Characteristics of the fastest isometric knee extension in patients with spinocerebellar degenerations.

The force output of the knee extensor muscles and its time course were measured in nine patients with spinocerebellar degenerations and age-matched 10 normal subjects during the fastest and strongest isometric contraction. The time from the rise of tension to its maximum, FTmax, was definitely long in the SCD compared to the normal group, whereas the peak tension was not different between the two groups. FTmax of the SCD group was not related to the rate of tension development and the maximum tension nor to the degree of ataxia, suggesting that the prolongation of FTmax was a characteristic feature of cerebellar lesions.