Motor unit organization of human medial gastrocnemius.
Article first published online: 1 FEB 1979
© 1979 The Physiological Society
The Journal of Physiology
Volume 287, Issue 1, pages 33–43, February 1, 1979
How to Cite
1979), Motor unit organization of human medial gastrocnemius.. The Journal of Physiology, 287 doi: 10.1113/jphysiol.1979.sp012643., , , , (
- Issue published online: 1 FEB 1979
- Article first published online: 1 FEB 1979
- Cited By
1. The properties of fifty-seven motor units in human medial gastrocnemius have been studied using controlled intramuscular microstimulation, glycogen depletion and muscle biopsy. 2. Motor units could be divided into three classes on the basis of their mechanical properties. Type S units were slow, small and fatigue resistant. Type FR units were fast, intermediate in size, and fatigue resistant. Type FF units were fast, large and fatigable. 3. Glycogen depletion of a number of type S and FF units revealed them to be composed of type 1 and type 2b muscle fibres respectively. 4. The results suggest that during slowly increasing voluntary contractions where units are recruited in order of size, type 1 and 2a muscle fibres would be employed at low force levels followed by type 2b muscle fibres in stronger contractions.