Muscle spasms are involuntary contractions of a muscle. These are muscle spasms.
Athletes sometimes get cramps in their muscles during strenuous activity.
These cramps are also spasms. A common name for a muscle cramp or spasm is charley horse. This term is especially used for cramps in the leg. A spasm usually occurs from overusing muscles or from an injury. If you are dehydrated during strenuous activity, you are likely to have cramps.