Objective measurements of muscle force in a group of after-stroke patients with hemiparesis

The aim of this study was to estimate the strength of spastic muscles using Biodex System 3 within a group of patients with hemipa-resis in after-stroke population. Measurements of the moments of force in elbow flexors and extensors of both spastic and non-spastic limbs were conducted under isostatic conditions. We analysed the values obtained for both limbs in order to determine the spasticity level on an Ashworth scale (0–4). The subjects were 10 patients with hemiparesis and varying spasticity selected from an after-stroke population. The analysis showed that spastic muscles activated less force than non-spastic muscles of the same patient. Furthermore, in a spastic limb, higher values of force were noted in the flexors than in the extensors of the elbow. In a non-spastic limb, the values of force were higher in the extensors of the elbow joint than in flexors. It is worth adding that the dynamics of force exposure, defined by a gradient of force, was much lower in spastic muscles than in non-spastic ones. Objective estimation of muscle force can be done by measuring the mo-ments of force in particular groups of muscles upon the isokinetic contraction appearing. The repeatability of measurements may enable the kind of kinesitherapy to be determined as well as the assessment of the effectiveness of exercises in regard to force increase and dynamics of spastic muscles. Key words: hemiparesis, spasticity, muscle force, moment of force 1