The response of the peroneal muscles to sudden inversion of the ankle during standing was investigated. The variation of the inversion angle with time was measured by means of a potentiometer attached to a specially designed test apparatus. During the tests, volunteers were subjected to sudden and unexpected inversion of their ankle, during which the surface EMG of the peroneal muscles was also recorded. Two groups were tested, one of normal subjects and one consisting of subjects with recurrent ankle sprains. There were 8 females and 3 males in each group. The subjects in the second group, who suffered from recurrent ankle sprains, had been asymptomatic during the last 2 months prior to the tests. For each subject in the two groups, both ankles were tested. The results indicated a latency time ranging from 60 to 80 ms for both groups. It was concluded that the reflex contraction of the peroneal muscles due to a sudden stretch inversion motion has no role in protecting the ankle joint during sprain and that this protection is mainly provided by the passive tissues.

Bilateral force measurements on the supporting limbs in postural sway while standing still were made to evaluate post-cerebral-vascular accident (CVA) patients during rehabilitation. Normal subjects of the same age group were tested as controls. From the force tracings obtained, three oscillation frequencies were identified, with orders of magnitudes of 7, 1 and 0.1 Hz, respectively, of which the middle frequency, i.e. that corresponding to 1 Hz, was selected for subsequent processing and analysis. These included the determination of relative sequence of the force vectors on both feet and evaluation of timings and amplitudes of the waveforms. Weight-bearing imbalance was defined in the vertical direction to express the difference between the average forces supported by each of the legs. In the horizontal plane, two parameters were defined: sway total activity (SA), to represent the vector summation of the absolute values of the horizontal force components acting on both legs; and asymmetry (ASYM) to express the difference in activities between the two legs. The results presented disclose the reactive force patterns acting on each of the legs of post-CVA hemiplegic individuals, in comparison with normal individuals. Although these forces were shown to act synchronously on both legs, they appeared to be asymmetrical in nature, with a typical vectorial pattern for every individual, which generally differed from that of normal subjects. Sway activity was found to be significantly higher in hemiplegics compared with the normal controls.

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Background and Purpose: The aim of this study was to determine the predictive yield of upper limb short latency somatosensory evoked potential (USEP) in patients with first stroke in the dominant hemisphere.Methods: Nineteen patients (average age, 58 years) were evaluated twice: on arrival at the rehabilitation center, approximately 3 weeks after the stroke, and again approximately 10 weeks later. The clinical assessment included a quantitative evaluation of motor ability, independence in activities of daily living, and communication ability. USEP was recorded during the week of the initial clinical evaluation. Special attention was paid to the relations between USEP parameters and the dynamics of the clinical condition.Results: The seven patients in whom no cortical potential could be detected showed the worst outcomes; however, the existence of cortical potentials in the remaining 12 patients did not provide a precise prediction of their "rehabilitative capacity" (ie, the extent of their progress). A correlation was established between the amplitude of the potentials recorded over both hemispheres and changes in communication ability. Additional findings included an association between shortened central conduction time over the damaged hemisphere during the first month after stroke and improvement in motor ability.Conclusions: USEP can serve as an adjuvant tool for predicting the recovery progress of stroke patients.