The linear co-variance between joint muscle torques is not a generalized principle

Multi-joint movements with reversal in Parkinson’s disease: Kinematics and electromyography

“…1), each subject was seated upright and performed reversal movements in the sagittal plane, involving elbow and shoulder excursion regarding three target locations, with wrist and hand immobilized by a thermoplastic splint (Sande de Souza et al, 2009). At the initial position, shoulder was at zero degree of flexion (upper arm aligned with the trunk) and elbow at 45°(external angle) measured by the goniometry method before the fixation of the targets.…”

“…From these data, the orientations of the two segments were calculated with respect to X and Y axes in the sagittal plane. Both linear trajectory and velocity of the fingertip were obtained from X and Y coordinates of the distal inter-phalangeal joint (Sande de Souza et al, 2009). Table 1 Information about PD subjects: age (years), sex, height (m), weigh (kg), disease duration (years), motor part of UPDRs (0-56, which means severe), Hoehn and Yahr stages (0-5, which means severe), medication used.…”

“…The straightness index was calculated separately for the two movement phases, i.e., towards and from the target. A constant error was also calculated to determine the amount of absolute undershoot and overshoot in the anterior-posterior (X-axis) and cephalo-caudal directions (Y-axis) (Sande de Souza et al, 2009).…”

Effect of spinal cord injury at C6–C7 on global upper-limb coordination during grasping: Manipulability approach

“…Several indices, such as correlation coefficient [3] or phase plot [4], were used to quantify the degree of coordination, the coupling between shoulder and elbow and the spatiotemporal pattern of joint configurations. To consider more globally the complexity of the upper-limb, multifactorial methods such as * Corresponding author.…”

The manipulability: a new index for quantifying movement capacities of upper extremity

“…For this purpose, several indices were proposed to describe quantitatively the coordination of the DOFS. The simplest ones, the correlation coefficient (Sande de Souza et al 2009) or the phase plots (Cirstea et al 2003) allow to characterise the coupling between two movement parameters such as joint angles, velocities, or torques. The principal component analysis (PCA) allows to study the linear coupling of more than two DOFS during activities such as reaching or grasping (Tseng et al 2003, Hoffmann et al 2006.…”