Fade in Voluntary Muscle Contractions of Patients with Sequelae after Poliomyelitis

Abstract

The isometric contraction pattern was followed in three female and two male patients with lower motoneuron paralysis due to sequelae from poliomyelitis in 1942-48. In uninstructed contractions, force increased slowly to an almost horizontal level which could be kept up for as long as desired. During rapid maximal voluntary contractions, a "biphasic" mechanogram was seen in 49% of 204 contractions, with a first maximum after 0.3 s (0.1-0.9), separated by a notch from a second maximum after 1.1 s (0.3-2.3). In the rest of the contractions, force could not be generated rapidly, despite the intention of the subjects, and a single maximum in the mechanogram was seen after 0.9 s (0.2-2.4). In contractions where a biphasic contraction pattern was seen, the electromyographic activity was greatest during approximately the first one half second of the contraction. In the other contractions the electromyographic activity was about the same during the whole contraction. The results suggest that the mechanograms are composed of a high innervation threshold, fast phasically active component, and a low innervation threshold, slow tonically active component. Fade represents the waning of tension in the phasically active component present in some contractions, while this component appears to be eliminated by poliomyelitis in other muscle contractions.

Cardiovascular responses at the onset of exercise with partial neuromuscular blockade in cat and man.

“…The large electromyographic activity at the onset of brisk maximal voluntary muscle contractions has been noted previously (Secher, Rube & Molbech, 1981;Larsen, Secher & Rube, 1982, Secher, 1984 and may reflect the electromyographic activity of some fast twitch muscle fibres, as it is enhanced by tubocurarine, and eliminated by decamethonium (Secher et al 1981).…”

Train‐of‐four Fade During Neuromuscular Blockade Induced by Tubocurarine, Succinylcholine or Α‐bungarotoxin in the Rat Isolated Hemidiaphragm

“…The differences in the control responses of the muscles have been attributed to the involvement of different 622.0 7.5k1.2 9.5k1.2 16.8k1.8 28.5k5.6 15.9k2.3 3.3k0.3 8.3k1.1 Succinylcholine 4.3k0.6 3.5k0. 5 2.2k0.2 2.6k0.1 7.6k1.0 6.2k0.8 1.1+.0.1 1.5k0 muscle types with different contraction speed and fatigue characteristics: the soleus consists predominantly of slow twitch fibres whereas the gastrocnemius has predominantly fast twitch fibres; the diaphragm, on the other hand, is a heterogeneous mixture of fast and slow fibres (Riley & Berger 1979;Secher 1984).…”