weakness of the plantarflexors should be considered as one factor limiting gait speed in 10 hemiparetic subjects . Some subjects with weak plantarflexors could walk rapidly because they compensated with the hip flexors . For the remaining stroke subjects , factors other than weakness of the plantarflexors have to be considered in order to explain the reduction in their gait speed
Conclusions : Age-related differences support the impact of stroke-related sarcopenia as a contributor to hemiparetic muscle dysfunction .
Abstract Background : Despite extensive study of the impact of stroke on muscle and functional performance , questions remain regarding the extent to which changes are due to the neurological injury vs. age-related loss of morphology and force production .
Objectives : To synthesize available evidence describing post-stroke changes in lower extremity muscle size and strength compared to healthy adults .