fasciculation

https://doi.org/10.1351/goldbook.11769
Involuntary contractions, or twitchings, of groups (fasciculi) of muscle fibers.
Note: This is a coarser form of repetitive muscular contraction than fibrillation.
Source:
PAC, 2015, 87, 841. (IUPAC Glossary of terms used in neurotoxicology (IUPAC Recommendations 2015)) on page 867 [Terms] [Paper]