Muscle Cramp

What is a muscle cramp?

A muscle cramp is a sudden and involuntary contraction of one or more of your muscles. Though generally harmless, they can cause severe pain and make it temporarily impossible to use the affected muscle.


What Causes Muscles to Cramp

The cramps that afflict athletes are called “exercise-associated muscle cramps” or EAMCs for short. Muscles don’t cramp on their own. Constant contraction of thousands of muscle fibres are being controlled by nerve signalling.
The gastrocnemius muscle in the calf has 580 motor nerves and each nerve connects to roughly 1,700 muscle fibres. If one motor nerve fires, all 1,700 muscle fibres contract in unison; the more motor nerves that are activated, the stronger the contraction.

Motor nerves are controlled in part by nerves that extend from the brain to the spinal cord. But motor nerves also receive input from thousands of other nerves located in the spinal cord. In fact, two-thirds of the nerves associated with muscles provide this type of sensory feedback to the spine. Each motor nerve receives input from tens of thousands of other nerves.

If one or more motor nerves are constantly stimulated, all the connected muscle fibres contract, when just a few motor nerves become hyper-excited you get muscle twitches and a full-blown cramp when multiple motor nerves are hyper-excited.

Experts now agree that cramps result from an overexcitement of nerves that control muscle contraction, and Heatwave prevents or treats hyper-excitability by restoring the nerve’s normal function.