Muscle slowness in a family with nemaline myopathy.

All patients of a large family with nemaline myopathy complained of slowness in movement. We confirmed this clinical complaint physiologically by showing lower contractile speed in quadriceps muscle. Electrically evoked contractions of the quadriceps muscle elicited a lower rate of relaxation and a tendency for slower torque generation. Here, we demonstrate for the first time slow muscle characteristics as a physiological correlate for the clinical complaint of slowness.