Predicate: flexion
Roleset id: flexion.01 , Tensing a muscle by contraction, vncls: , framnet:
flexion.01: flex.01
Roles:
        Arg0: Agent, flexor
        Arg1: Flexing part, muscle
Example: Arg1
        person: ns,  tense: ns,  aspect: ns,  voice: ns,  form: ns
        Patient is experiencing tenderness at the joint line upon flexion of the knee.
        Rel: flexion
        Arg1: of the knee