The equipment is used for elbow bending and stretching, and strengthening the muscle chain of the active and antagonistic muscles. On the premise of ensuring the safety of patients, carry out efficient training; The two-way hydraulic resistance can start from the lowest limit set, with small inertia, so as to avoid damage to patients during use; Comfortable use experience. Special design is adopted for the stressed parts of joints, which conforms to the principle of human morphology.