A device for assessing and display of a difference in vectors of forces exercised by a pair of arms or legs of exercising persons, e. g. patients suffering from a damage of the musculoskeletal or nervous system or sportsmen comprises a housing (1) with preferably two means (2) for a participation with a pair of limbs-arms or legs, wherein the means (2) are designed in various ways with the purpose to allow proper participation with the treated pair of limbs in an individual exercise, and are arranged on bearings (3) within the housing (1), further comprising a microcontroller (8) and optionally a computer (13), the Internet (14) for connection to an expert centre (15). Each means (2) is connected with a means (4) for the measurement of forces (F). The device of the invention further includes an accelerometer (5), a gyroscope (6) and a magnetometer (7) for the determination of its position and orientation in space, wherein all data from said means (4), said accelerometer (5), said gyroscope (6) and magnetometer (7) are gathered by said microcontroller (8) that evaluates them with models and algorithms, and said data are continuously displayed on a display (9), a monitor or a TV screen, notifying the exercising person on the exercising status and suggesting next steps.