The SCoRe and SARA operations are provided with Vicon Nexus 2 for research purposes and to enable clinical researchers to assess their use, compared with other methods. You can download the literature for these methods from the Vicon website or obtain it from the group at the University of Berlin. Before using these methods, you are strongly advised to review the published material to understand the methods and best practices for gaining meaningful results.
A review of this literature suggests that for the joints of the lower limbs, SCoRE can produce a meaningful estimation of hip joint center locations. The axes produced by the SARA optimization may not be useful. This is due to ball and socket nature of the joint.
The opposite is suggested for the hinge-link knee joint. The SARA-optimized axis (primary flex/ext axis) may be useful; however the joint center location may not be strictly defined along this axis.
To allow further development and validation of these methods, Nexus does not restrict where they can be run. The operations allow the calculation of SCoRE and SARA for any combination of parent and child segments.
You are responsible for reviewing the published articles before using these operations. Research is continuing the area of functional joint calibration and it is solely your responsibility as the user to determine whether the results from these methods are appropriate for your research outcomes or clinical use.
By combining SCoRE and SARA with an existing Plug-in Gait model, you can obtain full kinematic and kinetic outputs with reduced errors.
To apply SCoRE and SARA to Plug-in Gait, you need to obtain the Plug-in Gait MATLAB script. For more information, contact Vicon Support.
SCoRE is an acronym for Symmetrical Center of Rotation Estimation.
It is an optimization algorithm that uses functional calibration frames between a parent and child segment to estimate the center point of rotation. It is particularly valuable in providing repeatable and -accurate hip joint center locations.
SCoRE locates the joint center only. Kinematics and kinetics must still be calculated by a full biomechanical model (such as Plug-in Gait).
SARA is an acronym for Symmetrical Axis of Rotation Analysis.
It is an optimization algorithm that uses functional calibration frames between a parent and child segment to estimate the axis of rotation. It is particularly valuable in providing repeatable and accurate knee joint axes.
SARA locates the joint axis only. Kinematics and kinetics must still be calculated by a full biomechanical model (such as Plug-in Gait).