The subject invention is intended for the use of measuring maximum and explosive muscle strength of lower extremities in various positions whereby depending on the position, the strength of individual muscle groups is measured. The apparatus consists of a basic casing (1), a mechanism for securing fastening which consists of a fixator (2) and belt (3), a mechanism for the angular movement of braces and for fastening (4) upon which braces (5) move and are fastened in a desired position, and a pair of braces with a sensor and lining (6), which are fastened and move in the mechanism for the angular movement of the braces (4), whereby linear movement of the braces (5) and angular rotation of the braces (5) are possible in each mechanism for the angular movement of the braces (4) at any angle, preferably at an angle of 90°.
