Figure A4.

Mean of intrasubject and intersubject coefficients of determination R² for different linear models between stiffness, force, and EMG and results of performed statistical testing. Mean leave-one-out cross-validated coefficient of determination R² for intrasubject (left; leave-one-trial-out) and intersubject (right; leave-one-subject-out) stiffness and force over all subjects for regressing stiffness from EMG or force, from EMG and force, and for regressing force from EMG using different muscle groups. The SDs over 10 subjects are depicted as error bars.