Myotonia

Myotonia is a symptom of a small handful of certain neuromuscular disorders characterized by delayed relaxation (prolonged contraction) of the skeletal muscles after voluntary contraction or electrical stimulation. Myotonia is present in myotonia congenita, paramyotonia congenita and myotonic dystrophy. Generally, repeated contraction of the muscle can alleviate the myotonia and relax the muscles thus improving the condition, however, this is not the case in paramyotonia congenita. This phenomenon is known as 'warm-up' and is not to be confused with warming up before exercise, though they may appear similar. Individuals with the disorder may have trouble releasing their grip on objects or may have difficulty rising from a sitting position and a stiff, awkward gait.