The Friendly Movements of the Shoulder Joints and Trunk in Healthy Subjects

The trunk, or the torso, is the central part of body in the anatomic relation and plays an important role in pose stabilization, maintenance of balance in daily and household activities and in the maintenance of controlled movements of the upper limbs during task performance. Registration of standard amplitude parameters of conjugate movements of shoulder joints and trunk in the sitting position in healthy subjects can be an important reference point for the recovery of patients with hemiparesis during the acute period of first hemispheric stroke. The study included 25 healthy subjects (11 women, 14 men; medium age: 52.9 ± 11.0 years). We examined the kinematics of conjugate movements in shoulder joints and trunk in the sitting position with the help of inertial sensors recording the movement in three mutually perpendicular planes. We observed specific patterns in the shoulder joints movements and deviations of the trunk in three mutually perpendicular planes. The movement of separate flexing of each arm is characterized by authentically smaller auxiliary movement of the trunk, and the movements of separate abduction and rotation of each hand are characterized by the bigger amplitude of trunk deviation. Trunk involvement becomes a part of the general strategy for achieving the goal of movement in the upper extremity, an important element of balance and a stabilizing component. The method for recording conjugate movements in shoulder joints and trunk in sitting position can be of interest for the medical and scientific institutions which perform motor rehabilitation.