Relationship between static muscle strength deficits and spasticity in stroke patients with hemiparesis.

The purpose of this retrospective investigation was to determine whether a relationship exists between static strength deficits in the shoulder medial (internal) rotator and elbow flexor muscles and spasticity in these muscles or their antagonists. We reviewed the records of the first 50 stroke patients with hemiparesis who met the entry criteria for the study and who were admitted over a four-month period of time. Static muscle strength was measured by hand-held dynamometry. Spasticity was graded on the Ashworth scale. Kendall's tau correlations were calculated between static muscle strength deficits and spasticity. Static strength deficits of the shoulder medial rotator and elbow flexor muscles were correlated (p less than .01) with the agonist muscles' spasticity, but not with the antagonist muscles' spasticity. Muscle group spasticity and strength deficits, therefore, appear to be covarying manifestations of cerebrovascular accidents. Clinicians, thus, may interpret an agonist muscle's capacity for force production in light of its own tone rather than that of its antagonist.