The relevance of the study of neuromuscular dysfunction's causes and mechanisms is undeniable, considering the large number of nosologies accompanied by malfunction of muscles. Adequate diagnosis and correction of these disorders is impossible without understanding of their pathogenetic mechanisms. Currently, manual muscle testing (MMT) is a widespread technique. MMT is an agile diagnostic tool used by physiatrists, doctors in sports medicine, osteopaths and rehabilitation physicians to assess the functional status of muscles. Unconditionally, this method attracts with its low cost, which will optimize the financial costs of hospital and the healthcare system as a whole. In addition, there is no clear substantiation of the objectivity and validity of the MMT to date. The article considers the issues of neurophysiological principles, classification of methods and approaches, assessment criteria of repeatability and accuracy of MMT. Understanding of the pathophysiological mechanisms of MMT effectiveness will allow to timely correct the therapy and improve the results of treatment and rehabilitation of patients with neuromuscular dysfunction.