Clonus, spasmgl. : convulsion


Cramps in general are temporary, rhythmically contracting muscle parts (musculature) under pain.


Everybody knows the situation when you feel a twinge, pinch and pull in one muscle during a sporting effort. The musculature has cramped and hurts. As a result, you can no longer call up your performance.

What exactly is hidden behind a cramp, where does it come from and how can I get rid of it or prevent it? A muscle cramp is an involuntary muscle contraction (tension), which occurs, for example, in the calf muscles or the muscles of the thigh, during or after an intensive load. This cramp usually lasts for a few seconds, but is painful and prevents the affected part of the body from functioning normally.

Muscle cramps usually do not originate from the muscle itself, but from the nerve that normally controls the muscle. Via nerve cells, the brain sends signals in the form of electrical impulses to the muscle. These signals decide whether the muscle should relax or tense.

Most cramps occur at the transition from nerve to muscle cell. The nerve cells then send random signals to the muscle cell to contract. The process that the nerves send uncontrolled signals to the muscle, we take as a muscle cramp, in which it comes to a lasting up to minutes of muscle cramp. But not only the muscle cramps, but also the pain receptors in the affected area are excited and thus cause the pain of the cramp. There can be a variety of reasons why this uncontrolled firing of nerve signals occurs.

Causes and forms

It is due to the structure of each muscle that the individual muscle fibers can move interlocked in and against each other and slide past each other. If there is a twisting or interlocking of the individual muscle fibers, this is called a spasm, which makes it impossible for the muscle fibers to glide past each other as usual for a certain period of time, thus guaranteeing normal movement. In most cases, a cramp is accompanied by a hardening of the corresponding muscle area. A general distinction is made between muscle spasms of the striated musculature, which mostly affect palpable muscle parts of the arms and legs, cerebral, neurological spasms and organic spasms of the smooth musculature. The following causes can lead to (nocturnal) cramps of the (calf) musculature:

  • Uncomfortable/unfavorable sleeping position with hyperextended ankle
  • Overloading of the musculature by sports during the day
  • High outside temperature combined with high liquid loss without sufficient compensation
  • Malpositioning of the ankles with increased/unilateral stress on the muscles
  • Signs of aging (in old age one tends to cramps more often).
  • Pregnancy
  • Alcohol consumption
  • Resuming sports after a longer break

The electrolyte balance is responsible for the development of cramps, thus:

  • Deficiency of magnesium, calcium and potassium due to excessive sweating and/or insufficient compensation for fluid loss.
  • Taking medication (especially laxatives, high blood pressure medication, but also contraceptives).
  • Hypomagnesemia (pathological magnesium deficiency)
  • Renal failure
  • Metabolic diseases (hypothyroidism)