<prompt> Condition associated with prolonged muscle contraction followed by slow muscle relaxation includesMyotoniaDystoniaMitochondrial MyopathiesHypotonia  <response>: A 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 may present in the following diseases with different causes related to the ion channels in the skeletal muscle fiber membrane Sarcolemma. Myotonia is present in Myotonia congenita, Paramyotonia Congenita and myotonic dystrophy. 