Cramping
Cramping isn't well understood. But here's what we know right now.
The review paper can be read or downloaded HERE.
Muscle Cramping During Exercise: Causes, Solutions, and Questions Remaining. Ronald J. Maughan and Susan M. Shirreffs. Sports Med. 2019; 49(Suppl 2): 115–124. Published online 2019 Nov 6. doi: 10.1007/s40279-019-01162-1 PMCID: PMC6901412, PMID: 31696455