The study of movement has always fascinated artists, photographers and researchers. Across the years, several attempts to capture, freeze, study and reproduce motion were made. Nowadays, the possibility to have quantitative data may support the diagnosis and treatment of many pathologies. Thus, in many rehabilitation facilities, a motion analysis laboratory is considered a must-have for diagnosis and patient's monitoring. This paper reviews the first historical attempts, based on photography, and their earliest results, till the state-of-the-art technology used today, i.e. the optoelectronic system.Working principle of the optoelectronic system is described as well as its application and setup in the clinical practice. Modern functional evaluation protocols are reviewed, with pro and cons and examples of clinical results and discoveries. Results of measurements conducted on subjects with neuro-motor pathologies are reviewed. Special attention is paid to the most common motion analysis exam that is nowadays worldwide standardized, i.e. the Gait Analysis. Examples of Gait Analysis on subjects with pathology and follow-up are reviewed.