Functional Implications of Impaired Control of Submaximal Hip Flexion Following Stroke

Introduction: We quantified submaximal torque regulation during low to moderate intensity isometric hip flexion contractions in individuals with stroke and the associations with leg function. Methods: Ten participants with chronic stroke and 10 controls performed isometric hip flexion contractions at 5%, 10%, 15%, 20%, and 40% of maximal voluntary contraction (MVC) in paretic, nonparetic, and control legs. Results: Partici- pants with stroke had larger torque fluctuations (coefficient of variation, CV), for both the paretic and nonparetic legs, than controls (P <0.05) with the largest CV at 5% MVC in the paretic leg (P <0.05). The paretic CV correlated with walking speed (r 2 50.54) and Berg Balance Score (r 2 50.40). At 5% MVC, there were larger torque fluctuations in the contralateral leg dur- ing paretic contractions compared with the control leg. Conclu- sions: Impaired low-force regulation of paretic leg hip flexion can be functionally relevant and related to control versus strength deficits poststroke. Muscle Nerve 49: 225-232, 2014