Tele-rehabilitation is emerging as a new opportunity to deliver rehabilitation at patients' home, by extending healthcare services accessibility, ensuring continuity of care and remote monitoring. This is a consequence of COVID-19 pandemic, but it was already becoming particularly relevant for the management of a growing elder population and the higher incidence of chronic diseases. Exercise and specific rehabilitation programs are indeed known to lead to improved motor skills for various clinical conditions. Numerous efforts are being carried out, therefore, on the development of portable devices, suitable for home use, that exploit different technologies, such as cameras or wearable inertial measurement units (IMUs).