At 1 month postinjection , active range of elbow extension ( goniometry ; primary outcome ) ; active upper limb function ( Modified Frenchay Scale [ MFS ] ) ; subjective global self-assessment ( GSA ) of arm pain , stiffness , and function ; rapid alternating elbow flexion-extension movement frequency over the maximal range ; elbow flexor spasticity grade and angle ( Tardieu ) , and tone ( Ashworth ) .